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Intellectual disability - microarray and sequencing v5.520 DENND5B Sarah Leigh gene: DENND5B was added
gene: DENND5B was added to Intellectual disability - microarray and sequencing. Sources: Literature
Mode of inheritance for gene: DENND5B was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: DENND5B were set to 38387458
Phenotypes for gene: DENND5B were set to DENND5B associated neurodevelopmental disorder
Review for gene: DENND5B was set to GREEN
Added comment: DENND5B variants have not previously been associated with a phenotype in OMIM, Gen2Phen or MONDO. PMID: 38387458 reports five de novo missense variants in five unrelated cases. The carriers of these DENND5B variants have a neurodevelopmental disorder, which is characterized by psychomotor delay (5/5 cases), intellectual disability, ranging from severe to mild (3/5 cases, although one of the negative cases was a 2 year old child, who was considered to be too young to make the assessment, although the DD/intellectual disability phenotype was considered to be moderate in this case), epilepsy (2/5 cases) and hypotonia (4/5 cases). The authors of PMID: 38387458 also report the functional effects of the DENND5B variants, which revealed defective intracellular vesicle trafficking, with significant impairment of lipid uptake and distribution. They conclude that this effect is likely to be caused by the predicted disruption of protein folding in the variant DENND5B peptide.
Sources: Literature
Intellectual disability - microarray and sequencing v5.487 ZFX Sarah Leigh changed review comment from: A single ZFX variant has been associated with a neurodevelopmental disorder, that has a Rett syndrome-like phenotype disorder, in a 14 year old male. The ZFX variant was allelic with another X-linked variant in SHROOM4. These variants were inherited from the mother, who had random X inactivation pattern (PMID: 26740508).
PMID: 38325380 reports 11 ZFX variants in 18 subjects from 16 unrelated families (14 males and 4 females) with an X-linked neurodevelopmental disorder with recurrent facial gestalt. Seven variants were truncating and the remaining were missense variants within the Zinc finger array. In the pedigree of family 6 (figure 3, PMID: 38325380), it was apparent that there were female carriers of the ZFX variant (GRCh38 chrX: 24229396A>G, c.2438A>G, p.Tyr774Cys) with hyperparathyroidism and two affected males and one affected female, with the neurodevelopmental disorder. It appeared that skewed X-inactivation in the female carriers was responsible for the different phenotypic features. The association between ZFX variants and a novel neurodevelopmental disorder, was further supported by functional studies showing altered transcriptional activity in missense variants and altered behavior in a zebrafish loss-of-function model.; to: To date, germline variants in ZFX have not been associated with a phenotype in OMIM or Gen2Phen.
A single ZFX variant has been associated with a neurodevelopmental disorder, that has a Rett syndrome-like phenotype disorder, in a 14 year old male. The ZFX variant was allelic with another X-linked variant in SHROOM4. These variants were inherited from the mother, who had random X inactivation pattern (PMID: 26740508).
PMID: 38325380 reports 11 ZFX variants in 18 subjects from 16 unrelated families (14 males and 4 females) with an X-linked neurodevelopmental disorder with recurrent facial gestalt. Seven variants were truncating and the remaining were missense variants within the Zinc finger array. In the pedigree of family 6 (figure 3, PMID: 38325380), it was apparent that there were female carriers of the ZFX variant (GRCh38 chrX: 24229396A>G, c.2438A>G, p.Tyr774Cys) with hyperparathyroidism and two affected males and one affected female, with the neurodevelopmental disorder. It appeared that skewed X-inactivation in the female carriers was responsible for the different phenotypic features. The association between ZFX variants and a novel neurodevelopmental disorder, was further supported by functional studies showing altered transcriptional activity in missense variants and altered behavior in a zebrafish loss-of-function model.
Intellectual disability - microarray and sequencing v5.400 ACBD6 Sarah Leigh edited their review of gene: ACBD6: Added comment: ACBD6 variants have not been associated with a phenotype in OMIM, and as an autosomal recessive condition with Limited strength in Gen2Phen. Three variants have been reported in three unrelated cases with intellectual disability, however, in one of these carriers the ACBD6 variant was allelic with PRDX6 gene c.136del; p.(ValCysfs*23), therefore the contribution of the ACBD6 variant to intellectual disability is uncertain in this case (PMID: 21937992, 32108178).; Changed rating: AMBER
Intellectual disability - microarray and sequencing v5.369 TRPC5 Sarah Leigh changed review comment from: To date, TRPC5 variants have not been associated with a phenotype in OMIM, however, Gen2Phen lists TRPC5 as having an Limited association with the phenotype of TRPC5-related neurodevelopmental disorder. Six TRPC5 have been reported to be associated with a neurodevelopmental disorder, which has a range of phenotypic features, including intellectual disability and autism spectrum disorder (PMIDs: 36323681;33504798;28191890;23033978).; to: To date, TRPC5 variants have not been associated with a phenotype in OMIM, however, Gen2Phen lists TRPC5 as having an Limited association with the phenotype of TRPC5-related neurodevelopmental disorder. Six TRPC5 variants have been reported to be associated with a neurodevelopmental disorder, which has a range of phenotypic features, including intellectual disability and autism spectrum disorder (PMIDs: 36323681;33504798;28191890;23033978).
Intellectual disability - microarray and sequencing v5.368 TRPC5 Sarah Leigh commented on gene: TRPC5: To date, TRPC5 variants have not been associated with a phenotype in OMIM, however, Gen2Phen lists TRPC5 as having an Limited association with the phenotype of TRPC5-related neurodevelopmental disorder. Six TRPC5 have been reported to be associated with a neurodevelopmental disorder, which has a range of phenotypic features, including intellectual disability and autism spectrum disorder (PMIDs: 36323681;33504798;28191890;23033978).
Intellectual disability - microarray and sequencing v5.354 CDK16 Sarah Leigh edited their review of gene: CDK16: Added comment: To date, CDK16 variants have not been associated with a phenotype in OMIM, but have a limited association with intellectual disability (ID) in Gen2Phen. Four CDK16 variants have been associated with a spectrum of phenotypic features, including ID (n= 3), autism spectrum disorder (n= 3), seizures (n= 2) and spacity (n= 2)(PMID:36323681, 31981491, 25644381).; Changed rating: GREEN
Intellectual disability - microarray and sequencing v5.338 ZBTB47 Sarah Leigh edited their review of gene: ZBTB47: Added comment: ZBTB47 variants have not been associated with a phenotype in OMIM, Gen2Phen or MONDO. PMID: 37743782 reports five unrelated patients with de novo missense variants in ZBTB47 (c.2039A>G, p.(Glu680Gly) in one patient and c.1429G>A, p.(Glu477Lys) in four others), with a phenotype that included developmental delay, intellectual disability, seizures, hypotonia, gait abnormalities, and variable movement abnormalities.; Changed rating: GREEN
Intellectual disability - microarray and sequencing v5.328 MAST4 Sarah Leigh edited their review of gene: MAST4: Added comment: MAST4 variants have not been associated with a phenotype in OMIM, Gen2Phen or MONDO to date. PMID: 36910266 reports three de novo heterozygous MAST4 missense variants in four unrelated cases, with a neurodevelopmental disorder, including cognitive delay/intellectual disability and PMID: 33057194 reports four heterozygous MAST4 missense variants in four unrelated cases and a terminating variant in an additional case, from a cohort of 31,058 parent-offspring trios of individuals with developmental disorders. Between these two publications there are five missense MAST4 variants and one terminating variant. Variant c.4412C>T (p.Thr1471Ile) was seen in three unrelated cases.; Changed rating: GREEN
Intellectual disability - microarray and sequencing v5.325 RBL2 Sarah Leigh edited their review of gene: RBL2: Added comment: RBL2 variants have been associated with Brunet-Wagner neurodevelopmental syndrome (OMIM:619690) but not with phenotype in Gen2Phen. To date six RBL2 variants have been reported in four unrelated cases of OMIM:619690 (PMIDs: 32105419; 33980986).; Changed rating: GREEN; Changed mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability - microarray and sequencing v5.255 PABPC1 Sarah Leigh edited their review of gene: PABPC1: Added comment: PABPC1 variants have not been associated with a phenotype in OMIM, Gen2Phen or MONDO. PMID: 35511136 reports four de novo PABPC1 variants in four unrelated cases with a phenotype of global DD, movement coordination disorders,
seizures, behavioral disorders and mild facial dysmorphisms. Intellectual disability ranged in the cases from profound (1/4), IQ: 61 (1/4) and IQ: 79 (2/4). Seizures were apparent in the all of the three cases where it was assessed.
Molecular modeling of the variants suggested that they would result in a reduced binding affinity to the messenger RNA metabolism-related protein - PAIP2. This predicted effect was seen in coimmunoprecipitation assays between variant PABPC1 and PAIP2 (PMID: 35511136). Further functional studies in PMID: 35511136, showed that the proliferation of neural progenitor cells in Pabpc1 knockdown mouse embryo brains were decreased, this effect was rescued by the wild-type Pabpc1, but not by the variants c.1691A>G (p.Glu564Gly) or c.1709T>C (p.Ile570Thr).
Other variants were identified in 3/4 cases in PMID: 35511136, two of these had a ACMG VUS classification (RBBP4: c.845A>G, p.(Asn282Ser), IGF2R: c.1850G>A p.Cys617Tyr), while the third variant was monoallelic, whereas bialleic variants in this gene are associated with disease (KDM5B: c.2265dupA, p.(Tyr755*))(PMID: 35511136, table 1).; Changed rating: GREEN
Intellectual disability - microarray and sequencing v5.234 LETM1 Sarah Leigh changed review comment from: LETM1 variants has been associated with Neurodegeneration, childhood-onset, with multisystem involvement due to mitochondrial dysfunction, OMIM:620089 and as moderate Gen2Phen gene for LETM1-related neurodevelopmental disorder.
PMID: 36055214 reports 10 LETM1 variants in 18 patients from 11 unrelated families with childhood-onset neurodegeneration with multisystem involvement, many of whom were gathered using the GeneMatcher Program. The most common clinical features of this cohort, where an assessment could be made, were: mitochondrial respiratory complex deficiencies 11/11 (100%), global developmental delay / intellectual disability 17/18 (94%), bilateral sensorineural hearing loss 11/14 (78%) , impaired vision 10/10 (100%), cerebellar ataxia 7/9 (78%), seizures 10/15 (67%), hypotonia 11/18 (61%) (PMID: 36055214, figure 1c).; to: LETM1 variants have been associated with Neurodegeneration, childhood-onset, with multisystem involvement due to mitochondrial dysfunction, OMIM:620089 and as moderate Gen2Phen gene for LETM1-related neurodevelopmental disorder.
PMID: 36055214 reports 10 LETM1 variants in 18 patients from 11 unrelated families with childhood-onset neurodegeneration with multisystem involvement, many of whom were gathered using the GeneMatcher Program. The most common clinical features of this cohort, where an assessment could be made, were: mitochondrial respiratory complex deficiencies 11/11 (100%), global developmental delay / intellectual disability 17/18 (94%), bilateral sensorineural hearing loss 11/14 (78%) , impaired vision 10/10 (100%), cerebellar ataxia 7/9 (78%), seizures 10/15 (67%), hypotonia 11/18 (61%) (PMID: 36055214, figure 1c).
Intellectual disability - microarray and sequencing v5.233 SLC22A5 Sarah Leigh changed review comment from: Comment on mode of inheritance: The mode of inheritance for SLC22A5 variants should be BOTH Monoallelic and Biallelic. Although, most of the evidence for symptoms associated SLC22A5 are seen in a patients with biallelic variants (HGNC:10969, OMIM:603377, Gen2Phen, Orphanet:118781, ClinGen), a few individuals heterozygous for SLC22A5 variants have been seen with a milder phenotype (PMID: 10545605; 11261427).; to: Comment on mode of inheritance: The mode of inheritance for SLC22A5 variants should be BIALLELIC, autosomal or pseudoautosomal. Although, heterozygous SLC22A5 variants have been seen in a few cases, these are detectable biochemically and are not associated with clear clinical presentation (PMID: 10545605; 11261427).
Intellectual disability - microarray and sequencing v5.227 SLC22A5 Sarah Leigh Added comment: Comment on mode of inheritance: The mode of inheritance for SLC22A5 variants should be BOTH Monoallelic and Biallelic. Although, most of the evidence for symptoms associated SLC22A5 are seen in a patients with biallelic variants (HGNC:10969, OMIM:603377, Gen2Phen, Orphanet:118781, ClinGen), a few individuals heterozygous for SLC22A5 variants have been seen with a milder phenotype (PMID: 10545605; 11261427).
Intellectual disability - microarray and sequencing v5.190 EIF4A2 Sarah Leigh gene: EIF4A2 was added
gene: EIF4A2 was added to Intellectual disability - microarray and sequencing. Sources: Literature
Q3_23_promote_green tags were added to gene: EIF4A2.
Mode of inheritance for gene: EIF4A2 was set to BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Publications for gene: EIF4A2 were set to 36528028
Phenotypes for gene: EIF4A2 were set to Neurodevelopmental disorder
Review for gene: EIF4A2 was set to GREEN
Added comment: EIF4A2 has not been associated with a phenotype in OMIM, Gen2Phen or Mondo at the time of reporting. PMID: 36528028 reports the findings of an international collaboration through Matchmaker Exchange, where EIF4A2 variants are found in cases with neurodevelopmental disorder characterized by intellectual disability, hypotonia, and epilepsy. A total of 15 EIF4A2 variants have been reported in PMID: 36528028, with 12 variants occurring as de novo monoallelic in 12 individuals and 3 as biallelic in two unrelated cases (one as homozygote and the other as compound heterozygous). Severe intellectual was seen in 6/10 unrelated cases where an assessment was made, epilepsy was evident in 10/14 unrelated cases and 13/14 cases had hyptonia. Functional studies were also presented and it would appear that both loss and gain functions maybe associated with EIF4A2 variants.
Sources: Literature
Intellectual disability - microarray and sequencing v5.188 TTI1 Sarah Leigh gene: TTI1 was added
gene: TTI1 was added to Intellectual disability - microarray and sequencing. Sources: Literature
Mode of inheritance for gene: TTI1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TTI1 were set to 36724785
Phenotypes for gene: TTI1 were set to neurodevelopmental disorder with microcephaly
Review for gene: TTI1 was set to GREEN
Added comment: TTI1 has not previously been associated with a phenotype in OMIM, Gen2Phen or MONDO. At least 2 variants have been reported. PMID: 36724785 reported 15 TTI1 variants as either homozygotes (2 families) or compound heterozygotes (7 families) in cases with a neurodevelopmental disorder with microcephaly. In all cases the parents were heterozygous carriers of the TTI1 variant identified in the affected child. Development delay was observed in all of the families (9/9), moderate to severe intellectual disability was evident in all families where it could be assessed (8/8) and severe microcephaly was present in members of 5/9 families. Supportive functional results were also presented.
Sources: Literature
Intellectual disability - microarray and sequencing v5.160 POU3F2 Sarah Leigh gene: POU3F2 was added
gene: POU3F2 was added to Intellectual disability - microarray and sequencing. Sources: Literature
Q2_23_promote_green tags were added to gene: POU3F2.
Mode of inheritance for gene: POU3F2 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: POU3F2 were set to 37207645
Phenotypes for gene: POU3F2 were set to neurodevelopmental delay with hyperphagic obesity
Review for gene: POU3F2 was set to GREEN
Added comment: Not associated with a phenotype in OMIM, Gen2Phen or MONDO. PMID: 37207645 reports eight POU3F2 variants in the unrelated cases of neurodevelopmental delay with hyperphagic obesity, with no other variants detected in other candidate genes. Intellectual disability was apparent in 6/7 of these cases from infancy to early childhood. The remaining variant : NM_005604.4 c.135C>A, p.Tyr45* was found in a mother and son, where the son was classified as having intellectual disability, the mother did not. Excluding the mother and son, all of the remaining cases carrying POU3F2 variants had neurodevelopmental delay.
Sources: Literature
Intellectual disability - microarray and sequencing v5.108 LHX2 Sarah Leigh gene: LHX2 was added
gene: LHX2 was added to Intellectual disability - microarray and sequencing. Sources: Literature
Q2_23_promote_green tags were added to gene: LHX2.
Mode of inheritance for gene: LHX2 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: LHX2 were set to 37057675
Phenotypes for gene: LHX2 were set to neurodevelopmental disorder
Review for gene: LHX2 was set to GREEN
Added comment: Not associated with a phenotype in OMIM, Gen2Phen or MONDO. PMID: 37057675 reports 17 predominanly de novo LHX2 variants in a panel of patients with a variable neurodevelopmental disorder. Haploinsufficiency and functional studies are supportive of a loss-of-function pathogenic action of the reported LHX2 variants.
Sources: Literature
Intellectual disability - microarray and sequencing v5.12 MED11 Sarah Leigh gene: MED11 was added
gene: MED11 was added to Intellectual disability - microarray and sequencing. Sources: Literature
Q2_23_promote_green tags were added to gene: MED11.
Mode of inheritance for gene: MED11 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: MED11 were set to 36001086
Phenotypes for gene: MED11 were set to MED11-associated neurodevelopmental disorder
Review for gene: MED11 was set to GREEN
Added comment: Not associated with a phenotype in OMIM, but is associated with MED11-associated neurodevelopmental disorder in Gen2Phen. PMID: 36001086 reports a single MED11 variant (NM_001001683.4: c.325C>T, p.Arg109*), that segregates with the condition in five unrelated families, however, there is homozygosity between two of these families, idicating that they may be related. Global delay was observed in three individuals from three unrelated familes and seizures were evident in four individuals from four unrelated families. Severe microcephaly was apparent in the two unrelated familes where this parameter was recorded. Overall, the MED11-associated neurodevelopmental disorder appeared to result in profound effects and proved fatal at birth and 10 days in two of the cases reported.
Sources: Literature
Intellectual disability - microarray and sequencing v4.51 ZMYM3 Sarah Leigh edited their review of gene: ZMYM3: Added comment: Not associated with a phenotype in OMIM, Gen2Phen or MONDO. Using the MatchMaker Exchange, PMID: 36586412 reports 23 ZMYM3 variants in 27 individuals (24 males, 3 females) with a neurodevelopmental delay phenotype. Of those assessed 17/20 had intellectual disability, there were other features that overlapped between the individuals including speech delay, motor delay, ASD traits, behavioral problems, facial dys-morphism, microcephaly, short stature.; Changed rating: GREEN; Changed publications to: 36586412; Changed phenotypes to: neurodevelopmental delay
Intellectual disability - microarray and sequencing v4.43 TMEM147 Sarah Leigh gene: TMEM147 was added
gene: TMEM147 was added to Intellectual disability. Sources: Literature
Q1_23_promote_green tags were added to gene: TMEM147.
Mode of inheritance for gene: TMEM147 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TMEM147 were set to 36044892
Phenotypes for gene: TMEM147 were set to Neurodevelopmental disorder with facial dysmorphism, absent language, and pseudo-Pelger-Huet anomaly, OMIM:620075
Review for gene: TMEM147 was set to GREEN
Added comment: Associated with relevant phenotype in OMIM and as strong Gen2Phen gene. PMID: 36044892 reports 12 variants in at least 15 unrelated derived from GeneMatcher. Supportive functional evidence is also presented.
Sources: Literature
Intellectual disability - microarray and sequencing v4.42 PAN2 Sarah Leigh edited their review of gene: PAN2: Added comment: PAN2 is not associated with a phenotype in OMIM, but has a moderate association with PAN2-related neurodevelopmental disorder with multiple congenital anomalies in Gen2Phen. PMID: 29620724 reports one homozygous variant in one case and PMID: 35304602 reports a further three homozygous variants in three unrelated cases. It would appear that the syndrome associated with PAN2 variants has multiple congenital anomalies (PMID: 35304602, table 1), including intellectual disabilty ranging from mild to global developmental delay.; Changed rating: GREEN
Intellectual disability - microarray and sequencing v4.38 HIST1H4F Sarah Leigh edited their review of gene: HIST1H4F: Added comment: H4C6 is not associated with a phenotype in OMIM or Gen2Phen. PMID: 35202563 reports single H4C6 variant in a case with a neurodevelopmental syndrome, based on functional studies, the authors suggest that the variant does not have a loss of function action.; Changed rating: RED
Intellectual disability - microarray and sequencing v4.38 HIST1H4I Sarah Leigh commented on gene: HIST1H4I: Associated with Tessadori-van Haaften neurodevelopmental syndrome 4, (OMIM:619951), but not with a phenotype in Gen2Phen. PMID: 35202563 reports two H4C9 variants in two patients with a neurodevelopmental syndrome, based on functional studies, the authors suggest that the variants do not have a loss of function action.
Intellectual disability - microarray and sequencing v4.36 HIST1H4E Sarah Leigh edited their review of gene: HIST1H4E: Added comment: Associated with in Tessadori-van Haaften neurodevelopmental syndrome 3 (OMIM:619950), but not with a phenotype in Gen2Phen. PMID: 35202563 reports seven H4C5 variants in 17 patients with a neurodevelopmental syndrome, based on functional studies, the authors suggest that the variants do not have a loss of function action.; Changed rating: GREEN
Intellectual disability - microarray and sequencing v4.34 ZNF292 Sarah Leigh edited their review of gene: ZNF292: Added comment: Associated with relevant phenotype in OMIM and as strong Gen2Phen gene. At least seven autosomal dominant or de novo ZNF292 variants have been reported in at least eleven unrelated cases of Intellectual developmental disorder, autosomal dominant 64 (OMIM: 619188)(PMID: 31723249).; Changed rating: GREEN
Intellectual disability - microarray and sequencing v4.13 BUB1 Sarah Leigh edited their review of gene: BUB1: Added comment: Not associated with a phenotype in OMIM, but has a moderate association with BUB1-related microcephaly and developmental disorder in Gen2Phen. PMID: 35044816 reports three BUB1 variants in two cases of developmental delay, including microcephaly, together with supportive functional studies.; Changed rating: GREEN
Intellectual disability - microarray and sequencing v3.1736 DPH5 Sarah Leigh edited their review of gene: DPH5: Added comment: Not associated with a phenotype in OMIM, but as moderate Gen2Phen gene for DPH5-related neurodevelopmental disorder. PMID: 35482014 reports four DPH5 variants in fives cases from three unrelated families. Biallelic NM_001077394.2:c.521dup (p.Asn174LysfsTer10) was identified in a consanguinous family (PMID: 35482014, family 3), the index case, an affected sibling and cousin all died in infancy. Affected members families 1 & 2 (PMID: 35482014) were seen in childhood, all had profound intellectual disability and seizures were seen in both families. A supportive mouse model was described, as were in vitro functonal studies (PMID: 35482014).; Changed rating: GREEN
Intellectual disability - microarray and sequencing v3.1736 DPH5 Sarah Leigh Added comment: Comment on phenotypes: As described by Gen2Phen (https://www.ebi.ac.uk/gene2phenotype/gfd?dbID=4902).
Intellectual disability - microarray and sequencing v3.1731 DOHH Sarah Leigh gene: DOHH was added
gene: DOHH was added to Intellectual disability. Sources: Literature
Mode of inheritance for gene: DOHH was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: DOHH were set to 35858628
Phenotypes for gene: DOHH were set to DOHH associated neurodevelopmental disorder
Review for gene: DOHH was set to GREEN
Added comment: Not associated with a phenotype in OMIM, Gen2Phen or MONDO. PMID: 35858628 reports six DOHH variants in three unrelated cases of a neurodevelopmental disorder. All of these cases had intellectual disability, microcephaly and hypotonia.
Sources: Literature
Intellectual disability - microarray and sequencing v3.1726 SCAMP5 Sarah Leigh changed review comment from: Comment on list classification: Not associated with phenotype in OMIM (last edited on 10/06/2014) or in Gen2Phen. Two variants have been identified in three unrelated cases (one monoallelic, one biallelic). Supportive functional studies have been reported.
It would appear that the two variants reported so far in this gene result in differing mode of pathogenicity and phenotypic features. With heterozygous c.538G>T, p.Gly180Trp seeming to have a dominant-negative effect resulting in autistic spectrum disorder, intellectual disability and seizures. While homozygous c.271C>T, p.R91W seems to have a loss of function effect resulting in early onset epilepsy and Parkinson’s disease. This may be due to different functional domains of the mature protein being altered.
Based on this evidence, SCAMP5 is rated as Amber, with a Watchlist tag. This status may change if further cases are reported.; to: Comment on list classification: Not associated with phenotype in OMIM (last edited on 10/06/2014) or in Gen2Phen. Two variants have been identified in three unrelated cases (one monoallelic, one biallelic). Supportive functional studies have been reported.
It would appear that the two variants reported so far in this gene result in differing mode of pathogenicity and phenotypic features. With heterozygous c.538G>T, p.Gly180Trp seeming to have a dominant-negative effect resulting in autistic spectrum disorder, intellectual disability and seizures. While homozygous c.271C>T, p.R91W seems to have a loss of function effect resulting in early onset epilepsy and Parkinson’s disease. This may be due to different functional domains of the mature protein being altered.
Based on this evidence, SCAMP5 is rated as Amber, with a Watchlist tag. This status may change if further cases are reported.
Intellectual disability - microarray and sequencing v3.1714 ANK3 Sarah Leigh edited their review of gene: ANK3: Added comment: Associated with Intellectual developmental disorder, autosomal recessive 37 (OMIM:615493) in OMIM, but not associated with a phenotype in Gen2Phen. At least six ANK3 variants have now been associated with an autosomal dominant neurodevelopmental condition (PMIDs: 23390136; 28687526; 34218362). These terminating variants affect the transcripts for all of the ANK3 isoforms and are de novo (where trio evidence is available).; Changed rating: GREEN; Changed mode of inheritance: BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Intellectual disability - microarray and sequencing v3.1707 STUB1 Sarah Leigh Added comment: Comment on mode of inheritance: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. Numerous STUB1 variants have been reported in both Autosomal recessive spinocerebellar ataxia type 16, OMIM:615768 and Spinocerebellar ataxia 48, OMIM:618093. PMIDs 34906452; 35493319 report digenic occurrence of heterozygous STUB1 variants, with TBP_CAG expansions of 41-46. They question the validy of Spinocerebellar ataxia 48 (OMIM:618093) as a condition and whether it should be included into Spinocerebellar ataxia 17 (OMIM:607136).
Intellectual disability - microarray and sequencing v3.1701 CPSF3 Sarah Leigh changed review comment from: Associated with relevant phenotype in OMIM and as moderate Gen2Phen gene for CPSF3-associated neurodevelopmental disorder with seizures and microcephaly. PMID: 35121750 reports two CPSF3 variants in cases, c.1403G>A, p.Gly468Glu (NM_016207.3) in two Icelandic families and c.1061T>C, p.Ile354Thr (NM_016207.3) in a large consanguineous Mexican family. Intellectual disabililty was evident in all 8/8 cases and seizures and microcephaly was apparent 7/8 cases (PMID: 35121750).; to: Associated with relevant phenotype in OMIM and as moderate Gen2Phen gene for CPSF3-associated neurodevelopmental disorder with seizures and microcephaly. PMID: 35121750 reports two CPSF3 variants in cases, c.1403G>A, p.Gly468Glu (NM_016207.3) in two Icelandic families and c.1061T>C, p.Ile354Thr (NM_016207.3) in a large consanguineous Mexican family. Intellectual disabililty was evident in all 8/8 cases and seizures and microcephaly was apparent 7/8 cases (PMID: 35121750).
The rating of this gene could be changed to green, if further disease associated variants are identified or supportive functional studies are reported.
Intellectual disability - microarray and sequencing v3.1695 FBXO28 Sarah Leigh edited their review of gene: FBXO28: Added comment: Associated with relevant phenotype in OMIM and as definitive Gen2Phen gene. At least six variants have been reported in at least six cases. In one of these cases the variant was inherited from the unanaffected mother, who was mosaic (PMID: 33280099), otherwise the variants were de novo heterozygotes (PMIDs: 30160831; 33280099).; Changed rating: GREEN
Intellectual disability - microarray and sequencing v3.1694 CDK9 Sarah Leigh edited their review of gene: CDK9: Added comment: Not associated with a phenotype in OMIM, Gen2Phen or MONDO. At least four variants have been reported in unrelated cases with a CHARGE-like syndrome:
NM_001261:c.280C>T, p.Arg94Cys (PMID: 29302074)
NM_001261.3:c.673C>T / p.Arg225Cys (PMID: 26633546, 30237576)
NM_001261.3:c.862G>A / p.Ala288Thr and c.907C>T /p.Arg303Cys (PMID: 33640901).
Supportive functional studies have also been reported (PMID: 33640901).; Changed rating: GREEN
Intellectual disability - microarray and sequencing v3.1693 CCDC32 Sarah Leigh edited their review of gene: CCDC32: Added comment: Associated with relevant phenotype in OMIM and as strong Gen2Phen gene for CCDC32-associated neurodevelopmental syndrome. At least three variants have been reported in three unrelated cases (PMIDS: 32307552 & 35451546), together with supportive functional studies.; Changed rating: GREEN
Intellectual disability - microarray and sequencing v3.1689 GLRA2 Sarah Leigh edited their review of gene: GLRA2: Added comment: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. PMID: 35294868 reports eight GLRA2 variants in affected females (n=8) and males (n=5). The variants in the females were de novo and c.887C>T,
p.Thr296Met (NC_000023.10, chrX: g.14627284C>T) was present in six individuals (PMID: 35294868, table 2) and was found to have a gain-of-function effect, which is in contrast to c.754C>T, p.Arg252Cys and c.407A>G, p.Asn136Ser (PMID: 2637014). All of the 13 GLRA2 variant carriers in PMID: 35294868 had developmental delay/intellectual disability and epilepsy was evident in 7/13 of the cases (PMID: 35294868, table 2). Supportive functional studies were also presented.; Changed rating: GREEN
Intellectual disability - microarray and sequencing v3.1687 NRCAM Sarah Leigh edited their review of gene: NRCAM: Added comment: Associated with relevant phenotype in OMIM and as moderate Gen2Phen gene for NRCAM neurodevelopmental disorder with dysmorphic features, hypotonia and spasticity. At least 12 variants have been reported in PMID: 35108495 in 8 unrelated cases (table 1). Global developmental delay / intellectual disabilty was evident in 5/7 unrelated cases (individual 1 was not considered as they also had homozygous loss-of-function variant in CD55 (OMIM: 125240)(PMID: 35108495).; Changed rating: GREEN
Intellectual disability - microarray and sequencing v3.1684 TIAM1 Sarah Leigh edited their review of gene: TIAM1: Added comment: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. PMID: 35240055 reports six TIAM1 variants in four unrelated cases (5 cases in total) of Neurodevelopmental disorder with language delay and seizures, OMIM:619908. All of the cases displayed seizures and intellectual disability, where an assessment was made. The drospohila ortholog (still life) and funtional studies supported this gene disease association (PMID: 35240055).; Changed rating: GREEN
Intellectual disability - microarray and sequencing v3.1682 CPSF3 Sarah Leigh changed review comment from: Associated with relevant phenotype in OMIM and as moderate Gen2Phen gene for CPSF3-associated neurodevelopmental disorder with seizures and microcephaly. PMID: 35121750 reports two CPSF3 variants in cases, c.1403G>A, (NM_016207.3) in two Icelandic families and c.1061T>C (NM_016207.3) in a large consanguineous Mexican family.; to: Associated with relevant phenotype in OMIM and as moderate Gen2Phen gene for CPSF3-associated neurodevelopmental disorder with seizures and microcephaly. PMID: 35121750 reports two CPSF3 variants in cases, c.1403G>A, p.Gly468Glu (NM_016207.3) in two Icelandic families and c.1061T>C, p.Ile354Thr (NM_016207.3) in a large consanguineous Mexican family. Intellectual disabililty was evident in all 8/8 cases and seizures and microcephaly was apparent 7/8 cases (PMID: 35121750).
Intellectual disability - microarray and sequencing v3.1680 PDZD8 Sarah Leigh changed review comment from: Not associated with a phenotype in OMIM, Gen2Phen or MONDO. PMID: 35227461 reports two PDZD8 variants in two unrelated cases with a neurodevelopmental cognitive disorder. The PDZD8 variants were biallelic in the affected cases in two unrelated families, but heterozygous or absent in the unaffected family members (figure 1 PMID: 35227461). Supportive animal models were also presented in PMID: 35227461.; to: Not associated with a phenotype in OMIM (last edited: 02/21/2018), Gen2Phen or MONDO. PMID: 35227461 reports two PDZD8 variants in two unrelated cases with a neurodevelopmental cognitive disorder. The PDZD8 variants were biallelic in the affected cases in two unrelated families, but heterozygous or absent in the unaffected family members (figure 1 PMID: 35227461). Supportive animal models were also presented in PMID: 35227461.
Intellectual disability - microarray and sequencing v3.1680 PDZD8 Sarah Leigh edited their review of gene: PDZD8: Added comment: Not associated with a phenotype in OMIM, Gen2Phen or MONDO. PMID: 35227461 reports two PDZD8 variants in two unrelated cases with a neurodevelopmental cognitive disorder. The PDZD8 variants were biallelic in the affected cases in two unrelated families, but heterozygous or absent in the unaffected family members (figure 1 PMID: 35227461). Supportive animal models were also presented in PMID: 35227461.; Changed rating: GREEN
Intellectual disability - microarray and sequencing v3.1679 CHKA Sarah Leigh edited their review of gene: CHKA: Added comment: Not associated with a phenotype in OMIM, Gen2Phen or MONDO. PMID: 35202461 reports five CHKA variants in five unrelated cases with a neurodevelopmental disorder, which includes intellectual disability, epileptic
encephalopathy and severe microcephaly (PMID: 35202461). Suportive functional studies are also presented in this article.; Changed rating: GREEN
Intellectual disability - microarray and sequencing v3.1628 SEMA3E Sarah Leigh gene: SEMA3E was added
gene: SEMA3E was added to Intellectual disability. Sources: Literature
Mode of inheritance for gene: SEMA3E was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: SEMA3E were set to 35628442
Phenotypes for gene: SEMA3E were set to Severe Intellectual Disability with Cognitive Regression
Review for gene: SEMA3E was set to AMBER
Added comment: Not associated with a phenotype in OMIM or Gen2Phen. One variant has been reported in a case of Severe Intellectual Disability with Cognitive Regression (PMID: 35628442). PMID: 35628442 also describes functional studies which show that this variant impairs protein secretion and hampers the binding to both embryonic mouse neuronal cells and tissues, furthermore, SEMA3E was revealed to be expressed during human brain development.
Sources: Literature
Intellectual disability - microarray and sequencing v3.1614 ATP6V0A1 Sarah Leigh Added comment: Comment on phenotypes: Phenotype from Gen2Phen https://www.ebi.ac.uk/gene2phenotype/gfd?dbID=4422
Intellectual disability - microarray and sequencing v3.1612 ATP6V0A1 Sarah Leigh edited their review of gene: ATP6V0A1: Added comment: Not associated with a phenotype in OMIM, but as definitive Gen2Phen gene for ATP6V0A1-related developmental disorder (monoallelic). At least four variants have been reported as de novo heterozygous variants in 14 apparently unrelated cases, with intellectual disability (11/11 cases who could be assessed), epilepsy/EEG abnormalities (11/13 who could be assessed), microcephaly (6/12 cases who could be assessed), ataxia (6/13 cases who could be assessed) and various other phenotypic features (PMID: 34909687 (table 1) & 33833240). Six additional ATP6V0A1 variants were reported as biallelic in four apparently unrelated cases, who all had intellectual disability, epilepsy/EEG abnormalities plus cerebral and cerebellar atrophy / brain atrophy (PMID: 34909687 (table 1) & 33833240).; Changed rating: GREEN; Changed mode of inheritance: BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Intellectual disability - microarray and sequencing v3.1612 ATP6V0A1 Sarah Leigh changed review comment from: Comment on mode of inheritance: Monallelic mode of inheritance has been selected for ATP6V0A1, although four families showed biallelic ATP6V0A1 variants. This in line Gen2Phen and the views Zornitza Stark and Mike Spiller who have reviewed this gene, and reflects the inconstitancies of the phenotypes amongst these individuals. As more data is obtained, it maybe that the mode of inheritance is changed to both mono and biallelic.; to: Comment on mode of inheritance: Monoallelic mode of inheritance has been selected for ATP6V0A1, although four families showed biallelic ATP6V0A1 variants. This in line Gen2Phen and the views Zornitza Stark and Mike Spiller who have reviewed this gene.
Intellectual disability - microarray and sequencing v3.1611 ATP6V0A1 Sarah Leigh changed review comment from: Comment on mode of inheritance: Monallelic mode of inheritance has been selected for ATP6V0A1, although four families showed biallelic ATP6V0A1 variants. This in line the views Zornitza Stark and Mike Spiller who have reviewed this gene, and reflects the inconstitancies of the phenotypes amongst these individuals. As more data is obtained, it maybe that the mode of inheritance is changed to both mono and biallelic.; to: Comment on mode of inheritance: Monallelic mode of inheritance has been selected for ATP6V0A1, although four families showed biallelic ATP6V0A1 variants. This in line Gen2Phen and the views Zornitza Stark and Mike Spiller who have reviewed this gene, and reflects the inconstitancies of the phenotypes amongst these individuals. As more data is obtained, it maybe that the mode of inheritance is changed to both mono and biallelic.
Intellectual disability - microarray and sequencing v3.1607 TMEM63C Sarah Leigh gene: TMEM63C was added
gene: TMEM63C was added to Intellectual disability. Sources: Literature
Q3_22_rating tags were added to gene: TMEM63C.
Mode of inheritance for gene: TMEM63C was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TMEM63C were set to 35718349
Phenotypes for gene: TMEM63C were set to hereditary spastic paraplegia, MONDO:0019064
Review for gene: TMEM63C was set to GREEN
Added comment: Not associated with a phenotype in OMIM, Gen2Phen or MONDO. PMID:35718349 reports four TMEM63C variants in seven individuals from three unrelated families with childhood onset hereditary spastic paraplegia, with mild intellectual disability in some cases. Functional studies in PMID:35718349, reveal a role for TMEM63C in regulating both endoplasmic reticulum and mitochondrial morphologies.
Sources: Literature
Intellectual disability - microarray and sequencing v3.1604 SYNE2 Sarah Leigh gene: SYNE2 was added
gene: SYNE2 was added to Intellectual disability. Sources: Literature
Mode of inheritance for gene: SYNE2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: SYNE2 were set to 34573277
Phenotypes for gene: SYNE2 were set to autism spectrum disorder, developmental delay and intellectual disability
Review for gene: SYNE2 was set to RED
Added comment: Biallelic SYNE2 variants are not associated with autism spectrum disorder, developmental delay and intellectual disability in OMIM or Gen2Phen. PMID: 34573277 reports compound heterozygous SYNE2 variants in a child with autism spectrum disorder, developmental delay and intellectual disability, together with supportive functional studies.
Sources: Literature
Intellectual disability - microarray and sequencing v3.1600 ZMYM2 Sarah Leigh edited their review of gene: ZMYM2: Added comment: Associated with relevant phenotype in OMIM and as strong Gen2Phen gene for ZMYM2-related developmental disorder (monoallelic). At least 3 variants have been reported in cases with mild to unclassified intellectual disability in PMID: 32891193. The review from Tracy Lester (Genetics laboratory, Oxford UK) mentions several additional de novo variants reported by Decipher associated with intellectual / developmental disability.; Changed rating: GREEN
Intellectual disability - microarray and sequencing v3.1599 CUL3 Sarah Leigh edited their review of gene: CUL3: Added comment: Associated with relevant phenotype in OMIM and as definitive Gen2Phen gene. At least seven variants have been reported in publications (PMIDs: 32341456;25969726;31696658;33097317;30311385) in at least seven unrelated cases, together with a case reported by Julie Evans (South West Genomic Laboratory Hub) all being diagnosed with Neurodevelopmental disorder with or without autism or seizures, OMIM:619239. Severe intellectual disability (ID) was observed in two of these cases, mild in three cases and unclassified ID in another case. Seizures were also evident in three cases and a febrile seizure was reported in another case.; Changed rating: GREEN
Intellectual disability - microarray and sequencing v3.1590 SRRM2 Sarah Leigh edited their review of gene: SRRM2: Added comment: Not associated with a phenotype in OMIM and as definitive Gen2Phen gene for SRRM2-related developmental disorder (monoallelic). At least 22 loss of function SRRM2 variants have been reported in PMID: 35567594 in unrelated cases of which 16/20 exhibit variable mild intellectual disability.; Changed rating: GREEN
Intellectual disability - microarray and sequencing v3.1589 SRRM2 Sarah Leigh changed review comment from: Comment on phenotypes: SRRM2-related developmental disorder (monoallelic) is the phenotype listed by Gen2Phen (https://www.ebi.ac.uk/gene2phenotype/gfd?dbID=4427) to be associated with SRRM2 variants.; to: Comment on phenotypes: SRRM2-related developmental disorder (monoallelic) is the phenotype listed by Gen2Phen (https://www.ebi.ac.uk/gene2phenotype/gfd?dbID=4427) to have a definitive association with SRRM2 variants.
Intellectual disability - microarray and sequencing v3.1589 SRRM2 Sarah Leigh Added comment: Comment on phenotypes: SRRM2-related developmental disorder (monoallelic) is the phenotype listed by Gen2Phen (https://www.ebi.ac.uk/gene2phenotype/gfd?dbID=4427) to be associated with SRRM2 variants.
Intellectual disability - microarray and sequencing v3.1587 PRPF8 Sarah Leigh edited their review of gene: PRPF8: Added comment: Associated with Retinitis pigmentosa 13 (OMIM:600059) in OMIM, but not with PRPF8-related developmental disorder (monoallelic) and as a both RD and IF Gen2Phen gene for PRPF8-related developmental disorder (monoallelic). PMID: 35543142 reports 14 PRPF8 variants in unrelated cases (12/14 variants were confirmed as de novo). Intellectual disability was observed in 13/14 of these cases and seizures were evident in 4/14 cases.; Changed rating: GREEN
Intellectual disability - microarray and sequencing v3.1587 PRPF8 Sarah Leigh Added comment: Comment on phenotypes: Gen2Phen phenotype: PRPF8-related developmental disorder (monoallelic) in addition to Retinitis pigmentosa 13
Intellectual disability - microarray and sequencing v3.1580 SOX11 Sarah Leigh Added comment: Comment on phenotypes: Described as MENTAL RETARDATION, AUTOSOMAL DOMINANT, 27 by Gen2Phen (https://www.ebi.ac.uk/gene2phenotype/gfd?dbID=405).
Intellectual disability - microarray and sequencing v3.1576 THUMPD1 Sarah Leigh changed review comment from: Not associated with a phenotype in OMIM or MONDO, but as moderate Gen2Phen gene for THUMPD1 neurodevelopment disorder. At least 7 variants have been reported, together with supportive functional studies (PMID: 35196516).; to: Not associated with a phenotype in OMIM or MONDO, but as moderate Gen2Phen gene for THUMPD1 neurodevelopment disorder. At least 8 variants have been reported in at least 7 unrelated cases, together with supportive functional studies (PMID: 35196516).
Intellectual disability - microarray and sequencing v3.1576 THUMPD1 Sarah Leigh edited their review of gene: THUMPD1: Added comment: Not associated with a phenotype in OMIM or MONDO, but as moderate Gen2Phen gene for THUMPD1 neurodevelopment disorder. At least 7 variants have been reported, together with supportive functional studies (PMID: 35196516).; Changed rating: GREEN
Intellectual disability - microarray and sequencing v3.1576 THUMPD1 Sarah Leigh Added comment: Comment on phenotypes: Phenotype name based on Gen2Phen entry (https://www.ebi.ac.uk/gene2phenotype/gfd?dbID=4827).
Intellectual disability - microarray and sequencing v3.1573 ZBTB7A Sarah Leigh edited their review of gene: ZBTB7A: Added comment: Associated with relevant phenotype in OMIM and as limited Gen2Phen gene. At least 11 variants have been reported in 10 unrelated cases.; Changed rating: GREEN
Intellectual disability - microarray and sequencing v3.1465 ATP9A Sarah Leigh edited their review of gene: ATP9A: Added comment: Not associated with a phenotype in OMIM, Gen2Phen or MONDO. At least four variants reported in four unrelated families with a neurodevelopmental disorder (PMIDs: 34379057, 34764295). Model Atp9a−/− mice had neurobehavioural disabilities reminiscent to the behavioral patterns in the publications quoted here (PMID: 27626380).; Changed rating: GREEN; Changed publications to: 27626380
Intellectual disability - microarray and sequencing v3.1352 SNIP1 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as possible Gen2Phen gene. A single (founder) variant NM_024700.4:c.1097A>G, p.(Glu366Gly) has been reported in over 30 cases of Psychomotor retardation, epilepsy, and craniofacial dysmorphism OMIM:614501 in the Amish community (PMIDs: 22279524; 34570759). Cases are homozygous for this variant and unaffected members of the families are heterozygous or wt. Overexpression of the equivalent mouse variant in mouse inner medullary collecting duct cells, resulted in a more aggregated appearance in the nucleus compared to wildtype. The variant protein maybe unstable as Western blots showed reduced levels of the variant protein (PMID: 22279524). Whole transcriptomic analysis of patient blood was performed in PMID: 34570759. This revealed 11 upregulated and 32 downregulated genes, of which 24 had previously been associated with neurological disease.
Intellectual disability - microarray and sequencing v3.1272 GNB1 Sarah Leigh Added comment: Comment on mode of pathogenicity: Gen2Phen entry for GNB1 (https://www.ebi.ac.uk/gene2phenotype/gfd?dbID=2121) lists the mutation consequence summary as Activating
Intellectual disability - microarray and sequencing v3.1200 CEP85L Sarah Leigh edited their review of gene: CEP85L: Added comment: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least nine variants reported in nine unrelated families. PMID 32097630 comments that - the CEP85L gene as a whole is tolerant to loss of function and to missense variation. However, the 4 missense variants that have been identified in patients affect a 15-aa region of the protein that is highly intolerant to missense variation, the splicing and start-loss variants are predicted to produce a shortened protein that excludes the same 15-aa region. It is speculated that variants in this constrained region, may act through a dominant-negative mechanism.
Intellectual disability was apparent in eight of the families studied, ranging from mild (three families) to moderate (five families).
Supportive studies were also presented (PMID 32097630, 32097629).; Changed rating: GREEN
Intellectual disability - microarray and sequencing v3.1195 PCDHGC4 Sarah Leigh changed review comment from: Not associated with a phenotype in OMIM, Gen2Phen or MONDO. At least eight variants reported in 19 members of nine unreleted families with a neurodevelopmental syndrome. Severe or moderate intellectual disabilty was found in eight families and seizures were evident in four families. Four of the variants were terminating, in silico analysis of the remaining missense (n=3) and splice variants were predicted to be pathogenic.
Sources: Literature; to: Not associated with a phenotype in OMIM, Gen2Phen or MONDO (15/7/2021). At least eight variants reported in 19 members of nine unreleted families with a neurodevelopmental syndrome. Severe or moderate intellectual disabilty was found in eight families and seizures were evident in four families. Four of the variants were terminating, in silico analysis of the remaining missense (n=3) and splice variants were predicted to be pathogenic.
Sources: Literature
Intellectual disability - microarray and sequencing v3.1194 PCDHGC4 Sarah Leigh gene: PCDHGC4 was added
gene: PCDHGC4 was added to Intellectual disability. Sources: Literature
Q3_21_rating tags were added to gene: PCDHGC4.
Mode of inheritance for gene: PCDHGC4 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: PCDHGC4 were set to 34244665
Phenotypes for gene: PCDHGC4 were set to neurodevelopmental syndrome
Review for gene: PCDHGC4 was set to GREEN
Added comment: Not associated with a phenotype in OMIM, Gen2Phen or MONDO. At least eight variants reported in 19 members of nine unreleted families with a neurodevelopmental syndrome. Severe or moderate intellectual disabilty was found in eight families and seizures were evident in four families. Four of the variants were terminating, in silico analysis of the remaining missense (n=3) and splice variants were predicted to be pathogenic.
Sources: Literature
Intellectual disability - microarray and sequencing v3.1180 SPTBN1 Sarah Leigh gene: SPTBN1 was added
gene: SPTBN1 was added to Intellectual disability. Sources: Literature
Q3_21_rating tags were added to gene: SPTBN1.
Mode of inheritance for gene: SPTBN1 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: SPTBN1 were set to 34211179
Phenotypes for gene: SPTBN1 were set to autosomal dominant neurodevelopmental syndrome
Review for gene: SPTBN1 was set to GREEN
Added comment: Not associated with a phenotype in OMIM, Gen2Phen or MONDO (as of 13/07/2021). At least 27 monoallelic variants reported in 29 individuals with neurodevelopmental abnormalities. Developmental delay was reported in 28/28 tested cases. Intellectual disabilty was reported in 21/24 tested cases (including severe in 5 cases, moderate to severe in 2 cases and moderate in 4 cases) and epilepsy/seizures was reported in 9/24 tested cases (including febrile seizures in 2 cases). Extensive supportive functional evidence was also reported (PMID 34211179).
Sources: Literature
Intellectual disability - microarray and sequencing v3.1179 NAA20 Sarah Leigh changed review comment from: Not associated with a phenotype in OMIM nor Gen2Phen. Two missense variants reported as homozygotes in one family each. In silico predictions and in vitro functional studies provide evidence that these variants will adversely affect their capacity to form a NatB complex with NAA25, and in vitro acetylation assays revealed reduced catalytic activities toward different NatB substrates (PMID 34230638). Children from these two families had developmental delay, intellectual disability (mild to moderate family 1, severe family 2).
The two children in family 1 in this study had a head circumcernces of -2.3 & -1.9 SD (which is not regarded as severe microcephaly).
The three children from family 2 this study had a head circumcernces of -3.5, -3.0 & -3.5 SD (which is regarded as severe microcephaly). Subtle dysmorphic features were also reported.
Sources: Literature; to: Not associated with a phenotype in OMIM nor Gen2Phen. Two missense variants reported as homozygotes in one family each. In silico predictions and in vitro functional studies provide evidence that these variants will adversely affect their capacity to form a NatB complex with NAA25, and in vitro acetylation assays revealed reduced catalytic activities toward different NatB substrates (PMID 34230638). Children from these two families had developmental delay, intellectual disability (mild to moderate family 1, severe family 2).
The two children in family 1 in this study had a head circumcernces of -2.3 & -1.9 SD (which is not regarded as severe microcephaly).
The three children from family 2 in this study had a head circumcernces of -3.5, -3.0 & -3.5 SD (which is regarded as severe microcephaly). Subtle dysmorphic features were also reported.
Sources: Literature
Intellectual disability - microarray and sequencing v3.1178 NAA20 Sarah Leigh Added comment: Comment on phenotypes: Currently there is no phenotype associated with this gene in OMIM, Gen2Phen or MONDO (13/07/2021).
Intellectual disability - microarray and sequencing v3.1177 NAA20 Sarah Leigh gene: NAA20 was added
gene: NAA20 was added to Intellectual disability. Sources: Literature
Mode of inheritance for gene: NAA20 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: NAA20 were set to 34230638
Phenotypes for gene: NAA20 were set to autosomal recessive developmental delay, intellectual disability, and microcephaly
Review for gene: NAA20 was set to AMBER
Added comment: Not associated with a phenotype in OMIM nor Gen2Phen. Two missense variants reported as homozygotes in one family each. In silico predictions and in vitro functional studies provide evidence that these variants will adversely affect their capacity to form a NatB complex with NAA25, and in vitro acetylation assays revealed reduced catalytic activities toward different NatB substrates (PMID 34230638). Children from these two families had developmental delay, intellectual disability (mild to moderate family 1, severe family 2).
The two children in family 1 in this study had a head circumcernces of -2.3 & -1.9 SD (which is not regarded as severe microcephaly).
The three children from family 2 this study had a head circumcernces of -3.5, -3.0 & -3.5 SD (which is regarded as severe microcephaly). Subtle dysmorphic features were also reported.
Sources: Literature
Intellectual disability - microarray and sequencing v3.1072 TMEM222 Sarah Leigh edited their review of gene: TMEM222: Added comment: Not associated with relevant phenotype in OMIM or Gen2Phen (TMEM222 not listed on OMIM 11/05/2021). At least ten variants reported in at least nine unrelated families. Moderate to severe intellectual disability was evident in all families.; Changed rating: GREEN
Intellectual disability - microarray and sequencing v3.973 ERBB4 Sarah Leigh edited their review of gene: ERBB4: Added comment: Not associated with relevant phenotype in OMIM or Gen2Phen. PMID 33603162 reports that at least six 2q34 deletions resulting in exon loss in ERBB4 may cause autosomal dominant mild to moderate developmental delay, ID or epilepsy. Rhodent knock out models support this finding (PMID 15219717;30498032).; Changed rating: GREEN; Changed publications: 15219717, 30498032; Changed mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Intellectual disability - microarray and sequencing v3.780 CCDC186 Sarah Leigh changed review comment from: Not associated with relevant phenotype in OMIM or Gen2Phen. At least 2 terminating variants reported in unrelated cases.
Sources: Literature; to: Not associated with a relevant phenotype in OMIM or Gen2Phen. At least 2 terminating variants reported in cases with failure to thrive and developmental delay.
Sources: Literature
Intellectual disability - microarray and sequencing v3.780 CCDC186 Sarah Leigh gene: CCDC186 was added
gene: CCDC186 was added to Intellectual disability. Sources: Literature
watchlist tags were added to gene: CCDC186.
Mode of inheritance for gene: CCDC186 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: CCDC186 were set to 33259146; 28600779
Phenotypes for gene: CCDC186 were set to failure to thrive and developmental delay
Review for gene: CCDC186 was set to AMBER
Added comment: Not associated with relevant phenotype in OMIM or Gen2Phen. At least 2 terminating variants reported in unrelated cases.
Sources: Literature
Intellectual disability - microarray and sequencing v3.764 B4GALNT1 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least eight variants reported in at least eight unrelated cases.
Intellectual disability - microarray and sequencing v3.559 LMNB1 Sarah Leigh changed review comment from: Not associated with relevant phenotype in OMIM (19/11/2020), but as confirmed Gen2Phen gene for LMNB1-associated developmental disorder. At least 7 variants reported in at least 7 unrelated cases. Each variant was associated with intellectual disability and microcephaly (PMID 32910914; 33033404).; to: Not associated with relevant phenotype in OMIM (19/11/2020), but as confirmed Gen2Phen gene for LMNB1-associated developmental disorder. At least 5 variants reported in at least 5 unrelated cases. Each variant was associated with intellectual disability and microcephaly (PMID 32910914; 33033404).
Intellectual disability - microarray and sequencing v3.558 LMNB1 Sarah Leigh edited their review of gene: LMNB1: Added comment: Not associated with relevant phenotype in OMIM (19/11/2020), but as confirmed Gen2Phen gene for LMNB1-associated developmental disorder. At least 7 variants reported in at least 7 unrelated cases. Each variant was associated with intellectual disability and microcephaly (PMID 32910914; 33033404).; Changed rating: GREEN; Changed phenotypes: LMNB1-associated developmental disorder
Intellectual disability - microarray and sequencing v3.549 PIGQ Sarah Leigh edited their review of gene: PIGQ: Added comment: Associated with relevant phenotype in OMIM and as possible Gen2Phen gene for severe early onset epilepsy. At least 11 variants reported in seven unrelated cases of multiple congenital anomalies-hypotonia-seizures syndrome-4 (MCAHS4)(Epileptic encephalopathy, early infantile, 77 618548)(OMIM:618548).; Changed rating: GREEN; Changed phenotypes: OMIM:618548; Changed mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability - microarray and sequencing v3.542 TFE3 Sarah Leigh changed review comment from: Not associated with a relevant phenotype in OMIM, but as a confirmed Gen2Phen gene for X-linked dominant Intellectual disability with pigmentary mosaicism and storage disorder and hemizygous TFE3-related intellectual disability with pigmentary mosaicism. At least 14 variants reported as de novo events in 17 unrelated cases of severe intellectual disability with pigmentary mosaicism and storage disorder-like features (no relevant OMIM or MONDO title as of 16/11/2020).

There is enough evidence for this gene to be rated GREEN at the next major review.; to: Not associated with a relevant phenotype in OMIM, but as a confirmed Gen2Phen gene for X-linked dominant Intellectual disability with pigmentary mosaicism and storage disorder and hemizygous TFE3-related intellectual disability with pigmentary mosaicism. At least 14 variants reported as de novo events in 17 unrelated cases of severe intellectual disability with pigmentary mosaicism and storage disorder-like features (no relevant OMIM or MONDO title as of 16/11/2020).
Intellectual disability - microarray and sequencing v3.541 TFE3 Sarah Leigh changed review comment from: Associated with relevant phenotype in OMIM and as confirmed Gen2Phen gene. At least 14 variants reported as de novo events in 17 unrelated cases of severe intellectual disability with pigmentary mosaicism and storage disorder-like features (no OMIM or MONDO title as of 16/11/2020).

There is enough evidence for this gene to be rated GREEN at the next major review.; to: Not associated with a relevant phenotype in OMIM, but as a confirmed Gen2Phen gene for X-linked dominant Intellectual disability with pigmentary mosaicism and storage disorder and hemizygous TFE3-related intellectual disability with pigmentary mosaicism. At least 14 variants reported as de novo events in 17 unrelated cases of severe intellectual disability with pigmentary mosaicism and storage disorder-like features (no relevant OMIM or MONDO title as of 16/11/2020).

There is enough evidence for this gene to be rated GREEN at the next major review.
Intellectual disability - microarray and sequencing v3.520 AFF3 Sarah Leigh changed review comment from: Not associated with relevant phenotype in OMIM and as probable Gen2Phen gene for Skeletal dysplasia with severe neurological disease. At least 2 variants have been reported in peer reviewed literature, further four variants have been reported in a preprint (July 2019). This preprint has not been published in a peer reviewed (as of 06/08/2020). There are convincing aminal models; to: Not associated with relevant phenotype in OMIM and as probable Gen2Phen gene for Skeletal dysplasia with severe neurological disease. At least 2 variants have been reported in peer reviewed literature, further four variants have been reported in a preprint (July 2019). This preprint has not been published in a peer reviewed (as of 06/08/2020). There are convincing aminal models. If the preprint is peer reviewed and the evidence is relevant, then this gene could be rated green at the next major review (as of 12/11/2020).
Intellectual disability - microarray and sequencing v3.519 AFF3 Sarah Leigh changed review comment from: Not associated with relevant phenotype in OMIM and as probable Gen2Phen gene for Skeletal dysplasia with severe neurological disease. At least 2 variants have been reported in peer reviewed literature, further four variants have been reported in a preprint (July 2019). This preprint has not been published in a peer reviewed (as of 06/08/2020). There are confvincing aminal models; to: Not associated with relevant phenotype in OMIM and as probable Gen2Phen gene for Skeletal dysplasia with severe neurological disease. At least 2 variants have been reported in peer reviewed literature, further four variants have been reported in a preprint (July 2019). This preprint has not been published in a peer reviewed (as of 06/08/2020). There are convincing aminal models
Intellectual disability - microarray and sequencing v3.293 EARS2 Sarah Leigh changed review comment from: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least 15 variants reported in at least 12 unrelated cases, with variable degrees of psycomotor motor delay or regression and little or no language.; to: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least 14 variants reported in at least 11 unrelated cases, with variable degrees of psycomotor motor delay or regression and little or no language.
Intellectual disability - microarray and sequencing v3.292 EARS2 Sarah Leigh changed review comment from: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least 14 variants reported in at least 11 unrelated cases, with variable degrees of psycomotor motor delay or regression and little or no language.; to: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least 15 variants reported in at least 12 unrelated cases, with variable degrees of psycomotor motor delay or regression and little or no language.
Intellectual disability - microarray and sequencing v3.292 EARS2 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least 14 variants reported in at least 11 unrelated cases, with variable degrees of psycomotor motor delay or regression and little or no language.
Intellectual disability - microarray and sequencing v3.244 CNTNAP1 Sarah Leigh changed review comment from: Comment on list classification: Associated with relevant phenotype in OMIM and as probable Gen2Phen gene. At least four variants reported four unrelated cases of Lethal congenital contracture syndrome 7 616286 and seven variants reported in four cases of Hypomyelinating neuropathy, congenital, 3 618186. Both of these conditions include intellectual disability.; to: Comment on list classification: Associated with relevant phenotype in OMIM and as probable Gen2Phen gene for Lethal congenital contracture syndrome 7 61628. At least four variants reported four unrelated cases of Lethal congenital contracture syndrome 7 616286 and seven variants reported in four cases of Hypomyelinating neuropathy, congenital, 3 618186. Both of these conditions include intellectual disability.
Intellectual disability - microarray and sequencing v3.244 CNTNAP1 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as probable Gen2Phen gene. At least four variants reported four unrelated cases of Lethal congenital contracture syndrome 7 616286 and seven variants reported in four cases of Hypomyelinating neuropathy, congenital, 3 618186. Both of these conditions include intellectual disability.
Intellectual disability - microarray and sequencing v3.242 B9D2 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least five variants reported in four unrelated cases. Three of the variants were reported in two unrelated cases of Joubert syndrome 34, which includes intellectual impairment and the remaining three variants were found in two unrelated fetuses with Meckel syndrome 10, with brain malformations.
Intellectual disability - microarray and sequencing v3.241 B9D2 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least five variants reported in four unrelated cases. Three of the variants were reported in two unrelated cases of Joubert syndrome 34, which includes intellectual impairment and the remaining three variants were found in two unrelated fetuses with Meckel syndrome 10, with brain malformations.
Intellectual disability - microarray and sequencing v3.239 TET3 Sarah Leigh changed review comment from: Comment on list classification: Associated with relevant phenotype including mild to severe intellectual disability in OMIM and as probable Gen2Phen gene for TET3 DNA Demethylation Disorder biallelic and TET3 DNA Demethylation Disorder monoallelic. At least 9 variants reported in total, with 5 variants associated with the biallelic version of the condition in 3 unrelated cases and 4 variants associated with the monoallelic version in 4 unrelated cases.; to: Comment on list classification: Associated with relevant phenotype OMIM and as probable Gen2Phen gene for TET3 DNA Demethylation Disorder biallelic and TET3 DNA Demethylation Disorder monoallelic. At least 9 variants reported in total, with 5 variants associated with the biallelic version of the condition in 3 unrelated cases and 4 variants associated with the monoallelic version in 4 unrelated cases. Mild to severe intellectual disability was reported in 2 unrelated cases of monoallelic and 2 unrelated cases of biallelic 2 cases TET3 DNA Demethylation Disorder.
Intellectual disability - microarray and sequencing v3.239 TET3 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype including mild to severe intellectual disability in OMIM and as probable Gen2Phen gene for TET3 DNA Demethylation Disorder biallelic and TET3 DNA Demethylation Disorder monoallelic. At least 9 variants reported in total, with 5 variants associated with the biallelic version of the condition in 3 unrelated cases and 4 variants associated with the monoallelic version in 4 unrelated cases.
Intellectual disability - microarray and sequencing v3.238 TET3 Sarah Leigh Added comment: Comment on phenotypes: This recognized as TET3 DNA Demethylation Disorder biallelic and TET3 DNA Demethylation Disorder monoallelic in Gen2Phen (https://www.ebi.ac.uk/gene2phenotype/search?panel=ALL&search_term=TET3#).
Intellectual disability - microarray and sequencing v3.235 SUZ12 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as confirmed Gen2Phen gene. At least 5 variants reported in at least 13 affected individuals from 12 families, of whome 7 had mostly mild intellectual disability.
Intellectual disability - microarray and sequencing v3.234 OXR1 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as probable Gen2Phen gene for Autosomal-Recessive Neurological Disease with Cerebellar Atrophy and Lysosomal Dysfunction. At least 4 variants reported in at least 3 unrelated cases, who all had epilepsy and global developmental delay.
Intellectual disability - microarray and sequencing v3.234 OXR1 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as probable Gen2Phen gene for Autosomal-Recessive Neurological Disease with Cerebellar Atrophy and Lysosomal Dysfunction. At least 4 variants reported in at least 3 unrelated cases, who all had epilepsy and global developmental delay.
Intellectual disability - microarray and sequencing v3.230 SFXN4 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least 5 variants reported in at least 3 unreleated cases, with mild to severe intellectual disability.
Intellectual disability - microarray and sequencing v3.228 MTHFS Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least 4 variants reported in at least 3 unrelated cases.
Intellectual disability - microarray and sequencing v3.170 SEC31A Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. One homozygous terminating variant reported in sibs of consanguineous Bedouin parents, together with a Drosophila model in which loss of sec31a was embryonically lethal and associated with defects in eye and brain development, consistent with abnormal neurodevelopment.
Intellectual disability - microarray and sequencing v3.168 SBF1 Sarah Leigh changed review comment from: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least 7 variants reported in at least 5 unrelated cases.; to: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least 7 variants reported in at least 5 unrelated cases. The phenotypes vary, but early‐onset microcephaly and moderate‐severe developmental delay were reported in 3 cases (PMID 30039846, 21210780, 20658556).
Intellectual disability - microarray and sequencing v3.168 SBF1 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least 7 variants reported in at least 5 unrelated cases.
Intellectual disability - microarray and sequencing v3.166 SARS2 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least 3 variants reported in at least 3 unrelated cases. Segregates with the disease.
Intellectual disability - microarray and sequencing v3.163 RUSC2 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least 2 variants reported in at least 2 unrelated cases. No functional studies have been reported, although authors of PMID 27612186 suggest that p.R866* results in total loss of function as the sibs biallelic with this variant have a more severe phenotype than the case who is biallelic for p.R1318*, which they conclude results in partial loss of function.
Intellectual disability - microarray and sequencing v3.159 GALNT2 Sarah Leigh gene: GALNT2 was added
gene: GALNT2 was added to Intellectual disability. Sources: Literature
for-review tags were added to gene: GALNT2.
Mode of inheritance for gene: GALNT2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: GALNT2 were set to 27508872; 32293671
Phenotypes for gene: GALNT2 were set to Congenital disorder of glycosylation, type IIt 618885
Review for gene: GALNT2 was set to GREEN
Added comment: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least 5 variants reported in at least 5 unrelated cases, together with mouse and rat models (PMID 27508872;32293671).
Sources: Literature
Intellectual disability - microarray and sequencing v3.155 NRROS Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as probable Gen2Phen gene for NRROS-related Infantile-Onset Neurodegeneration with Intracranial Calcification. At least 6 variants reported in at least 5 unrelated cases (PMIDs 32100099;32197075), together with supportive mouse model (PMID 28459434).
Intellectual disability - microarray and sequencing v3.154 NRROS Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as probable Gen2Phen gene for NRROS-related Infantile-Onset Neurodegeneration with Intracranial Calcification. At least 6 variants reported in at least 5 unrelated cases (PMIDs 32100099;32197075), together with supportive mouse model (PMID 28459434).
Intellectual disability - microarray and sequencing v3.153 NOVA2 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as probable Gen2Phen gene. At least 6 terminating variants reported in unrelated cases, together supportive functional studies in a zebrafish knockdown of the NOVA2 ortholog (nova1a) (PMID 32197073).
Intellectual disability - microarray and sequencing v3.152 NOVA2 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as probable Gen2Phen gene. At least 6 terminating variants reported in unrelated cases, together supportive functional studies in a zebrafish knockdown of the NOVA2 ortholog (nova1a) (PMID 32197073).
Intellectual disability - microarray and sequencing v3.150 CDK19 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as probable Gen2Phen gene. At least 2 variants reported in 3 unrelated cases, together with supportive Drosophila, demonstating the effects of the variants (PMID 32330417).
Intellectual disability - microarray and sequencing v3.147 WIPI2 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least 1 homozygous variant was reported in 4 members of a consanguineous family.
Intellectual disability - microarray and sequencing v3.145 GSX2 Sarah Leigh changed review comment from: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least 2 variants reported in at least 2 unrealated cases.; to: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least 2 variants reported in at least 2 unrealated cases, together with supportive functional studies (PMID 31412107).
Intellectual disability - microarray and sequencing v3.145 GSX2 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least 2 variants reported in at least 2 unrealated cases.
Intellectual disability - microarray and sequencing v3.139 RSRC1 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as confirmed Gen2Phen gene. At least 9 variants reported in unrelated families.
Intellectual disability - microarray and sequencing v3.134 RIC1 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as possible Gen2Phen gene. At least one variant reported in numerous members of two families, who shared an autozygous interval, confirming Founder effect (PMID 27878435). Segregation was demonstrated, together with supportive functional and zebra fish model (PMID 31932796).
Intellectual disability - microarray and sequencing v3.134 RIC1 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as possible Gen2Phen gene. At least one variant reported in numerous members of two families, who shared an autozygous interval, confirming Founder effect (PMID 27878435). Segregation was demonstrated, together with supportive functional and zebra fish model (PMID 31932796).
Intellectual disability - microarray and sequencing v3.132 OTUD7A Sarah Leigh Added comment: Comment on list classification: Not associated with phenotype in OMIM or in Gen2Phen, Although the region ISCA-46295-Loss, which encompasses the OTUD7A locus, is associated with seizures 20236110, mental retardation 22775350, dysmorphic features, developmental delay and severe epileptic encephalopathy. PMID 31997314 report a homozygous variant in a case of severe global developmental delay, language impairment and epileptic encephalopathy; segregation and functional studies support this gene disease association.
Intellectual disability - microarray and sequencing v3.123 RBL2 Sarah Leigh Added comment: Comment on list classification: Not associated with phenotype in OMIM or in Gen2Phen. Identified as a candidate gene in PMIDs 32105419; 9806916, with two variants in sibblings.
Intellectual disability - microarray and sequencing v3.122 SOX6 Sarah Leigh Added comment: Comment on list classification: Not associated with relevant phenotype in OMIM and as probable Gen2Phen gene for SOX6-related neurodevelopmental syndrome. At least 17 unrelated cases, with 14 de novo heterozygous variants, a further 2 families where the variant appeared to inherited from the affected father and a single case where the variant was found to be mosaic in the unaffected father.
Intellectual disability - microarray and sequencing v3.121 RBL2 Sarah Leigh Added comment: Comment on list classification: Not associated with phenotype in OMIM or in Gen2Phen. Identified as a candidate gene in PMIDs 32105419; 9806916, with two variants in sibblings.
Intellectual disability - microarray and sequencing v3.120 TTC5 Sarah Leigh Added comment: Comment on list classification: Not associated with a relevant phenotype in OMIM and as probable Gen2Phen gene for TTC5-associated neurodevelopmental disorder. At least 7 cases with biallelic variants.
Intellectual disability - microarray and sequencing v3.119 RBL2 Sarah Leigh Added comment: Comment on list classification: Not associated with phenotype in OMIM or in Gen2Phen. Identified as a candidate gene in PMIDs 32105419; 9806916, with two variants in sibblings.
Intellectual disability - microarray and sequencing v3.110 SLC1A1 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least 2 variants reported in 2 unrelated cases (PMID 21123949), a SLC1A1 null mouse model with age-dependent chronic neurodegeneration (PMID 16311588), together with historic reports of intellectual disability associated with the phenotype (PMID 894411).
Intellectual disability - microarray and sequencing v3.104 PIGS Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as probable Gen2Phen gene. At least 5 variants reported in at least 3 unrelated cases.
Intellectual disability - microarray and sequencing v3.103 PIGS Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as probable Gen2Phen gene. At least 5 variants reported in at least 3 unrelated cases.
Intellectual disability - microarray and sequencing v3.103 PIGS Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as probable Gen2Phen gene. At least 5 variants reported in at least 3 unrelated cases.
THIS GENE COULD BE RATED GREEN AT THE NEXT MAJOR REVIEW
Intellectual disability - microarray and sequencing v3.101 ALG14 Sarah Leigh Added comment: Comment on list classification: Associated with Myasthenic syndrome, congenital, 15, without tubular aggregates 616227 in OMIM, but not associated with phenotype in Gen2Phen. At least 6 variants reported in at least 5 cases with varying phenotypes. PMID 23404334 reports compound heterozygous (p.P65L, P.R104*) sibs, who manifested with myasthenic syndromes, but did not have intellectural disability nor seizures and were 62 and 51 years old when reported. PMID 28733338 reports two compound heterozygous (p.D74N, pV141G), (p.D74N, p.R109Q) cases and a homozygous ((p.D74N), with early and lethal neurodegeneration with myasthenic and myopathic features, but the cases died before intellectual disability was manifiest. However, seizures were evident in two compound heterozygous families. PMID 30221345 reports a homozygous splicing variant in a case with intellectual disability and seizures. Functional studies were presented showing that this variant resulting in exon skipping, however, this was not completely prenetrant as wild type protein was detected at a low level in the patient.
Intellectual disability - microarray and sequencing v3.96 PIGK Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as probable Gen2Phen gene for PIGK-associated Neurodevelopmental Syndrome. At least 10 variants reported in at least 9 unrelated cases.
Intellectual disability - microarray and sequencing v3.95 PIGK Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as probable Gen2Phen gene for PIGK-associated Neurodevelopmental Syndrome. At least 10 variants reported in at least 9 unrelated cases.
Intellectual disability - microarray and sequencing v3.88 CDC42BPB Sarah Leigh changed review comment from: Comment on list classification: Not associated with phenotype in OMIM and as possible Gen2Phen gene. At least 12 variants reported in 14 unrelated cases of CDC42BPB-related Neurodevelopmental Disorder. intellectual disability was apparent in 7/12 cases and at least 5 of these cases were de novo.; to: Comment on list classification: Not associated with phenotype in OMIM and as possible Gen2Phen gene. At least 12 variants reported in 14 unrelated cases of CDC42BPB-related Neurodevelopmental Disorder. Intellectual disability was apparent in 7/12 cases and at least 5 of these cases were de novo. However, only two of these cases did not have additional genetic changes reported.
Intellectual disability - microarray and sequencing v3.88 CDC42BPB Sarah Leigh Added comment: Comment on list classification: Not associated with phenotype in OMIM and as possible Gen2Phen gene. At least 12 variants reported in 14 unrelated cases of CDC42BPB-related Neurodevelopmental Disorder. intellectual disability was apparent in 7/12 cases and at least 5 of these cases were de novo.
Intellectual disability - microarray and sequencing v3.87 CDC42BPB Sarah Leigh Added comment: Comment on phenotypes: CDC42BPB-related Neurodevelopmental Disorder is assigned by Gen2Phen.
Intellectual disability - microarray and sequencing v3.84 C16orf62 Sarah Leigh changed review comment from: Comment on list classification: Not associated with phenotype in OMIM or in Gen2Phen. Two variants have been reported as compound heterozygotes in two sibs with features of 3C/Ritscher-Schinzel syndrome. Functional studies show that loss of VPS35L function results in impared autophagy and VPS35L knockout mouse resulted in early embrionic lethality (PMID 25434475).; to: Comment on list classification: Not associated with phenotype in OMIM or in Gen2Phen. Two variants have been reported as compound heterozygotes in two sibs with features of 3C/Ritscher-Schinzel syndrome. Functional studies show that loss of VPS35L function results in impared autophagy and VPS35L knockout mouse resulted in early embrionic lethality (PMID 31712251).
Intellectual disability - microarray and sequencing v3.82 C16orf62 Sarah Leigh Added comment: Comment on list classification: Not associated with phenotype in OMIM or in Gen2Phen. Two variants have been reported as compound heterozygotes in two sibs with features of 3C/Ritscher-Schinzel syndrome. Functional studies show that loss of VPS35L function results in impared autophagy and VPS35L knockout mouse resulted in early embrionic lethality (PMID 25434475).
Intellectual disability - microarray and sequencing v3.80 SNX27 Sarah Leigh Added comment: Comment on list classification: Not associated with phenotype in OMIM (lasted edited on 05/23/2012) or in Gen2Phen. However, five variants in three unrelated cases, together with supportive functional studies and mouse model.
Intellectual disability - microarray and sequencing v3.79 SLC5A6 Sarah Leigh Added comment: Comment on list classification: Not associated with phenotype in OMIM and as possible Gen2Phen gene for SLC5A6-related Neurodevelopmental Disorder. At least 5 variants published in three unrelated famililies (4 cases total) with SLC5A6-related Neurodevelopmental Disorder, together with supportive functional studies (PMID 29669219; 23104561). One of the cases had mixed semiology seizures including focal dyscognitive, absence, tonic spasms and generalised convulsive seizures with electrographic features of encephalopathy with generalised and independent multifocal spike-wave discharges (PMID 31754459), another case had brain, immune, bone and intestinal dysfunction (PMID 27904971) and the third had metabolic dysfunction mimicking biotinidase deficiency (PMID 31392107). This condition could be treated with biotin supplementation and introduction of pantothenic acid supplementation (PMID 31392107).
Intellectual disability - microarray and sequencing v3.23 RNF13 Sarah Leigh changed review comment from: Associated with relevant phenotype in OMIM and as probable Gen2Phen gene. At least 2 variants reported in 3 unrelated cases, together with supportive functional studies.; to: Associated with relevant phenotype in OMIM and as probable Gen2Phen gene. At least 2 variants reported in 3 unrelated cases, together with supportive functional studies.

Gain-of-function mechanism has been reported, therefore the mutational spectrum may be limited and is still to be determined through further cases or further functional studies (view of Helen Britain, GeL Clincial Fellow).
Intellectual disability - microarray and sequencing v3.23 SCAMP5 Sarah Leigh changed review comment from: Comment on list classification: Not associated with phenotype in OMIM (last edited on 10/06/2014) or in Gen2Phen. Two variants have been identified in three unrelated cases (one monoallelic, one biallelic). Supportive functional studies have been reported.
It would appear that the two variants reported so far in this gene result in differing mode of pathogenicity and phenotypic features. With heterozygous c.538G>T, p.Gly180Trp seeming to have a dominant-negative effect resulting in autistic spectrum disorder, intellectual disability and seizures. While homozygous c.271C>T, p.R91W seems to have a loss of function effect resulting in early onset epilepsy and Parkinson’s disease. This may be due to different functional domains of the mature protein being altered.; to: Comment on list classification: Not associated with phenotype in OMIM (last edited on 10/06/2014) or in Gen2Phen. Two variants have been identified in three unrelated cases (one monoallelic, one biallelic). Supportive functional studies have been reported.
It would appear that the two variants reported so far in this gene result in differing mode of pathogenicity and phenotypic features. With heterozygous c.538G>T, p.Gly180Trp seeming to have a dominant-negative effect resulting in autistic spectrum disorder, intellectual disability and seizures. While homozygous c.271C>T, p.R91W seems to have a loss of function effect resulting in early onset epilepsy and Parkinson’s disease. This may be due to different functional domains of the mature protein being altered.
Based on this evidence, SCAMP5 is rated as Amber, with a Watchlist tag. This status may change if further cases are reported.
Intellectual disability - microarray and sequencing v3.18 SCAMP5 Sarah Leigh Added comment: Comment on list classification: Not associated with phenotype in OMIM (last edited on 10/06/2014) or in Gen2Phen. Two variants have been identified in three unrelated cases (one monoallelic, one biallelic). Supportive functional studies have been reported.
It would appear that the two variants reported so far in this gene result in differing mode of pathogenicity and phenotypic features. With heterozygous c.538G>T, p.Gly180Trp seeming to have a dominant-negative effect resulting in autistic spectrum disorder, intellectual disability and seizures. While homozygous c.271C>T, p.R91W seems to have a loss of function effect resulting in early onset epilepsy and Parkinson’s disease. This may be due to different functional domains of the mature protein being altered.
Intellectual disability - microarray and sequencing v3.15 RNF113A Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as possible Gen2Phen gene for X-linked trichothiodystrophy. At least 3 terminating variants reported in unrelated cases. Supportive functional studies also reported.
Intellectual disability - microarray and sequencing v3.13 RARS Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as confirmed Gen2Phen gene. At least 19 variants reported in at least 13 cases of Hypomyelinating Leukodystrophy exhibinting intellectual disability to varying degrees. Supportive functional studies were also reported.
Intellectual disability - microarray and sequencing v3.12 RALGAPA1 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM and as probable Gen2Phen gene for RALGAPA1-related neurodevelopmental disorder. At least 5 variants reported in at least 4 unrelated cases.
Intellectual disability - microarray and sequencing v3.10 PUM1 Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least 3 SNVs in at least 5 unrelated cases and CNVs spanning PUM1 in 9 cases. Supportive functional studies also reported.
Intellectual disability - microarray and sequencing v3.7 PIGP Sarah Leigh Added comment: Comment on list classification: Associated with relevant phenotype in OMIM, but not associated with phenotype in Gen2Phen. At least 2 variants reported (rs768633670, rs778481061). rs768633670 were reported as a compound heterozygotes in one case and was present in at least two geographically separated consanguineous European families; suggesting a founder effect in the European population (PMID 32042915).
Supportive functional studies are also presented.
Intellectual disability - microarray and sequencing v3.0 SUPT16H Konstantinos Varvagiannis gene: SUPT16H was added
gene: SUPT16H was added to Intellectual disability. Sources: Literature
Mode of inheritance for gene: SUPT16H was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: SUPT16H were set to http://dx.doi.org/10.1136/jmedgenet-2019-106193
Phenotypes for gene: SUPT16H were set to Global developmental delay; Intellectual disability; Abnormality of the corpus callosum
Penetrance for gene: SUPT16H were set to Complete
Review for gene: SUPT16H was set to AMBER
Added comment: Bina et al (2020 - http://dx.doi.org/10.1136/jmedgenet-2019-106193) report on 4 unrelated individuals with heterozygous SNVs affecting SUPT16H as well as 1 further with microdeletion spanning this gene.

The phenotype consisted of DD with subsequent ID in a subset of them (ages of the cohort: 2y-14y), autistic features in few, abnormalities of the corpus callosum (for 3 with available MRI images), variable gastrointestinal problems in some, and possibly minor dysmorphic features.

SUPT16H encodes a subunit of the FACT (facilitates chromatin transcription) complex, a chromatin-specific factor required for transcription elongation as well as for DNA replication and repair (OMIM citing Belotserkovskaya et al. 2003 - PMID: 12934006). The 2 subunits of the complex [Spt16 (encoded by SUPT16H) and SSRP1] are essential for histone regulation. As the authors note, Spt16 interacts with the histone dimer H2A-H2B during transcription to allow RNA polymerase access to previously coiled DNA [cited PMIDs : 9489704, 10421373 / A recent study by Liu et al 2019 (PMID: 31775157) appears highly relevant].

SUPT16H has a Z-score of 5.1 in gnomAD and a pLI of 1 (%HI of 22.56 in Decipher).

SNVs :
4 de novo missense SNVs were identified following exome sequencing (NM_007192.3:c.484A>G or I162V / L432P / N571S / R734W), all absent from gnomAD and mostly predicted to be deleterious (I162V predicted benign, tolerated, disease-causing by PolyPhen2, SIFT, MutationTaster respectively and had a CADD score of 13.61). Prior work-up for these individuals (incl. CMA in some / MS-MLPA for Angelman s. in 1 / metabolic investigations) had (probably) not revealed an apparent cause, with small CNVs inherited from healthy parents (a 4q13.3 dup / 20q13.2 del - coordinates not provided).

There were no studies performed for the identified variants.

CNVs :
A 5th individual reported by Bina et al was found to harbor a 2.05 Mb 14q11.2 deletion spanning SUPT16H. The specific deletion also spanned CHD8 while the same individual harbored also a 30.17 Mb duplication of 18p11.32q12.1.

CNVs spanning SUPT16H reported to date, also span the (very) proximal CHD8. [Genomic coordinates (GRCh38) for SUPT16H and CHD8 as provided by OMIM : 14:21,351,471-21,384,018 / 14:21,385,198-21,456,122]. Haploinsufficiency of CHD8 is associated with a distinctive syndrome with overgrowth and ID (Douzgou et al 2019 - PMID: 31001818). The phenotype of SUPT16H-CHD8 duplications is discussed in other studies/reviews. [Smol et al 2020 - PMID: 31823155 / Smyk et al 2016 - PMID: 26834018].

Animal models were not commented on by Bina et al (possibly not available for mouse : http://www.informatics.jax.org/marker/MGI:1890948 / https://www.mousephenotype.org/data/genes/MGI:1890948 ).
Sources: Literature
Intellectual disability - microarray and sequencing v2.1047 METTL5 Konstantinos Varvagiannis gene: METTL5 was added
gene: METTL5 was added to Intellectual disability. Sources: Literature
Mode of inheritance for gene: METTL5 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: METTL5 were set to 29302074; http://doi.org/10.1016/j.ajhg.2019.09.007; https://imgc2019.sciencesconf.org/data/abstract_book_complete.pdf
Phenotypes for gene: METTL5 were set to Delayed speech and language development; Intellectual disability; Microcephaly; Behavioral abnormality
Penetrance for gene: METTL5 were set to Complete
Review for gene: METTL5 was set to GREEN
Added comment: [1] - PMID: 29302074 :
In a WES/WGS study of 404 consanguineous families with two or more offspring affected by ID, Hu et al. identified two sibs homozygous for a METTL5 missense variant [NM_014168:c.182G>A / p.Gly61Asp]. These 2 subjects, born to first cousin parents from Iran, presented with early learning impairment, aggressive behaviour, severe microcephaly (-7SD and -8SD) and ID formally evaluated to be in the severe range. Sanger confirmation of variants and segregation studies were performed for all available and informative members in families participating in the study. In silico predictions were all in favour of a deleterious effect (PolyPhen2, MutationTaster, SIFT, CADD) and the variant was absent from ExAC. The effect of the specific variant was studied in ref. 2 (below).

[2] - DOI: 10.1016/j.ajhg.2019.09.007 :
Richard et al. (2019) reported on 5 additional individuals from 2 consanguineous families. Common phenotype consisted of speech delay, moderate/severe ID (4/4), microcephaly (4/4 - though milder than in the first report), behavioral problems (ADHD, aggressiveness, autistic feat.) and possibly some overlapping facial features (nose and ear abnormalities). 3 sibs from the 1st family, from Pakistan, were homozygous for a frameshift variant (NM_014167.2:c.344_345delGA / p.Arg115Asnfs*19) while sibs from the 2nd family, from Yemen, were homozygous for p.Lys191Valfs*1 (c.571_572delAA). Confirmation and segregation studies supported a role for the variants.

The authors performed additional studies for METTL5 and all 3 variants reported to date, notably:
- Based on RNA-seq data from the Allen Brain Atlas, METTL5 is expressed in the developing and adult human brain (incl. cerebellar cortex, hippocampus and striatum).
- Immunostaining in mouse brain demonstrated ubiquitous expression (postnatal day 30).
- In rat hippocampal neurons, enrichment of METTL5 was found in the soma, the nucleus and pre- and post- synaptic regions.
- Myc-/GFP-tagged METTL5 wt or mutants were transiently expressed in COS7 cells, and were found in the cytoplasm and nucleus. Levels of the 2 frameshift variants were significantly reduced compared with wt, although this was not the case for Gly61Asp.
- Upon transfection of rat hippocampal neurons, METTL5-GFP tagged wt and mt proteins showed similar localicalization in nucleus and dendrites.
- Western blot on HEK293T cells transfected with Myc-METTL5 wt or mt constructs demonstrated decreased amounts for the frameshift (but not the missense) variants while comparison after addition of a proteasome inhibitor or cyclohexamide suggested that this is not probably due to decreased mutant protein - rather than mRNA (NMD) - stability.
- In zebrafish, morpholino knockdown of mettl5 led to reduced head size and head/body ratio (reproducing the microcephaly phenotype) and curved tails. Forebrain and midbrain sizes were also significantly reduced.

Based on the ACMG criteria, Gly61Asp is classified as VUS (PM2, PP1, PP3) and the frameshift ones as pathogenic (PS3, PM2, PM4, PP1, PP3).

The authors comment that METTL5 is an uncharacterized member of the methyltransferase superfamily (of 33 METTL proteins). Variants in other methyltransferase-like genes (mainly METTL23) have been associated with ID, while various histone-/DNA-/tRNA-/rRNA- methyltransferases such as EHMT1, DNMT3A, NSUN2, FTSJ1, etc have been implicated in ID. Given the role of methyltransferases in neurodevelopment and neuroplasticity, homology comparisons suggesting presence of relevant domain in METTL5 and accumulation of the protein in the nucleus, a role as epigenetic regulator is proposed (see also ref. 3).

[3] - Conference abstract by Helmut et al. ["A novel m6A RNA methyltransferase in mammals - characterization of Mettl5 mutant mice in the German Mouse Clinic" - Oral presentation in the 33rd International Mammalian Genome Conference Sept. 2019 - available at : https://imgc2019.sciencesconf.org/data/abstract_book_complete.pdf ]
The group using an in vitro methyltransferase assay, identified METTL5 as a m6A RNA methyltransferase. Generation of Mettl5-knockout mice using the CRISPR/Cas technology, suggested that homozygous mice are subviable, with lower body mass and abnormal growth of nasal bones in half. Homozygous mice were hypoactive and hypoexploratory during an open field test at the age of 8 weeks, while further alterations were observed in neurological functions. Phenotypic deviations were absent or very mild in heterozygous animals. As a result, the mouse model appeared to recapitulate relevant human phenotypes (microcephaly, ID and growth retardation).

----
There is no associated entry in OMIM (neither for the gene nor for a related disorder). G2P does not list any phenotype for this gene, either.

METTL5 is included in the SysID database as a current primary ID gene (cited: 27457812, 28097321 / Given the shared co-authors with the study by Richard et al. as well as the overlapping variants, these articles probably report on the same individuals recently described in more detail).

The gene is included in gene panels for ID offered by some diagnostic laboratories (eg. GeneDx).
----

Overall, METTL5 could be considered for inclusion in the ID panel probably as green (3 families, 3 variants, segregation, suggested role of the gene, relevant expression patterns, some evidence at the variant-level, zebrafish and mouse models) or amber (underlying effect of Gly61Asp unknown and variant classified as VUS).
Sources: Literature
Intellectual disability - microarray and sequencing v2.1021 MED25 Konstantinos Varvagiannis changed review comment from: Please consider the 2 additional articles by Nair et al. (2019 - DOI: 10.1159/000494465 - PMID: 30800049 & DOI: 10.1159/000501114 - PMID: NA) reporting on 3 individuals from 2 consanguineous Lebanese families. All affected individuals were homozygous for a MED25 missense variant [NM_030973.3:c.518T>C / p.Ile173Thr], possibly a founder mutation in the Lebanese population. The phenotype presented some similarities with the previously described patients. The variant has a very low AF in gnomAD (0.00003470) and was also absent from the Saudi Variant Database. In silico predictions from PolyPhen2, PROVEAN, MutationTaster were suggestive of a probably damaging effect. The individual from the first report (PMID: 30800049) had an additional homozygous COQ8A variant, with some features fitting with the phenotype of AR primary CoQ10 deficiency type 4 and others negating this diagnosis.

MED25 is included in gene panels for ID offered by several diagnostic laboratories (incl. Radboudumc, Victorian Clinical Genetics and many others). It is not however included in the DD panel of G2P.; to: Please consider the 2 additional articles by Nair et al. (2019 - DOI: 10.1159/000494465 - PMID: 30800049 & DOI: 10.1159/000501114 - PMID: NA) reporting on 3 individuals from 2 consanguineous Lebanese families. All affected individuals were homozygous for a MED25 missense variant [NM_030973.3:c.518T>C / p.Ile173Thr], possibly a founder mutation in the Lebanese population. The phenotype presented some similarities with the previously described patients. The variant has a very low AF in gnomAD (0.00003470) and was also absent from the Saudi Variant Database. In silico predictions from PolyPhen2, PROVEAN, MutationTaster were suggestive of a probably damaging effect. The individual from the first report (PMID: 30800049) had an additional homozygous COQ8A variant, with some features fitting with the phenotype of AR primary CoQ10 deficiency type 4 and others negating this (possibly concurrent) diagnosis.

MED25 is included in gene panels for ID offered by several diagnostic laboratories (incl. Radboudumc, Victorian Clinical Genetics and many others). It is not however included in the DD panel of G2P.
Intellectual disability - microarray and sequencing v2.998 NFASC Sarah Leigh Added comment: Comment on list classification: Associated with phenotype in OMIM and not in Gen2Phen. At least 3 variants identified in unrelated cases.
Intellectual disability - microarray and sequencing v2.938 CTBP1 Konstantinos Varvagiannis changed review comment from: 12 individuals with a recurrent missense variant in CTBP1 have been reported, all summarized in the last article:
- Beck et al. 2016 (PMID: 27094857) : 4 individuals
- Sommerville et al. 2017 (PMID: 28955726) : 1 subject
- Beck et al. 2019 (PMID: 31041561) : 7 further individuals

Features included hypotonia, DD/ID, ataxia and tooth enamel defects. The degree of ID - when present - appeared to be highly variable based at least on the first two reports (3 individuals with severe ID, 1 with borderline-normal intellectual functioning, 1 did not exhibit ID) where this feature was further commented on.

A recurrent missense variant was found in all 12 affected individuals [NM_001328.2:c.1024C>T - p.(Arg342Trp) or NM_001012614.1:c.991C>T - p.(Arg331Trp)]. De novo occurrence this SNV was shown for (almost) all individuals, although in one case maternal sequencing reads were compatible with low-level somatic mosaicism (4/75 reads) not detected by Sanger sequencing. The mother of this individual was phenotypically normal. The variant is absent from gnomAD. Several in silico predictions (SIFT, PolyPhen2, MutationTaster, etc) suggest a deleterious effect.

Given recurrence of this specific variant, and presence of LoF ones in healthy individuals (pLI of 0.98 though in gnomAD) Beck et al. suggested a dominant negative or a gain-of-function effect rather than a loss of function mechanism.

Exclusion of alternative causes: was mainly discussed for the subject reported by Sommerville et al., due to the primary suspicion of a mitochondrial disorder (sequencing and research for mtDNA rearrangements, additional analysis of nuclear genes for mitochondrial disorders).

Expression: CTBP1 encodes C-terminal binding protein 1, with expression among others in brain and cerebellum (https://gtexportal.org/home/gene/CTBP1).

Role and Functional studies:
- The major nuclear isoform of CTBP1 (corresponding to NM_001328.2) and of its paralog CTBP2 function as transcriptional regulators (corepressors). The PLDLS(Pro-Leu-Asp-Leu-Ser)-binding cleft domain where this variant lies, acts as a high-affinity protein-binding interface to recruit DNA-binding repressors and chromatin modifying enzymes (PMID: 17967884).
- In a human glioblastoma cell line interaction of various cofactors with (Flag-tagged) CTBP1 was studied by immunoprecitipation with the Flag antibody and subsequent proteomic (LC-MS) analysis. This demonstrated reduced interaction in the case of R342W (compared to wt) with Zn-finger transcription factors, histone deacetylases, histone methyltransferases, histone H3-K4 demethylase etc. Western blot analyses also revealed reduced interaction of the R342W with several CTBP cofactors.
- RNA-seq analysis in glioblastoma cell line revealed similar overall transcriptional profiles between wt and R342W though multiple RNA species showed significant differences (eg. genes involved in the biological processes of mitotic nuclear division, DNA repair, transcription and regulation of transcription among those that were most upregulated and genes involved in brain development among the most downregulated).
- Patient fibroblasts under conditions of glucose deprivation exhibited strikingly more cell death compared to control fibroblasts. Study of mRNA levels of pro-apoptotic genes by q-RT-PCR revealed that Noxa expression under glucose deprivation vs under normal glucose was 8 to 10-fold enhanced for control fibroblasts, but more than 30-fold enhanced in the case patient fibroblasts. Western blot analyses were also in line with this.
- Mitochondrial dysfunction (probably secondary) with evidence of decreased complex I (and complex IV) activities in skeletal muscle was the case for 2 individuals among multiple patients who had muscle biopsies.

Animal models:
- Beck et al. discuss previously published mouse models where Ctbp1/2 both play overlapping transcriptional roles during development. Homozygous deletion of Ctbp2 is embryonically lethal (>E10.5). Homozygous deletion of Ctbp1 results in viable mice with reduced size and lifespan (Cited: Hildebrand et al. 2002 - PMID: 12101226)
- As commented on by Sommerville et al., Ctbp1 knockout in mouse embryonic fibroblasts resulted in elongated mitochondria, abnormal mitochondrial cristae, diminished ATP and O2 consumption and mitochondrial membrane potential.

----
CTBP1 is associated with Hypotonia, ataxia, developmental delay, and tooth enamel defect syndrome (617915) in OMIM. It is not associated with any phenotype in G2P.
Some diagnostic laboratories (eg. GeneDx participating in the first study and others) include this gene in panels for intellectual disability.
----

As a result, CTBP1 can be added in the current panel probably as green.; to: 12 individuals with a recurrent missense variant in CTBP1 have been reported, all summarized in the last article:
- Beck et al. 2016 (PMID: 27094857) : 4 individuals
- Sommerville et al. 2017 (PMID: 28955726) : 1 subject
- Beck et al. 2019 (PMID: 31041561) : 7 further individuals

Features included hypotonia, DD/ID, ataxia and tooth enamel defects. The degree of ID - when present - appeared to be highly variable based at least on the first two reports (3 individuals with severe ID, 1 with borderline-normal intellectual functioning, 1 did not exhibit ID) where this feature was further commented on.

A recurrent missense variant was found in all 12 affected individuals [NM_001328.2:c.1024C>T - p.(Arg342Trp) or NM_001012614.1:c.991C>T - p.(Arg331Trp)]. De novo occurrence this SNV was shown for (almost) all individuals, although in one case maternal sequencing reads were compatible with low-level somatic mosaicism (4/75 reads) not detected by Sanger sequencing. The mother of this individual was phenotypically normal. The variant is absent from gnomAD. Several in silico predictions (SIFT, PolyPhen2, MutationTaster, etc) suggest a deleterious effect.

Given recurrence of this specific variant, and presence of LoF ones in healthy individuals (pLI of 0.98 though in gnomAD) Beck et al. suggested a dominant negative or a gain-of-function effect rather than a loss of function mechanism.

Exclusion of alternative causes: was mainly discussed for the subject reported by Sommerville et al., due to the primary suspicion of a mitochondrial disorder (sequencing and research for mtDNA rearrangements, additional analysis of nuclear genes for mitochondrial disorders).

Expression: CTBP1 encodes C-terminal binding protein 1, with expression among others in brain and cerebellum (https://gtexportal.org/home/gene/CTBP1).

Role and Functional studies:
- The major nuclear isoform of CTBP1 (corresponding to NM_001328.2) and of its paralog CTBP2 function as transcriptional regulators (corepressors). The PLDLS(Pro-Leu-Asp-Leu-Ser)-binding cleft domain where this variant lies, acts as a high-affinity protein-binding interface to recruit DNA-binding repressors and chromatin modifying enzymes (PMID: 17967884).
- In a human glioblastoma cell line interaction of various cofactors with (Flag-tagged) CTBP1 was studied by immunoprecitipation with the Flag antibody and subsequent proteomic (LC-MS) analysis. This demonstrated reduced interaction in the case of R342W (compared to wt) with Zn-finger transcription factors, histone deacetylases, histone methyltransferases, histone H3-K4 demethylase etc. Western blot analyses also revealed reduced interaction of the R342W with several CTBP cofactors.
- RNA-seq analysis in glioblastoma cell line revealed similar overall transcriptional profiles between wt and R342W though multiple RNA species showed significant differences (eg. genes involved in the biological processes of mitotic nuclear division, DNA repair, transcription and regulation of transcription among those that were most upregulated and genes involved in brain development among the most downregulated).
- Patient fibroblasts under conditions of glucose deprivation exhibited strikingly more cell death compared to control fibroblasts. Study of mRNA levels of pro-apoptotic genes by q-RT-PCR revealed that Noxa expression under glucose deprivation vs under normal glucose was 8 to 10-fold enhanced for control fibroblasts, but more than 30-fold enhanced in the case patient fibroblasts. Western blot analyses were also in line with this.
- Mitochondrial dysfunction (probably secondary) with evidence of decreased complex I (and complex IV) activities in skeletal muscle was the case for 2 individuals among multiple patients who had muscle biopsies.

Animal models:
- Beck et al. discuss previously published mouse models where Ctbp1/2 both play overlapping transcriptional roles during development. Homozygous deletion of Ctbp2 is embryonically lethal (>E10.5). Homozygous deletion of Ctbp1 results in viable mice with reduced size and lifespan (Cited: Hildebrand et al. 2002 - PMID: 12101226)
- As commented on by Sommerville et al., Ctbp1 knockout in mouse embryonic fibroblasts resulted in elongated mitochondria, abnormal mitochondrial cristae, diminished ATP and O2 consumption and mitochondrial membrane potential (Cited: Kim and Youn 2009 - PMID: 19136938).

----
CTBP1 is associated with Hypotonia, ataxia, developmental delay, and tooth enamel defect syndrome (617915) in OMIM. It is not associated with any phenotype in G2P.
Some diagnostic laboratories (eg. GeneDx participating in the first study and others) include this gene in panels for intellectual disability.
----

As a result, CTBP1 can be added in the current panel probably as green.
Intellectual disability - microarray and sequencing v2.938 CTBP1 Konstantinos Varvagiannis changed review comment from: 12 individuals with a recurrent missense variant in CTBP1 have been reported, all summarized in the last article:
- Beck et al. 2016 (PMID: 27094857) : 4 individuals
- Sommerville et al. 2017 (PMID: 28955726) : 1 subject
- Beck et al. 2019 (PMID: 31041561) : 7 further individuals

Features included hypotonia, DD/ID, ataxia and tooth enamel defects. The degree of ID - when present - appeared to be highly variable based at least on the first two reports (3 individuals with severe ID, 1 with borderline-normal intellectual functioning, 1 did not exhibit ID) where this feature was further commented on.

A recurrent missense variant was found in all 12 affected individuals [NM_001328.2:c.1024C>T - p.(Arg342Trp) or NM_001012614.1:c.991C>T - p.(Arg331Trp)]. De novo occurrence this SNV was shown for (almost) all individuals, although in one case maternal sequencing reads were compatible with low-level somatic mosaicism (4/75 reads) not detected by Sanger sequencing. The mother of this individual was phenotypically normal. The variant is absent from gnomAD. Several in silico predictions (SIFT, PolyPhen2, MutationTaster, etc) suggest a deleterious effect.

Given recurrence of this specific variant, and presence of LoF ones in healthy individuals (pLI of 0.98 though in gnomAD) Beck et al. suggested a dominant negative or a gain-of-function effect rather than a loss of function mechanism.

Exclusion of alternative causes: was mainly discussed for the subject reported by Sommerville et al., due to the primary suspicion of a mitochondrial disorder (sequencing and research for mtDNA rearrangements, additional analysis of nuclear genes for mitochondrial disorders).

Expression: CTBP1 encodes C-terminal binding protein 1, with expression among others in brain and cerebellum (https://gtexportal.org/home/gene/CTBP1 ).

Role and Functional studies:
- The major nuclear isoform of CTBP1 (corresponding to NM_001328.2) and of its paralog CTBP2 function as transcriptional regulators (corepressors). The PLDLS(Pro-Leu-Asp-Leu-Ser)-binding cleft domain where this variant lies, acts as a high-affinity protein-binding interface to recruit DNA-binding repressors and chromatin modifying enzymes (PMID: 17967884).
- In a human glioblastoma cell line interaction of various cofactors with (Flag-tagged) CTBP1 was studied by immunoprecitipation with the Flag antibody and subsequent proteomic (LC-MS) analysis. This demonstrated reduced interaction in the case of R342W (compared to wt) with Zn-finger transcription factors, histone deacetylases, histone methyltransferases, histone H3-K4 demethylase etc. Western blot analyses also revealed reduced interaction of the R342W with several CTBP cofactors.
- RNA-seq analysis in glioblastoma cell line revealed similar overall transcriptional profiles between wt and R342W though multiple RNA species showed significant differences (eg. genes involved in the biological processes of mitotic nuclear division, DNA repair, transcription and regulation of transcription among those that were most upregulated and genes involved in brain development among the most downregulated).
- Patient fibroblasts under conditions of glucose deprivation exhibited strikingly more cell death compared to control fibroblasts. Study of mRNA levels of pro-apoptotic genes by q-RT-PCR revealed that Noxa expression under glucose deprivation vs under normal glucose was 8 to 10-fold enhanced for control fibroblasts, but more than 30-fold enhanced in the case patient fibroblasts. Western blot analyses were also in line with this.
- Mitochondrial dysfunction (probably secondary) with evidence of decreased complex I (and complex IV) activities in skeletal muscle was the case for 2 individuals among multiple patients who had muscle biopsies.

Animal models:
- Beck et al. discuss previously published mouse models where Ctbp1/2 both play overlapping transcriptional roles during development. Homozygous deletion of Ctbp2 is embryonically lethal (>E10.5). Homozygous deletion of Ctbp1 results in viable mice with reduced size and lifespan (Cited: Hildebrand et al. 2002 - PMID: 12101226)
- As commented on by Sommerville et al., Ctbp1 knockout in mouse embryonic fibroblasts resulted in elongated mitochondria, abnormal mitochondrial cristae, diminished ATP and O2 consumption and mitochondrial membrane potential.

----
CTBP1 is associated with Hypotonia, ataxia, developmental delay, and tooth enamel defect syndrome (617915) in OMIM. It is not associated with any phenotype in G2P.
Some diagnostic laboratories (eg. GeneDx participating in the first study and others) include this gene in panels for intellectual disability.
----

As a result, CTBP1 can be added in the current panel probably as green.
Sources: Literature; to: 12 individuals with a recurrent missense variant in CTBP1 have been reported, all summarized in the last article:
- Beck et al. 2016 (PMID: 27094857) : 4 individuals
- Sommerville et al. 2017 (PMID: 28955726) : 1 subject
- Beck et al. 2019 (PMID: 31041561) : 7 further individuals

Features included hypotonia, DD/ID, ataxia and tooth enamel defects. The degree of ID - when present - appeared to be highly variable based at least on the first two reports (3 individuals with severe ID, 1 with borderline-normal intellectual functioning, 1 did not exhibit ID) where this feature was further commented on.

A recurrent missense variant was found in all 12 affected individuals [NM_001328.2:c.1024C>T - p.(Arg342Trp) or NM_001012614.1:c.991C>T - p.(Arg331Trp)]. De novo occurrence this SNV was shown for (almost) all individuals, although in one case maternal sequencing reads were compatible with low-level somatic mosaicism (4/75 reads) not detected by Sanger sequencing. The mother of this individual was phenotypically normal. The variant is absent from gnomAD. Several in silico predictions (SIFT, PolyPhen2, MutationTaster, etc) suggest a deleterious effect.

Given recurrence of this specific variant, and presence of LoF ones in healthy individuals (pLI of 0.98 though in gnomAD) Beck et al. suggested a dominant negative or a gain-of-function effect rather than a loss of function mechanism.

Exclusion of alternative causes: was mainly discussed for the subject reported by Sommerville et al., due to the primary suspicion of a mitochondrial disorder (sequencing and research for mtDNA rearrangements, additional analysis of nuclear genes for mitochondrial disorders).

Expression: CTBP1 encodes C-terminal binding protein 1, with expression among others in brain and cerebellum (https://gtexportal.org/home/gene/CTBP1).

Role and Functional studies:
- The major nuclear isoform of CTBP1 (corresponding to NM_001328.2) and of its paralog CTBP2 function as transcriptional regulators (corepressors). The PLDLS(Pro-Leu-Asp-Leu-Ser)-binding cleft domain where this variant lies, acts as a high-affinity protein-binding interface to recruit DNA-binding repressors and chromatin modifying enzymes (PMID: 17967884).
- In a human glioblastoma cell line interaction of various cofactors with (Flag-tagged) CTBP1 was studied by immunoprecitipation with the Flag antibody and subsequent proteomic (LC-MS) analysis. This demonstrated reduced interaction in the case of R342W (compared to wt) with Zn-finger transcription factors, histone deacetylases, histone methyltransferases, histone H3-K4 demethylase etc. Western blot analyses also revealed reduced interaction of the R342W with several CTBP cofactors.
- RNA-seq analysis in glioblastoma cell line revealed similar overall transcriptional profiles between wt and R342W though multiple RNA species showed significant differences (eg. genes involved in the biological processes of mitotic nuclear division, DNA repair, transcription and regulation of transcription among those that were most upregulated and genes involved in brain development among the most downregulated).
- Patient fibroblasts under conditions of glucose deprivation exhibited strikingly more cell death compared to control fibroblasts. Study of mRNA levels of pro-apoptotic genes by q-RT-PCR revealed that Noxa expression under glucose deprivation vs under normal glucose was 8 to 10-fold enhanced for control fibroblasts, but more than 30-fold enhanced in the case patient fibroblasts. Western blot analyses were also in line with this.
- Mitochondrial dysfunction (probably secondary) with evidence of decreased complex I (and complex IV) activities in skeletal muscle was the case for 2 individuals among multiple patients who had muscle biopsies.

Animal models:
- Beck et al. discuss previously published mouse models where Ctbp1/2 both play overlapping transcriptional roles during development. Homozygous deletion of Ctbp2 is embryonically lethal (>E10.5). Homozygous deletion of Ctbp1 results in viable mice with reduced size and lifespan (Cited: Hildebrand et al. 2002 - PMID: 12101226)
- As commented on by Sommerville et al., Ctbp1 knockout in mouse embryonic fibroblasts resulted in elongated mitochondria, abnormal mitochondrial cristae, diminished ATP and O2 consumption and mitochondrial membrane potential.

----
CTBP1 is associated with Hypotonia, ataxia, developmental delay, and tooth enamel defect syndrome (617915) in OMIM. It is not associated with any phenotype in G2P.
Some diagnostic laboratories (eg. GeneDx participating in the first study and others) include this gene in panels for intellectual disability.
----

As a result, CTBP1 can be added in the current panel probably as green.
Sources: Literature
Intellectual disability - microarray and sequencing v2.938 CTBP1 Konstantinos Varvagiannis gene: CTBP1 was added
gene: CTBP1 was added to Intellectual disability. Sources: Literature
Mode of inheritance for gene: CTBP1 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: CTBP1 were set to 27094857; 28955726; 31041561
Phenotypes for gene: CTBP1 were set to Generalized hypotonia; Global developmental delay; Intellectual disability; Ataxia; Abnormality of dental enamel
Penetrance for gene: CTBP1 were set to unknown
Mode of pathogenicity for gene: CTBP1 was set to Loss-of-function variants (as defined in pop up message) DO NOT cause this phenotype - please provide details in the comments
Review for gene: CTBP1 was set to GREEN
gene: CTBP1 was marked as current diagnostic
Added comment: 12 individuals with a recurrent missense variant in CTBP1 have been reported, all summarized in the last article:
- Beck et al. 2016 (PMID: 27094857) : 4 individuals
- Sommerville et al. 2017 (PMID: 28955726) : 1 subject
- Beck et al. 2019 (PMID: 31041561) : 7 further individuals

Features included hypotonia, DD/ID, ataxia and tooth enamel defects. The degree of ID - when present - appeared to be highly variable based at least on the first two reports (3 individuals with severe ID, 1 with borderline-normal intellectual functioning, 1 did not exhibit ID) where this feature was further commented on.

A recurrent missense variant was found in all 12 affected individuals [NM_001328.2:c.1024C>T - p.(Arg342Trp) or NM_001012614.1:c.991C>T - p.(Arg331Trp)]. De novo occurrence this SNV was shown for (almost) all individuals, although in one case maternal sequencing reads were compatible with low-level somatic mosaicism (4/75 reads) not detected by Sanger sequencing. The mother of this individual was phenotypically normal. The variant is absent from gnomAD. Several in silico predictions (SIFT, PolyPhen2, MutationTaster, etc) suggest a deleterious effect.

Given recurrence of this specific variant, and presence of LoF ones in healthy individuals (pLI of 0.98 though in gnomAD) Beck et al. suggested a dominant negative or a gain-of-function effect rather than a loss of function mechanism.

Exclusion of alternative causes: was mainly discussed for the subject reported by Sommerville et al., due to the primary suspicion of a mitochondrial disorder (sequencing and research for mtDNA rearrangements, additional analysis of nuclear genes for mitochondrial disorders).

Expression: CTBP1 encodes C-terminal binding protein 1, with expression among others in brain and cerebellum (https://gtexportal.org/home/gene/CTBP1 ).

Role and Functional studies:
- The major nuclear isoform of CTBP1 (corresponding to NM_001328.2) and of its paralog CTBP2 function as transcriptional regulators (corepressors). The PLDLS(Pro-Leu-Asp-Leu-Ser)-binding cleft domain where this variant lies, acts as a high-affinity protein-binding interface to recruit DNA-binding repressors and chromatin modifying enzymes (PMID: 17967884).
- In a human glioblastoma cell line interaction of various cofactors with (Flag-tagged) CTBP1 was studied by immunoprecitipation with the Flag antibody and subsequent proteomic (LC-MS) analysis. This demonstrated reduced interaction in the case of R342W (compared to wt) with Zn-finger transcription factors, histone deacetylases, histone methyltransferases, histone H3-K4 demethylase etc. Western blot analyses also revealed reduced interaction of the R342W with several CTBP cofactors.
- RNA-seq analysis in glioblastoma cell line revealed similar overall transcriptional profiles between wt and R342W though multiple RNA species showed significant differences (eg. genes involved in the biological processes of mitotic nuclear division, DNA repair, transcription and regulation of transcription among those that were most upregulated and genes involved in brain development among the most downregulated).
- Patient fibroblasts under conditions of glucose deprivation exhibited strikingly more cell death compared to control fibroblasts. Study of mRNA levels of pro-apoptotic genes by q-RT-PCR revealed that Noxa expression under glucose deprivation vs under normal glucose was 8 to 10-fold enhanced for control fibroblasts, but more than 30-fold enhanced in the case patient fibroblasts. Western blot analyses were also in line with this.
- Mitochondrial dysfunction (probably secondary) with evidence of decreased complex I (and complex IV) activities in skeletal muscle was the case for 2 individuals among multiple patients who had muscle biopsies.

Animal models:
- Beck et al. discuss previously published mouse models where Ctbp1/2 both play overlapping transcriptional roles during development. Homozygous deletion of Ctbp2 is embryonically lethal (>E10.5). Homozygous deletion of Ctbp1 results in viable mice with reduced size and lifespan (Cited: Hildebrand et al. 2002 - PMID: 12101226)
- As commented on by Sommerville et al., Ctbp1 knockout in mouse embryonic fibroblasts resulted in elongated mitochondria, abnormal mitochondrial cristae, diminished ATP and O2 consumption and mitochondrial membrane potential.

----
CTBP1 is associated with Hypotonia, ataxia, developmental delay, and tooth enamel defect syndrome (617915) in OMIM. It is not associated with any phenotype in G2P.
Some diagnostic laboratories (eg. GeneDx participating in the first study and others) include this gene in panels for intellectual disability.
----

As a result, CTBP1 can be added in the current panel probably as green.
Sources: Literature
Intellectual disability - microarray and sequencing v2.783 TRRAP Konstantinos Varvagiannis gene: TRRAP was added
gene: TRRAP was added to Intellectual disability. Sources: Literature
Mode of inheritance for gene: TRRAP was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: TRRAP were set to 30827496
Phenotypes for gene: TRRAP were set to Global developmental delay; Intellectual disability; Autism; Microcephaly; Abnormal heart morphology; Abnormality of the urinary system; Seizures
Penetrance for gene: TRRAP were set to unknown
Mode of pathogenicity for gene: TRRAP was set to Loss-of-function variants (as defined in pop up message) DO NOT cause this phenotype - please provide details in the comments
Review for gene: TRRAP was set to GREEN
gene: TRRAP was marked as current diagnostic
Added comment: Cogné et al. (DDD study among the co-authors - PMID: 30827496) report on 24 individuals with pathogenic TRRAP variants.

17 different variants were reported. All variants were missense SNVs and on most occasions had occurred as de novo or apparently de novo events (paternity and maternity not checked). On one occasion, a parent was not unavailable although the respective grand-parents were not found to harbor the variant. Parental germline mosaicism explained the occurence of a variant in 2 sibs.

The authors suggest a strong genotype-phenotype correlation. Individuals whose variant localized within the residues 1031-1159 (NM_001244580.1) presented with a syndromic form of ID with additional malformations. ID was a universal feature in this group (for those subjects evaluated). For variants outside this cluster of residues the phenotype was rather that of ASD without ID or isolated ID with or without ASD, albeit with some exceptions (eg. F860L also associated with a syndromic presentation). ID was a feature in the majority of individuals belonging to the latter group (67% - all with DD) or overall irrespective of the variant localization (85% for those evaluated - all with DD).

Epilepsy was a feature in 4 individuals (4/24) belonging to either group.

All 17 variants were absent from gnomAD with CADD scores supporting a deleterious effect (SIFT/PolyPhen2 (both) predicted a tolerated/benign effect for some eg. Ala1043Thr). A few variants were recurrent, namely Ala1043Thr (5 individuals), Glu1106Lys (2), Gly1883Arg (2), Pro1932Leu (in 2 sibs).

6 further subjects (individuals 25-30, reported separately in the supplement) harbored 6 additional variants with lesser evidence for pathogenicity.

TRRAP is among the 5 most intolerant genes to missense mutations (z-score of 10.1 in ExAC) while it is also intolerant to LoF variants (pLI of 1). No deletions have been reported in DECIPHER and no LoF were identified in the study. Given type of variants and their clustering rather a gain-of-function effect or dominant-negative effect is suggested. As the authors note a LoF effect of non-clustering variants, associated with a milder phenotype cannot excluded. [Mode of pathogenicity to change if thought to be useful].

TRRAP encodes a protein involved in the recruitment to chromatin of histone acetyltransferases. The latter control the process of acetylation of lysine residues in histones and other DNA-binding proteins thus playing a major role in regulation of gene expression. In line with this, RNA sequencing analysis in skin fibroblasts from affected subjects demonstrated dysregulation of expression for several genes implicated in neuronal function and ion transport.

As summarized by the authors: In mice, Trapp knockout is embryonically lethal. Brain-specific knockout leads to premature differentiation of neural progenitors and abnormal brain development. Brain atrophy and microcephaly are observed (microcephaly was a feature in some affected individuals as well, primarily those with variants affecting residues 1031-1159). [PMIDs cited: 11544477, 24792116].

De novo TRRAP variants have been reported also in individuals with neuropsychiatric disorders (PMIDs: 21822266, 23042115, 28392909, 30424743) while TRRAP has been classified among the prenatally-biased genes relevant to its brain expression (PMID:23042115).

A de novo missense variant (c.11270G>A or p.R3757Q) was also previously reported in a study of 264 individuals with epileptic encephalopathy (Epi4K Consortium - PMID: 23934111 - indiv. ND29352).
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TRRAP is not associated with any phenotype in OMIM, nor in G2P.
The gene is included in gene panels for ID offered by some diagnostic laboratories (eg. GeneDx participating in the current study).
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As a result, this gene can be considered for inclusion in the ID panel as green (or amber).
Sources: Literature
Intellectual disability - microarray and sequencing v2.588 TSEN15 Konstantinos Varvagiannis gene: TSEN15 was added
gene: TSEN15 was added to Intellectual disability. Sources: Literature,Radboud University Medical Center, Nijmegen
Mode of inheritance for gene: TSEN15 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TSEN15 were set to 27392077; 25558065
Phenotypes for gene: TSEN15 were set to Pontocerebellar hypoplasia, type 2F (MIM 617026)
Penetrance for gene: TSEN15 were set to Complete
Review for gene: TSEN15 was set to GREEN
gene: TSEN15 was marked as current diagnostic
Added comment: Biallelic pathogenic variants in TSEN15 cause Pontocerebellar hypoplasia, type 2F (MIM 617026).

Four individuals with molecular confirmation of the diagnosis, from 3 unrelated consanguineous families have been reported by Breuss et al. (PMID: 27392077). One of these individuals was previously included in a study of neurogenetic disorders in consanguineous families (Alazami et al. - PMID: 25558065). A similarly affected sib (possibly not tested) was reported for one patient.

DD with variable degrees of ID (mild to severe), progressive microcephaly were common to all. Seizures were noted in 2 individuals. MRI images (for the feature of pontocerebellar hypoplasia - PCH) were only available for 2 families.

Affected subjects were homozygous for missense variants private to each family, namely:
- NM_052965.3:c.226T>G (p.Trp76Gly)
- NM_052965.3:c.346C>T (p.His116Tyr)
- NM_052965.3:c.455A>G (p.Tyr152Cys)

Trp76Gly and Tyr152Cys resulted in reduced protein abundance while His116Tyr did not have an effect on TSEN15 expression levels.

TSEN15 is part of the tRNA splicing endonuclease complex, the 3 other components of which (TSEN2, TSEN34, TSEN54) have already been associated with PCH. The complex interacts with an RNA kinase encoded by CLP1.

All 3 variants resulted in altered stoichiometry (/relative abundance) of the 3 other subunits of the complex as well as the relative levels of CLP1.

Almost complete loss of in vitro tRNA cleavage activity was the case for purified complexes from all 3 mutants.
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TSEN15 is included in the DD panel of G2P associated with Pontocerebellar Hypoplasia and Progressive Microcephaly (Disease confidence: probable). ID is among the assigned phenotypes.

This gene is included in gene panels for ID offered by diagnostic laboratories (incl. Radboudumc).
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As a result, TSEN15 could be considered for inclusion in this panel as green (or amber).
Sources: Literature, Radboud University Medical Center, Nijmegen
Intellectual disability - microarray and sequencing v2.556 DPH1 Konstantinos Varvagiannis gene: DPH1 was added
gene: DPH1 was added to Intellectual disability. Sources: Literature,Expert Review
Mode of inheritance for gene: DPH1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: DPH1 were set to 25558065; 26220823; 29362492; 29410513
Phenotypes for gene: DPH1 were set to Developmental delay with short stature, dysmorphic features, and sparse hair, 616901
Penetrance for gene: DPH1 were set to Complete
Review for gene: DPH1 was set to GREEN
gene: DPH1 was marked as current diagnostic
Added comment: Biallelic mutations in DPH1 cause Developmental delay with short stature, dysmorphic features, and sparse hair, MIM 616901.

Overall 11 patients from 6 different families have probably been reported in detail. DD/ID is a universal feature.

In PMID 25558065, Alazami et al. identified 1 patient from the same consanguineous Saudi Arabian family (of 8 total similarly affected individuals) homozygous for the Leu234Pro (NM_001383.3:c.701T>C) variant. This individual was part of a large cohort of patients with neurogenetic disorders from consanguineous families. The phenotype is not described in detail.

In PMID 26220823 Louks et al. report on 4 patients from 3 families belonging to the same genetic isolate from North America and provide details on 4 of the individuals identified by Alazami et al.

The individuals identified in this study were homozygous for Met6Lys which was however predicted to be benign and tolerated (by PolyPhen2 and SIFT respectively) in silico.

DD/ID, unusual skull shape, ectodermal anomalies were universal (8/8) with additional features including short stature (7/8), renal (4/6) or cardiac anomalies (3/8). Some facial features appeared to be common, too.

Functional studies were not performed. However Dph1 pathogenic variants in mice result in restricted growth, craniofacial and developmental defects similar to the human phenotypes (PMIDs 14744934 and 24895408 are cited).

PMIDs 29362492 and 29410513 report on 3 further patients with similar (as well as some additional) features including DD/ID. The individual in the first article was compound heterozygous for a missense (Leu164Pro) and a frameshift variant (c.289delG) while 2 sibs born to consanguineous parents in the second article were homozygous for a frameshift variant (c.1227delG).

The phenotype appears to be consistent among all the published patients.

DPH1 is included in gene panels for intellectual disability offered by different diagnostic laboratories.

As a result, this gene can be considered for inclusion in this panel as green.
Sources: Literature, Expert Review
Intellectual disability - microarray and sequencing v2.468 EN2 Louise Daugherty gene: EN2 was added
gene: EN2 was added to Intellectual disability. Sources: Victorian Clinical Genetics Services
Mode of inheritance for gene: EN2 was set to
Intellectual disability - microarray and sequencing v2.442 PACS2 Sarah Leigh Added comment: Comment when marking as ready: Associated with relevant phenotype in OMIM and as possible Gen2Phen gene. Single de novo variant reported in at least 14 unrelated cases variants (PMID 29656858), together with previous reports of haploinsufficiency encompassing the PACS2 gene
Intellectual disability - microarray and sequencing v2.441 PACS2 Sarah Leigh Added comment: Comment when marking as ready: Associated with relevant phenotype in OMIM and as possible Gen2Phen gene. Single de novo variant reported in at least 14 unrelated cases variants (PMID 29656858), together with previous reports of haploinsufficiency encompassing the PACS2 gene.