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Early onset or syndromic epilepsy v4.85 | 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 |
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Early onset or syndromic epilepsy v4.84 | TMEM63B | Annalisa Vetro reviewed gene: TMEM63B: Rating: ; Mode of pathogenicity: None; Publications: 37421948; Phenotypes: abnormal myelination, developmental and epileptic encephalopathy, hemolytic anemia, infantile spasms; Mode of inheritance: None | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v4.45 | TRA2B |
Achchuthan Shanmugasundram changed review comment from: This gene has already been associated with phenotypes in Gene2Phenotype (with 'moderate' rating in the DD panel), but not in OMIM. Sources: Literature; to: PMID:36549593 reported 12 individuals from 11 unrelated families identified with 11 different heterozygous variants in TRA2B gene. The variants arose de novo in 10 families, while the variant was inherited from father to son in one family. 6 variants were expected to disrupt the translation start site in exon 1 (start-loss variants), 3 were expected to disrupt the splicing process at the exon 2/3 boundary (splice-affecting variants), and the remaining 2 were expected to produce a premature stop codon (truncating variants). These patients presented with a neurodevelopmental disorder comprising developmental delay/ intellectual disability (in all patients), axial or global hypotonia (10 patients), delayed motor milestones (all patients), behavioural issues (8 patients), speech impairment (9 patients), epilepsy (7 patients, initial presentation as infantile spasms in 6 and unclassified epileptic encephalopathy in 1), brain abnormalities (10 patients) and microcephaly (5 patients). In addition, functional studies in mice showed that heterozygous knockout mice developed normal, while complete knockout mice cannot develop embryonically. This gene has already been associated with phenotypes in Gene2Phenotype (with 'moderate' rating in the DD panel), but not in OMIM. Sources: Literature |
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Early onset or syndromic epilepsy v3.64 | SLC39A8 | Sarah Leigh edited their review of gene: SLC39A8: Added comment: Associated with Congenital disorder of glycosylation, type IIn (OMIM:616721) in OMIM and as definitive Gen2Phen gene for Intellectual Disability with Cerebellar Atrophy. At least five SLC39A8 variants have been reported in four unrelated cases of OMIM:616721 where seizures, infantile spasms or epilepsy have been reported (PMID: 26637978; 26637979). Haplotype analysis of the cases reported by PMID: 26637978, confirm that although the cases both were homozygous for the same variant (rs778210210), they were unrelated.; Changed rating: GREEN | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v2.590 | CAPRIN1 |
Konstantinos Varvagiannis gene: CAPRIN1 was added gene: CAPRIN1 was added to Genetic epilepsy syndromes. Sources: Literature Mode of inheritance for gene: CAPRIN1 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown Publications for gene: CAPRIN1 were set to 35979925; 35977029; 28135719; 31398340; https://doi.org/10.1101/2021.12.20.21267194 Phenotypes for gene: CAPRIN1 were set to Global developmental delay; Delayed speech and language development; Intellectual disability; Autistic behavior; Seizures Penetrance for gene: CAPRIN1 were set to Incomplete Review for gene: CAPRIN1 was set to AMBER Added comment: A cohort of 12 individuals harboring pathogenic CAPRIN1 variants is described in a recent report by Pavinato et al (2022 - PMID: 35979925). DD, impaired speech/language development (100%), ID (83%), ASD (67%) and seizures (33%) are part of the phenotype (details below). Enrichment for de novo LGD but also missense variants has also been demonstrated upon meta-analysis of different cohorts of 40,853 individuals with ID (N=31,625) or ASD (N=9,228) as discussed by Jia et al (2022 - PMID: 35977029). Role of the gene: Evidence supports among others, a role for CAPRIN1 in formation RNA-protein (stress) granules through interaction with other relevant proteins (e.g. G3BP1/2, FMRP) and regulation of gene expression (Pavinato et al - PMID: 35979925, Jia et al - PMID: 35977029). Jia et al further demonstrated significant reduction of stress granule formation in CAPRIN1 KO HeLa lines. Following generation of CAPRIN1+/- hiPSC line using CRISPR/Cas9 and differentiation into cortical neurons, Pavinato et al noted, altered neuronal structure, abnormal firing properties as well as increased neuronal degeneration possibly linked to presence of increased Ca+2 signals and increase in reactive oxygen species (ROS). Global de novo protein synthesis in neurons appeared to be impaired. Variant type and inheritance : All individuals reported by Paviato et al harbored pLoF (nonsense, frameshift, splicing and a synonymous variant resulting in abnormal splicing) variants. In most cases variants occurred de novo with the exception of 2 subjects having inherited pLoF variants from their affected/unaffected parent. Expressive variability, reduced penetrance and possibility of - a yet to be proven - sex bias are discussed (9M/3F). Missense variants and enrichment for dn missense SNVs have also been shown in large cohorts. The impact of p.I373K has been studied. Variant effect: pLoF : Pavinato et al demonstrated reduced mRNA and protein levels for the truncating variants, and out-of frame exon skipping for a variant affecting splice donor site and a further SNV affecting the last nucleotide of ex8. Missense SNVs : p.I373K abolished interaction with G3BP1/2 and disrupted stress granule formation in the study by Jia et al demonstrating a role of stress granules in pathogenesis of neurodevelopmental disorders. Animal model: As discussed by Pavinato et al abnormal neuronal structure and firing properties are observed in htz mouse models. Htz mice display features of ASD, difficulties in reversal learning (for ID), sporadic occurrence of seizures. Hearing impairment (as in 2-3 individuals described) due to reduced protection from noise exposure was reported in an ear-conditional ko model. The report by Pavinato et al is summarized below. For the study by Jia et al a summary can by found under the review of UBAP2L. Reports of individuals in the context of larger cohorts were not here reviewed (eg. DDD study 2017, PMID: 28135719 || Ruzzo et al 2019, PMID: 31398340 || Fu et al 2021, https://doi.org/10.1101/2021.12.20.21267194). ---- Pavinato et al (2022 - PMID: 35979925) describe the phenotype associated with heterozygous CAPRIN1 pathogenic variants. Overlapping features incl. impaired speech/language development (100%), ID (83%), ASD (67%), ADHD (82%), seizures (33% or 4/12 : absence seizures in 2, infantile spasms with absence epilepsy, secondary generalized epileptic seizures during sleep). Respiratory problems (50%), limb/skeletal anomalies (50%), feeding difficulties (33%), mild hearing hearing impairment (in 2 or 3). There was no evident dysmorphism, despite few recurrent features. CAPRIN1 encodes cell cycle-associated protein 1. As the authors discuss, the gene is ubiquitously expressed with high expression in brain. The protein is known to interact with other RNA-binding proteins (eg. FMRP, G3BP1) for the formation of ribonucleoparticles / RNA granules. The gene localizes in neuronal RNA granules in dendrites. Previous studies have demonstrated a role in regulation of mRNA translation (acting as translational inhibitor with its overexpression leading to reduced protein synthesis). CAPRIN1 interacts with FMRP and CYFIP1, both also involved in regulation of mRNA translation. One individual with microdeletion (~1.4 Mb spanning 8 genes with CAPRIN1 the only predicted to be haploinsufficient) as well as 11 additional subjects with nonsense/splicing variants were identified, following CMA, ES or GS. [The gene has a pHaplo of 0.98 and pLI of 0.97 (LOEUF 0.31)]. Variants were mostly de novo, although one individual had inherited a nonsense variant from his affected father while one further from her unaffected mother. qRT-PCR showed reduced mRNA levels in patient fibroblasts and PBMCs while cycloheximide treatment in fibroblasts resulted in partial rescue in expression of mutant allele. Western blot in fibroblasts confirmed reduced protein levels. cDNA analysis revealed that c.279+1G>T variant resulted in out-of-frame skipping of ex3, while c.879G>A (last base of ex8) resulted in out-of-frame skipping of ex8 and degradation by NMD, with cycloheximide restoring expression of mutant allele. [ NM_005898.5 ] The authors generated a CAPRIN1+/- hiPSC line using CRISPR/Cas9 and hiPSCs were differentiated into cortical neurons. Htz immature neurons displayed altered neuronal structure, accompanied by reduced neurite length similar to previous observations in mice. Increased neuronal degeneration was observed. Ca+2 signals (described in literature to trigger or contribute to neuronal death) were increased compared to controls. Increase in reactive oxygen species (ROS) following Ca+2 overload was also demonstrated, likely contributing to neuronal death. Given the gene's role in regulation of mRNA translation, the authors assessed global de novo protein synthesis in neurons based on pyromicin incorporation (SUnSET assay) with findings supporting the impact of CAPRIN1 haploinsufficiency. Heterozygous neurons were shown to display abnormal firing properties similar to a previously reported mouse model. Mouse model : apart from the findings discussed above (abnormal neuronal structure and firing properties), heterozygous mice displayed similar features to the cohort described eg. reduced sociability and weaker preference for social novelty (as in ASD), difficulties in reversal learning (for ID), sporadic occurrence of seizures upon Morris water maze/contextual fearing tests and epileptic-like fEPSP after LTP. Breathing problems were noted in Carpin1-/- mice. Ear conditional ko was associated with early-onset progressive hearing loss and reduced protection from noise exposure which might be in line with few individuals with hearing impairment. Sources: Literature |
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Early onset or syndromic epilepsy v2.590 | UBAP2L |
Konstantinos Varvagiannis gene: UBAP2L was added gene: UBAP2L was added to Genetic epilepsy syndromes. Sources: Literature Mode of inheritance for gene: UBAP2L was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown Publications for gene: UBAP2L were set to 35977029 Phenotypes for gene: UBAP2L were set to Delayed speech and language development; Motor delay; Intellectual disability; Autistic behavior; Seizures; Microcephaly; Abnormality of head or neck; Short stature; Abnormality of the skeletal system Penetrance for gene: UBAP2L were set to unknown Review for gene: UBAP2L was set to AMBER Added comment: Seizures have been reported in several individuals although a formal diagnosis of epilepsy was retained in ~30% in a small cohort discussed below. Consider inclusion with amber rating. ----- Based on Jia et al (2022 - PMID: 35977029) speech, motor delay as well as ID are observed in individuals harboring de novo pLoF variants in UBAP2L. The gene encodes a regulator of the stress granule (SG) assembly. Extensive evidence is provided on the effect of variants as well as the role of UBAP2L and other genes for components and/or regulation of SG in pathogenesis of NDDs. Among others a Ubap2l htz deletion mouse model (behavioral and cognitive impairment, abnormal cortical development due to impaired SG assembly, etc). Data from 26 previous studies, aggregating 40,853 probands with NDDs (mostly DD/ID, also ASD) suggest enrichment for DNMs in UBAP2L or other genes previously known and further shown to be important for SG formation (incl. G3BP1/G3BP2, CAPRIN1). Details provided below. Not associated with any phenotype in OMIM, G2P or SysNDD. -------- Jia et al (2022 - PMID: 35977029) describe 12 affected individuals with heterozygous de novo pLoF variants in UBAP2L. Phenotype: Features included hypotonia, speech (11/11) and motor delay (8/12), ID (8/10 with formal evaluation), variable behavioral concerns (ADHD 5/11, ASD in 4/10, etc). Seizures were reported in 7/12 with 3/10 having a formal diagnosis of epilepsy. Few had microcephaly (3/10). Facial dysmorphisms were common (9/9) and included abnormal palpebral fissures, deep prominent concha, high broad forehead, hypertelorism, thin upper lip and mild synophrys (each in 4 or less individuals). Short stature or skeletal alterations were described in some (4/10 each). Role of the gene: UBAP2L encodes an essential regulator of stress granule assembly. Stress granules are membraneless cytoplasmic compartments in eukaryotic cells, induced upon a variety of stressors and playing a role in regulation of gene expression. Variants identified : 9 nonsense/frameshift UBAP2L variants and 3 splicing ones were reported, in all cases as de novo events, upon trio/quad exome sequencing. All were absent from gnomAD. There were no other causative variants. Variant effect/studies (NM_014847.4 / NP_055662.3) : - Minigene assays revealed that the 3 splice variants all resulted in out-of-frame exon skipping. - In patient fibroblasts one of these splice variants was demonstrated to result to reduced protein levels. - 8 of the 9 nonsense/frameshift variants were predicted to result to NMD. - 1 nonsense variant (c.88C>T/p.Q30*) was shown to result to decreased protein expression in patient fibroblasts, with detection of the protein using an antibody for the C terminus but not the N terminus. Protein N-terminal sequencing confirmed that the protein lacked the N terminus, with utilization of an alternative start site (11 codons downstream). - Generation of HeLa UBAP2L KO cell lines resulted in significant reduction of SG numbers which was also the case for 4 variants studied, under stress conditions. - The protein has a DUF domain (aa 495-526) known to mediate interaction of UBAP2L with G3BP1 (a stress granule marker) with deletions of this domain leading to shuttling of UBAP2L from the cytoplasm to the nucleus. Truncating variants upstream of the DUF domain were shown to result in nuclear localization. Mouse model : - The authors generated Ubap2l KO model with hmz deletion of Ubap2l resulting in a lethal phenotype (2.6% survived) and htz deletion leading to behavioral issues (low preference for social novelty, anxious-like behaviors) and cognitive impairment. - Ubap2l haploinsufficiency resulted in abnormal cortical development and lamination with reduction of neural progenitor proliferation. - Ubap2l deficiency was shown to impair SG assembly during cortical development both under physiological stress conditions or upon utilization of an oxidative stress inducer. Additional evidence of UBAP2L and SG overall in pathogenesis of NDDs: - Based on DNMs from 40,853 individuals with NDDs from 26 studies (9,228 with ASD, 31,625 with DD/ID) the authors demonstrate significant excess of DNM in 31 genes encoding SG components, regulators or both, the latter being the case for UBAP2L and 2 further genes (G3BP1 and G3BP2 - both with crucial roles in SG assembly). - Excess dn splice-site (N=3) and missense (N=5) variants in G3BP1 were observed in the above cohort [c.95+1G>A, c.353+1G>T, c.539+1G>A / p.S208C, R320C, V366M]. - Excess dn missense (N=7) variants in G3BP2 were observed in the above cohort [p.R13W, D151N, E158K, L209P, E399D, K408E, R438C]. - Generation of G3BP1 or G3BP2 KO HeLa cell lines and immunofluorescence upon use of oxidative stress inducer revealed significant reduction of stress granules. - Generation of HeLa cell lines for 5 G3BP1 mutants (R78C*, R132I*, S208C*, R320C*, V366M) and 7 G3BP2 mutants (p.R13W*, D151N*, E158K, L209P*, E399D, K408E, R438C) revealed that several (those in asterisk) resulted in significantly fewer SG formation under oxidative stress compared to WT while the subcellular distribution of the proteins under stress was identical to WT. - Among the identified genes for SG enriched for DNMs, CAPRIN1 was implicated in previous publications as a NDD risk gene with 3 dn missense SNVs reported (p.I373K, p.Q446H, p.L484P). CAPRIN1 binding to G3BP1/2 has been shown to promote SG formation. Significant reduction of SG was observed in CAPRIN1 KO HeLa lines. p.I373K abolished interaction with G3BP1/2 and disrupted SG formation. Sources: Literature |
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Early onset or syndromic epilepsy v2.571 | RAB11A |
Eleanor Williams changed review comment from: Not associated with a phenotype in OMIM. Has a strong/probable association with 'Epilepsy and intellectual disability' in Gene2Phenotype. PMID: 29100083 - Hamdan et al 2017 - performed WGS on 197 individuals with unexplained Developmental and epileptic encephalopathy and pharmaco-resistant seizures and in their unaffected parents. 2 patients reported with heterozygous missense variants in RAB11A, one of which had seizures (c.244C>T [p.Arg82Cys] variant) in addition to developing severe ID. 2 other individuals with missense variants in RAB11A and some phenotypic data from the DDD project are described but neither had seizures. PMID: 33875846 - Bertoli-Avella et al 2021 - in a large study of patients with no initial diagnostic variants identified by ES/GS, they identified two different heterozygous missense variants in RAB11A in two unrelated patients (NM_004663.4: c.375G>T, p. Lys125Asn and NM_004663.4: c.380A>G, p. Asp127Gly). Little patient information but the patient with the p. Asp127Gly variant is reported to have refractory epileptic spasms. Both had brain anomalies and intellectual disability reported. ; to: Not associated with a phenotype in OMIM. Has a strong/probable association with 'Epilepsy and intellectual disability' in Gene2Phenotype. PMID: 29100083 - Hamdan et al 2017 - performed WGS on 197 individuals with unexplained Developmental and epileptic encephalopathy and pharmaco-resistant seizures and their unaffected parents. 2 patients reported with heterozygous missense variants in RAB11A, one of which had seizures (c.244C>T [p.Arg82Cys] variant) in addition to developing severe ID. 2 other individuals with missense variants in RAB11A and some phenotypic data from the DDD project are described but neither had seizures. PMID: 33875846 - Bertoli-Avella et al 2021 - in a large study of patients with no initial diagnostic variants identified by ES/GS, they identified two different heterozygous missense variants in RAB11A in two unrelated patients (NM_004663.4: c.375G>T, p. Lys125Asn and NM_004663.4: c.380A>G, p. Asp127Gly). Little patient information but the patient with the p. Asp127Gly variant is reported to have refractory epileptic spasms. Both had brain anomalies and intellectual disability reported. |
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Early onset or syndromic epilepsy v2.571 | RAB11A |
Eleanor Williams changed review comment from: Not associated with a phenotype in OMIM. Has a strong/probable association with 'Epilepsy and intellectual disability' in Gene2Phenotype. PMID: 29100083 - Hamdan et al 2017 - performed WGS on 197 individuals with unexplained Developmental and epileptic encephalopathy and pharmaco-resistant seizures and in their unaffected parents. 2 patients reported with heterozygous missense variants in RAB11A, one of which had seizures (c.244C>T [p.Arg82Cys] variant) in addition to developing severe ID. PMID: 33875846 - Bertoli-Avella et al 2021 - in a large study of patients with no initial diagnostic variants identified by ES/GS, they identified two different heterozygous missense variants in RAB11A in two unrelated patients (NM_004663.4: c.375G>T, p. Lys125Asn and NM_004663.4: c.380A>G, p. Asp127Gly). Little patient information but the patient with the p. Asp127Gly variant is reported to have refractory epileptic spasms. Both had brain anomalies and intellectual disability reported. 2 other individuals with missense variants in RAB11A and some phenotypic data from the DDD project are described but neither had seizures.; to: Not associated with a phenotype in OMIM. Has a strong/probable association with 'Epilepsy and intellectual disability' in Gene2Phenotype. PMID: 29100083 - Hamdan et al 2017 - performed WGS on 197 individuals with unexplained Developmental and epileptic encephalopathy and pharmaco-resistant seizures and in their unaffected parents. 2 patients reported with heterozygous missense variants in RAB11A, one of which had seizures (c.244C>T [p.Arg82Cys] variant) in addition to developing severe ID. 2 other individuals with missense variants in RAB11A and some phenotypic data from the DDD project are described but neither had seizures. PMID: 33875846 - Bertoli-Avella et al 2021 - in a large study of patients with no initial diagnostic variants identified by ES/GS, they identified two different heterozygous missense variants in RAB11A in two unrelated patients (NM_004663.4: c.375G>T, p. Lys125Asn and NM_004663.4: c.380A>G, p. Asp127Gly). Little patient information but the patient with the p. Asp127Gly variant is reported to have refractory epileptic spasms. Both had brain anomalies and intellectual disability reported. |
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Early onset or syndromic epilepsy v2.545 | SLC1A2 |
Sarah Leigh changed review comment from: PMID:28915517 reports one case of homozygous c.1421+1G>C in a case of epileptic seizures with visual impairment. The nonconsanguineous German parents of the case, were heterozygous for c.1421+1G>C. The authors observe that haploinsufficiency is not the underlying genetic mechanism in autosomal dominant SLC1A2-related epileptic encephalopathy, they suggest the autosomal dominant variants, which are in between the first two transmembrane domains of the SLC1A2 protein, result in a gain-of-function. In contrast, loss-of-function appears to the mechanism in the homozygous patient; RT-PCR of the patients' fibroblasts revealed two abarrant SLC1A2 products, with deletion of the highly conserverd exon 9 in one and a cryptic splicing product, with termination at p.Leu474 in the other.; to: PMID:28915517 reports one case of homozygous c.1421+1G>C in a case of epileptic seizures with visual impairment. The nonconsanguineous German parents of the case, were heterozygous for c.1421+1G>C. The authors observe that haploinsufficiency is not the underlying genetic mechanism in autosomal dominant SLC1A2-related epileptic encephalopathy, they suggest the autosomal dominant variants, which are in between the first two transmembrane domains of the SLC1A2 protein, result in a gain-of-function, possibly by abnormal channel conductance (PMID: 27445142). In contrast, loss-of-function appears to the mechanism in the homozygous patient; RT-PCR of the patients' fibroblasts revealed two abarrant SLC1A2 products, with deletion of the highly conserverd exon 9 in one and a cryptic splicing product, with termination at p.Leu474 in the other. Clearly further functional studies will be required to clafiry the mechanisms by which SLC1A2 variants result in epilepsy and other phenotypic features. |
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Early onset or syndromic epilepsy v2.524 | DROSHA |
Konstantinos Varvagiannis gene: DROSHA was added gene: DROSHA was added to Genetic epilepsy syndromes. Sources: Literature Mode of inheritance for gene: DROSHA was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown Publications for gene: DROSHA were set to 35405010 Phenotypes for gene: DROSHA were set to Global developmental delay; Intellectual disability; Seizures; Cerebral white matter atrophy; Abnormality of the corpus callosum; Abnormality of movement; Stereotypic behavior; Abnormality of head or neck; Short foot Penetrance for gene: DROSHA were set to unknown Mode of pathogenicity for gene: DROSHA 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: DROSHA was set to AMBER Added comment: Profound DD, ID and seizures have been reported in 2 unrelated subjects with de novo missense variants. The gene has a role in miRNA biogenesis. Both variants described have been shown to have effect on DROSHA's function in Drosophila / C. elegans (partial loss-of-function vs possibility of antimorphic effect discussed || in gnomAD several individuals with LoF alleles / Z=3.98 – pLI : 0.09). There is currently no DROSHA-related phenotype in OMIM, G2P, SysNDD. In PanelApp Australia the gene has amber rating in genetic epilepsy and microcephaly panels (not currently included in the ID one). Consider inclusion in the current panel with amber rating. Also consider inclusion in other possibly relevant panels (given postnatal microcephaly, abn. corpus callosum, progressive white matter atrophy, etc) [ NOT added ] ----- Barish, Senturk, Schoch et al (2022 - PMID: 35405010) describe the phenotype of 2 unrelated individuals with de novo missense DROSHA variants. Features included generalized hypotonia, postnatal microcephaly (-2,6 and -6 SD), feeding difficulties, profound DD and ID, seizures, abnormal movements (choreoathetosis / stereotypic movements), variable respiratory symptoms (in one case episodes of hyperventilation/apnea), cardiovascular or skeletal findings. Brain MRI demonstrated white matter atrophy and thin corpus callosum in both. Brachycephaly with broad face as well as short feet were also among the shared features. Both were investigated by trio ES/GS which were otherwise non diagnostic and without other candidate variants. The 1st individual harbored a de novo htz missense DROSHA variant (c.3656A>G/p.Asp1219Gly) while the 2nd subject had another missense variant (c.4024C>T/p.Arg1342Trp) [NM_013235.4] confirmed by Sanger seq. DROSHA (on 5p13.3) encodes a ribonuclease, subunit of the microprocessor complex, involved in miRNA biogenesis. Specifically, miRNAs are transcribed as part of pri-miRNAs (primary-miRNAs) which are cleaved to pre-miRNAs (precursor-miRNAs) in the nucleus by DROSHA (and its partner DGCR8 or Pasha) and then exported to the cytoplasm for further processing. Cleavage of pre-miRNAs by DICER1 generates mature miRNAs subsequently loaded to the RISC (RNA-induced silencing) complex which uses miRNA as template for recognition and cleavage of complementary mRNA with RNAse. As the authors discuss, miRNA defects have a well-established role in development of model organisms e.g. (several Refs. provided): - in C. elegans miRNA mutants causing lethality, developmental arrest and heterochronicity - in Drosophila playing a role in the development of ovary, eye, nervous system etc. - in mice mRNAs play a role in BMP and TGF-beta signaling while neuronal loss of miRNA processing leads to neurodegeneration/anatomical defects. Feingold syndrome 2 is the single Mendelian disease associated to date with miRNAs, through deletion of a cluster containing 6 MIR genes. miRNA dysregulation is also observed in Rett syndrome - and DROSHA implicated in the pathogenesis of the syndrome - as MECP2 and FOXG1 are cofactors of the microprocessor complex regulating processing of miRNA. One of the individuals here reported had a clinical diagnosis of Rett spectrum while both had overlapping features with Rett s. Studies of DROSHA-dependent miRNAs in fibroblasts from one individual revealed significantly altered expression of mature miRNA (e.g. increased miR98, a miRNA with reduced expression in studies of somatic DROSHA variants) although this was not likely due to processing errors (given only a modest decrease of precursor miRNAs). Previous studies have demonstrated that drosha (the Drosophila ortholog) null mutants die during post-embryonic development with 100% lethality before adulthood (3rd instar larval stage/beginning of pupariation). Mosaic flies with mutant eyes are small-eyed, while viable hypomorphic alleles display synaptic transmission defects (several Refs provided). Here, homozygous flies for null alleles died at the end of 3rd instar larval stage/beginning of pupariation, while loss of drosha resulted in lack of imaginal disc tissue (which surrounds the larval brain) and severely reduced brain size, the latter similar to the microcephaly phenotype. [To the best of my understanding] introduction of a mutated genomic rescue construct (carrying similar substitutions as those observed in human subjects) in eye-specific drosha null (W1123X) flies was partially able to rescue eye/head size for wt or Asp1219Gly (human:Asp1084Gly) suggesting that the latter is a partial LoF allele. Arg1210Trp (corresponding to human Arg1342Trp) was able to rescue the eye phenotype and was not damaging to the function in the specific assay. Drosha expression levels were similar for genomic rescue flies either for wt or for the Asp-Gly variant suggesting that the effect was not due to expression levels (but rather function). Expression of mature miRNAs known to be regulated by Drosha were not affected when comparing wildtype larvae with genomic construct for wt or Asp1084Gly. Upon expression of human cDNA using GAL4/UAS system in drosha mutant (null) eye clones, the reference partially rescued the eye size defect, Asp-Gly behaved as partial loss-of-function allele (~50% function compared to ref), while the Arg-Trp variant was shown to behave as a weaker loss-of-function allele. The authors generated eye-specific drosha mutant clones to study the aging adult eye using ERG recordings. While null mutants display almost no response to light (7- and 20-day old flies), wt genomic rescue was shown to rescue ERG responses, Asp-Gly variant had significant defects (at both 7 and 20 days) and the Arg-Trp had defects approaching statistical significance only at the age of 20 days. Overall these data suggested that Arg-Trp had less severe effect compared to Asp-Gly (as above) while both variants led to progressive neuronal dysfunction. Using CRISPR/Cas9 the authors generated C.elegans knock-ins for a variant analogous to the Asp1219Gly human one. Homozygous animals were inviable at larval stages, displayed a heterochronic phenotype (heterochronicity : development of cells or tissues at an abnormal time relative to other unaffected events in an organism / miRNAs are known to be involved in the heterochronic gene pathway) while this variant was deleterious to the Drosha's ability to process miRNAs. Sources: Literature |
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Early onset or syndromic epilepsy v2.518 | ENTPD1 |
Konstantinos Varvagiannis gene: ENTPD1 was added gene: ENTPD1 was added to Genetic epilepsy syndromes. Sources: Literature Mode of inheritance for gene: ENTPD1 was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: ENTPD1 were set to 35471564; 28742222 Phenotypes for gene: ENTPD1 were set to Spastic paraplegia 64, autosomal recessive, OMIM:615683 Penetrance for gene: ENTPD1 were set to Complete Review for gene: ENTPD1 was set to AMBER Added comment: Biallelic ENTPD1 pathogenic variants cause Spastic paraplegia 64, autosomal recessive (# 615683) with DD/ID being a universal feature as suggested by the study by Calame, Herman et al. Epilepsy was also reported in 7 unrelated individuals so far with supporting evidence also from mouse model. Consider upgrade to green rating in the ID panel, inclusion in the epilepsy panel (amber/green). Also consider adding this gene in panels for white matter disorders (which does not appear to be the case so far). ------- Calame, Herman et al (2022 - PMID:35471564) describe the phenotype of 27 individuals (from 17 unrelated families) with biallelic ENTPD1 pathogenic variants. The authors collected additional information from previously reported cases and summarize the core features of the disorder. As they highlight, the disorder has a childhood onset, with DD/ID as a universal feature (27/27 or 36/36 considering cases from the literature), progressive spastic paraparesis (36/36) [On neurological examination, abnormal reflexes were common with hyperreflexia (8/36), hyporeflexia (5/36), areflexia (3/36) or both hyperreflexia and hypo/areflexia in 20, suggesting mixed upper and lower motor neuron dysfunction]. Other features included dysarthria (in 20/27 or 27/36 overall), white matter abnormalities on brain imaging (12/22 or 15/28, in 12-13 signal abnormalities in posterior limb of internal capsule), or dysmorphisms (13/27). Some individuals had evidence of neurocognitive regression (18/27 or 21/36). Epilepsy was reported in 7 unrelated individuals within the cohort (likely 7/25 as for 2 sibs from Fam11, this was NA). Previous studies had not reported this feature. ENTPD1 encodes ectonucleoside triphosphate diphosphohydrolase 1, involved in hydrolysis of ATP to ADP (and ADP to AMP). While previous studies identified 5 distinct variants (2 missense and 3 pLoF), the authors describe 12 novel variants 10 of which pLoF (stopgain, stoploss, splicing) and 2 missense (one SNV and one MNV). In silico predictions were in favor of a deleterious effect. Almost all variants were ultrarare or absent from gnomAD, although 4 were recurrent ones [NM_001776.6]: c.1109T>A / p.(Leu370*) (possibly recurrent mutation found in 4 families from Persia/Poland), c.574-6_574-3del, c.770_771del / p.(Gly257Glufs*18) (possibly founder allele from the Iberian peninsula), c.1041del / p.(Ile348Phefs*19) (?founder allele in Persia). Variant studies: - c.574-6_574-3del : was shown to result to skipping (complete absence) of exon 6 (RNA extracted from a whole blood sample, followed by cDNA synthesis and Sanger seq using different primer sets). - c.401T>G / p.Met134Arg : RT-qPCR of mRNA from patient lymphoblasts showed significantly reduced mRNA levels in individuals homozygous for this variant. Protein levels were also markedly decreased upon Western blot. ENTPD1 is essential for hydrolysis of ATP to ADP and ADP to AMP, with impairment of ATPase and ADPase activity (significantly decreased phosphate production) in patient lymphoblasts. - c.185T>G / p.Leu62* : As ENTPD1 (also known as CD39) is highly expressed in lymphocytes and polymorphonuclear leukocytes, the authors used flow cytometry on whole blood from individuals hmz for this variant, carrier parents and controls, demonstrating complete absence of ENTPD1 positive cells in affected individuals. Immunohistochemistry for ENTPD1 using paraffin sections of sural nerve demonstrated complete absence of endo and epineural vascular staining (/lack of expression). Untargeted metabolomic analyses were performed in plasma samples from 3 affected individuals. Consistent patterns of metabolic abnormalities with alterations in lipid, nucleotide and carbohydrate metabolism were observed. Some metabolite patterns or biomarkers were indicative of inflammatory state, liver disease, insulin resistance / metabolic syndrome. The authors cite previous mouse models suggesting hepatocellular disfunction, impaired glucose homeostasis and intestinal inflammation in ectonucleotidase deficiency (probably not specific to Entpd1). Further, the authors cite a study by Lanser et al for Entpd1-/- mice exhibiting proepileptogenic activity (2017 - PMID: 28742222 / “Disruption of the ATP/adenosine balance in CD39(-/-) mice is associated with handling-induced seizures”). In vitro studies using a cellular model of sympathetic neurons (nerve growth factor-differentiated PC12 cells) provided evidence that ENTPD1 expression levels modulate exocytic and ischemic neurotransmitter release (cited PMID: 21325440) Overall, the authors propose accessible diagnostic biomarkers for the disorder (e.g. flow cytometry on periperal blood cells, immunochemistry of peripheral nerve biopsies, T2 hyperintense signal in posterior limb of internal capsule, diminished ATP/ADP breakdown in lymphoblast assays, alteration in metabolic pathways) and discuss potential future developments (ASOs for splicing variant, antagonism for purinergic receptor P2X7, etc). Sources: Literature |
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Early onset or syndromic epilepsy v2.489 | CHKA |
Konstantinos Varvagiannis gene: CHKA was added gene: CHKA was added to Genetic epilepsy syndromes. Sources: Literature Mode of inheritance for gene: CHKA was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: CHKA were set to 35202461 Phenotypes for gene: CHKA were set to Abnormal muscle tone; Global developmental delay; Intellectual disability; Seizures; Microcephaly; Abnormality of movement; Abnormality of nervous system morphology; Short stature Penetrance for gene: CHKA were set to Complete Review for gene: CHKA was set to GREEN Added comment: Klöckner (2022 - PMID: 35202461) describe the phenotype of 6 individuals (from 5 unrelated families) harboring biallelic CHKA variants. Shared features incl. abnormal muscle tone(6/6 - hypertonia or hypotonia, 3/6 each), DD/ID (6/6,severe in 4, severe/profound in 2), epilepsy (6/6 - onset: infancy - 3y2m | epileptic spasms or GS at onset), microcephaly (6/6), movement disorders (3/6 - incl. dyskinesia, rigidity, choreoatetotic movements). 2/5 individuals exhibited MRI abnormalities, notably hypomyelination. Short stature was observed in 4/6. Eventual previous genetic testing was not discussed. Exome sequencing (quattro ES for 2 sibs, trio ES for 1 individual, singleton for 3 probands) revealed biallelic CHKA variants in all affected individuals. Sanger sequencing was performed for confirmation and segregation studies. Other variants (in suppl.) were not deemed to be causative for the neurodevelopmental phenotype. 3 different missense, 1 start-loss and 1 truncating variant were identified, namely (NM_0012772.2): - c.421C>T/p.(Arg141Trp) [3 hmz subjects from 2 consanguineous families], - c.580C>T/p.Pro194Ser [1 hmz individual born to consanguineous parents], - c.2T>C/p.(Met1?) [1 hmz individual born to related parents], - c.14dup/p.(Cys6Leufs*19) in trans with c.1021T>C/p.(Phe341Leu) in 1 individual. CHKA encodes choline kinase alpha, an enzyme catalyzing the first step of phospholipid synthesis in the Kennedy pathway. The pathway is involved in de novo synthesis of glycerophospholipids, phosphatidylcholine and phosphatidylethanolamine being the most abundant in eukaryotic membranes. CHKA with its paralog (CHKB) phosphorylates either choline or ethanolamine to phosphocholine or phosphoethanolamine respectively with conversion of ATP to ADP. As the authors comment, biallelic pathogenic variants in CHKB cause a NDD with muscular dystrophy, hypotonia, ID, microcephaly and structural mitochondrial anomalies (MIM 602541). [Prominent mitochondrial patterning was observed in a single muscle biopsy available from an individual with biallelic CHKA variants]. Other disorders of the Kennedy pathway (due to biallelic PCYT2, SELENOI, PCYT1A variants) present with overlapping features incl. variable DD/ID (no-severe), microcephaly, seizures, visual impairment etc. CHKA variants were either absent or observed once in gnomAD, affected highly conserved AAs with multiple in silico predictions in favor of a deleterious effect. In silico modeling suggests structural effects for several of the missense variants (Arg141Trp, Pro194Ser presumably affect ADP binding, Phe341 lying close to the binding site of phosphocholine). Each of the missense variants was expressed in yeast cells and W. Blot suggested expression at the expected molecular weight at comparative levels. The 3 aforementioned variants exhibited reduced catalytic activity (20%, 15%, 50% respectively). NMD is thought to underly the deleterious effect of the frameshift one (not studied). The start-loss variant is expected to result in significantly impaired expression and protein function as eventual utilization of the next possible start codon - occurring at position 123 - would remove 26% of the protein. Chka(-/-) is embryonically lethal in mice, suggesting that complete loss is not compatible with life. Reduction of choline kinase activity by 30% in heterozygous mice did not appear to result in behavioral abnormalities although this was not studied in detail (PMID cited: 18029352). Finally, screening of 1566 mouse lines identified 198 genes whose disruption yields neuroanatomical phenotypes, Chka(+/-) mice being among these (PMID cited: 31371714). There is no associated phenotype in OMIM, Gene2Phenotype or SysID. Overall this gene can be considered for inclusion in the ID and epilepsy panes with green or amber rating (>3 individuals, >3 variants, variant studies, overlapping phenotype of disorders belonging to the same pathway, etc). Consider also inclusion in the microcephaly panel (where available this seemed to be of postnatal onset). Sources: Literature |
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Early onset or syndromic epilepsy v2.331 | NCDN |
Arina Puzriakova gene: NCDN was added gene: NCDN was added to Genetic epilepsy syndromes. Sources: Literature Mode of inheritance for gene: NCDN was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown Publications for gene: NCDN were set to 33711248 Phenotypes for gene: NCDN were set to Intellectual disability; epilepsy Review for gene: NCDN was set to AMBER Added comment: NCDN is not yet associated with any phenotype in OMIM (last edited on 08/08/2012) but in Gene2Phenotype monoallelic disease has a 'probable' confidence rating while biallelic variants have a 'possible' disease confidence rating. - PMID: 33711248 (2021) - Six affected individuals (3 sibs with homozygous missense, and 3 unrelated patients with different de novo missense variants) with variable degrees of DD, ID, and seizures. All 3 sibs had generalised seizures (fever induced in 2), while 2/3 individuals with heterozygous variants developed epileptic spasms presenting several times per day prior to treatment. Supportive functional data included. Sources: Literature |
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Early onset or syndromic epilepsy v2.293 | SATB1 |
Arina Puzriakova gene: SATB1 was added gene: SATB1 was added to Genetic epilepsy syndromes. Sources: Literature Q2_21_rating tags were added to gene: SATB1. Mode of inheritance for gene: SATB1 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown Publications for gene: SATB1 were set to 33513338 Phenotypes for gene: SATB1 were set to Neurodevelopmental disorder Review for gene: SATB1 was set to GREEN Added comment: Currently not associated with any phenotype in OMIM (last edited: 30/09/2020) but has a 'confirmed' disease confidence rating for 'SATB1-related developmental disorder (monoallelic)' in Gene2Phenotype. - Den Hoed et al. 2021 (PMID: 33513338) - Total of 42 individuals from 35 families with SATB1 variants (including previously reported cases) - 30 patients harboured 15 unique SATB1 missense variants, including three recurrent variants; 10 had premature protein truncating variants; and and 2 individuals carried a (partial) gene deletion. 28 variants occurred de novo, 3 were inherited from an affected parent, 5 resulted from suspected parental mosaicism (2 inherited from an unaffected parent indicating reduced penetrance), and unknown inheritance in remaining 4 variants. Phenotypes include neurodevelopmental delay (35/36, 97%), intellectual disability (28/31, 90%), muscle tone abnormalities (abnormal tone 28/37, 76%; hypotonia 28/37, 76%; spasticity 10/36, 28%), epilepsy (22/36, 61%), facial dysmorphisms (24/36, 67%), and dental abnormalities (24/34, 71%). Variable seizure phenotypes described but multiple refractory early-onset cases. Missense variants were associated with a more severe phenotype - for instance, 57% of individuals with a missense variant had severe/profound ID whereas this level of ID was not observed for any individuals with truncating variants. Sources: Literature |
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Early onset or syndromic epilepsy v2.233 | FBXO28 |
Zornitza Stark gene: FBXO28 was added gene: FBXO28 was added to Genetic epilepsy syndromes. Sources: Literature Mode of inheritance for gene: FBXO28 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted Publications for gene: FBXO28 were set to 33280099 Phenotypes for gene: FBXO28 were set to Developmental and epileptic encephalopathy Review for gene: FBXO28 was set to GREEN Added comment: Nine new individuals with FBXO28 pathogenic variants (four missense, including one recurrent, three nonsense, and one frameshift) and all 10 known cases reviewed to delineate the phenotypic spectrum. All had epilepsy and 9 of 10 had DEE, including infantile spasms (3) and a progressive myoclonic epilepsy (1). Median age at seizure onset was 22.5 months (range 8 months to 5 years). Nine of 10 patients had intellectual disability, which was profound in six of nine and severe in three of nine. Movement disorders occurred in eight of 10 patients, six of 10 had hypotonia, four of 10 had acquired microcephaly, and five of 10 had dysmorphic features. Sources: Literature |
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Early onset or syndromic epilepsy v2.202 | ZNF335 |
Arina Puzriakova gene: ZNF335 was added gene: ZNF335 was added to Genetic epilepsy syndromes. Sources: Literature for-review tags were added to gene: ZNF335. Mode of inheritance for gene: ZNF335 was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: ZNF335 were set to 23178126; 27540107; 29652087; 30500859; 31187448 Phenotypes for gene: ZNF335 were set to Microcephaly 10, primary, autosomal recessive, 615095 Review for gene: ZNF335 was set to GREEN Added comment: At least 6 unrelated families reported in literature with different biallelic variants in ZNF335. Microcephaly is the primary feature, but also commonly in association with a variable epilepsy phenotype. Stouffs et al. (PMID:29652087) report 2 unrelated cases: patient A, demonstrating refractory seizures leading to death at age 5 days, whereas patient B lacked any clinical seizures, but had frequent spasms that have yet to be recorded by EEG. The proband in Sato et al. (PMID:27540107) had rare focal seizures controlled by treatment. Although not noted by Yang et al. (PMID:231781260), affected individuals in that family had seizures described as paroxysmal myoclonic jerks (personal communication with Stouffs et al). The case by Rana et al. (PMID:31187448) presented multifocal drug-resistant epilepsy, and while details were limited in McSherry et al. (PMID:30500859), authors did also note seizures. Sources: Literature |
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Early onset or syndromic epilepsy v2.85 | 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 4 variants published in two unrelated famililies (3 cases total) with SLC5A6-related Neurodevelopmental Disorder, together with supportive functional studies. 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). | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v2.56 | ANKRD11 |
Tracy Lester gene: ANKRD11 was added gene: ANKRD11 was added to Genetic epilepsy syndromes. Sources: Expert Review Mode of inheritance for gene: ANKRD11 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted Publications for gene: ANKRD11 were set to 29565525 Phenotypes for gene: ANKRD11 were set to KBG syndrome Penetrance for gene: ANKRD11 were set to Complete Review for gene: ANKRD11 was set to GREEN Added comment: KBG syndrome - EEG abnormalities, with or without seizures, have been reported in about 50% of affected individuals [Skjei et al 2007]. Age of onset can range from infancy to the teenage years [Low et al 2016]. The type of epilepsy is variable. Although tonic-clonic seizures are most common, no one specific type of epilepsy has been associated with the syndrome. Treatment with antiepileptic medication has proven effective in the majority of affected individuals. Many have remission of symptoms after adolescence [Lo-Castro et al 2013]. A few affected individuals have reportedly had severe seizures at a young age (described as infantile spasms / epileptic encephalopathy), in some cases drug resistant [C Ockeloen, personal communication; Samanta & Willis 2015]. - taken from GeneReviews, KBG syndrome, last updated Mar2018. Penetrance of KBG syndrome is thought to be complete, but with variable expressivity. Also associated with 16q24.3 deletions. Sources: Expert Review |
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Early onset or syndromic epilepsy v2.47 | CUL3 |
Konstantinos Varvagiannis gene: CUL3 was added gene: CUL3 was added to Genetic epilepsy syndromes. Sources: Literature Mode of inheritance for gene: CUL3 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown Publications for gene: CUL3 were set to 32341456 Phenotypes for gene: CUL3 were set to Global developmental delay; Intellectual disability; Seizures; Abnormality of cardiovascular system morphology; Abnormality of the palate; Pseudohypoaldosteronism, type IIE - MIM #614496 Penetrance for gene: CUL3 were set to unknown Review for gene: CUL3 was set to AMBER Added comment: Epilepsy has been reported in at least 2 relevant individuals in the literature. -- Nakashima et al (2020 - PMID:32341456) provide clinical details on 3 unrelated individuals with de novo CUL3 variants. Features included DD, variable degrees of ID (P1: severe, P3: mild, P2: NA although he displayed motor and severe speech and language delay and had severe learning difficulties). Two out of three had intractable seizures (onset 2 - 6 months). One presented with congenital heart defects (ASD, PV stenosis) and another submucosal palatoschisis/bifid uvula. There were no facial dysmorphisms reported. CUL3 encodes Cullin-3, a core piece of the E3 ubiquitin ligase complex, thus playing a role in the ubiquitin-proteasome system. [ https://ghr.nlm.nih.gov/gene/CUL3 ]. Germline variants in some other Cullin family genes (eg. CUL4B, CUL7) cause disorders with ID as a feature. The 3 individuals reported by Nakashima had variable previous investigations (karyotype, CMA, metabolic testing) which were non-diagnostic. Singleton or trio exome sequencing identified 2 frameshift and 1 missense variant (NM_003590.4:c.854T>C / p.Val285Ala), further confirmed with Sanger sequencing. De novo occurrence was confirmed by analysis of microsatellite markers in an individual with singleton ES. While the frameshift variants were presumed to lead to NMD (not studied), studies in HEK293T cells suggested that the Val285Ala reduced binding ability with KEAP1, possibly leading to instability of the Cullin-RING ligase (CRL) complex and impairment of the ubiquitin-proteasome system. In OMIM, the phenotype associated with heterozygous CUL3 mutations is Pseudohypoaldosteronism type IIE (PHA2E - # 614496). As OMIM and Nakashima et al comment, PHA2E-associated variants are clustered around exon 9, most lead to skipping of exon 9 and produce an in-frame deletion of 57 aa in the cullin homology domain. Few (probably 3) missense variants in exon 9 have also been reported. Individuals with PHA2E do not display DD/ID and conversely individuals with NDD did not display features of PHA2E. Nakashima et al summarize the phenotypes associated with 12 further de novo CUL3 variants in the literature with most pLOF ones detected in individuals with autism and/or developmental disorders and in few cases with congenital heart disease. Few additional missense variants and a stoploss one have been reported in individuals with NDD and one in SCZ. Heterozygous Cul3 (/tissue-specific) deletion in mice resulted in autism-like behavior. Cul3 deficient mice also demonstrated NMDAR hypofunction and decreased spine density. [PMIDs cited : 31455858, 31780330] Overall haploinsufficiency is favored as the underlying mechanism of variants associated with NDD. Nakashima et al comment that the pathogenesis of missense variants remains unknown and/or that a dominant-negative effect on CRL may be possible. Studies on larger cohorts reporting on individuals with relevant phenotypes due to de novo CUL3 variants (eg. DDD study - PMID: 28135719, Lelieveld et al - PMID: 27479843), are better summarized in denovo-db (after filtering for coding variants): http://denovo-db.gs.washington.edu/denovo-db/QueryVariantServlet?searchBy=Gene&target=cul3 -- Please consider inclusion in other panels if appropriate (e.g. for ASD). Sources: Literature |
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Early onset or syndromic epilepsy v2.10 | RALGAPA1 | Sarah Leigh Added comment: Comment on phenotypes: Intellectual disability;hypotonia;infantile spasms | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v2.10 | RALGAPA1 | Sarah Leigh Phenotypes for gene: RALGAPA1 were changed from Intellectual disability; hypotonia; infantile spasms. to .Neurodevelopmental disorder with hypotonia, neonatal respiratory insufficiency, and thermodysregulation 618797 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v2.0 | RALGAPA1 |
Zornitza Stark gene: RALGAPA1 was added gene: RALGAPA1 was added to Genetic epilepsy syndromes. Sources: Expert list Mode of inheritance for gene: RALGAPA1 was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: RALGAPA1 were set to 32004447 Phenotypes for gene: RALGAPA1 were set to Intellectual disability; hypotonia; infantile spasms. Review for gene: RALGAPA1 was set to GREEN gene: RALGAPA1 was marked as current diagnostic Added comment: Four unrelated individuals reported. Sources: Expert list |
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Early onset or syndromic epilepsy v1.475 | TMX2 |
Konstantinos Varvagiannis gene: TMX2 was added gene: TMX2 was added to Genetic epilepsy syndromes. Sources: Literature Mode of inheritance for gene: TMX2 was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: TMX2 were set to 31586943; 31735293; 31270415 Phenotypes for gene: TMX2 were set to Global developmental delay; Intellectual disability; Seizures; Microcephaly; Abnormal cortical gyration Penetrance for gene: TMX2 were set to Complete Review for gene: TMX2 was set to GREEN Added comment: This gene was reviewed for the intellectual disability panel. Epilepsy is part of the phenotype. Therefore green rating should be considered. From the ID panel : A recent report by Vandervore, Schot et al. following the previous review (Am J Hum Genet. 2019 Nov 12 - PMID: 31735293), provides further evidence that biallelic TMX2 mutations cause malformations of cortical development, microcephaly, DD and ID and epilepsy. As a result this gene should probably be considered for inclusion in the ID/epilepsy panels with green rating. Overall, 14 affected subjects from 10 unrelated families are reported in the aforementioned study. The majority had severe DD/ID (failure to achieve milestones, absent speech/ambulation and signs of cerebral palsy) with few having a somewhat milder impairment. 12 (of the 14) presented with epilepsy (spasms, myoclonic seizures, focal seizures with/without generalization or generalized tonic-clonic seizures) with onset most often in early infancy. Upon brain MRI (in 12 individuals), 5 presented polymicrogyria, 2 others pachygyria, 4 with brain atrophy, etc. All individuals were found to harbor biallelic TMX2 mutations by exome sequencing while previous investigations in several had ruled out alternative causes (infections, metabolic or chromosomal anomalies). Missense variants, an in-frame deletion as well as pLoF (stopgain/frameshift) variants were reported. [NM_015959.3 used as ref below]. The effect of variants was supported by mRNA studies, eg. RT-qPCR/allele specific RT-qPCR. The latter proved reduced expression for a frameshift variant (c.391dup / p.Leu131Profs*6) most likely due to NMD. Total mRNA levels were also 23% lower in an individual compound htz for a missense variant and a stopgain one localized in the last exon (c.757C>T / p.Arg253*). As for the previously reported c.614G>A (p.Arg205Gln), affecting the last nucleotide of exon 6, total mRNA in skin fibroblasts from a homozygous individual was not significantly decreased. RNA-Seq however demonstrated the presence of 4 different transcripts (roughly 25% each), one representing the regular mRNA, one with intron 6 retention (also present at low levels in healthy individuals), one with loss of 11 nucleotides within exon 6 and a fourth one due to in-frame skipping of exon 6. *To the best of my understanding : Thioredoxin (TRX)-related transmembrane proteins (TMX) belong to the broader family of oxidoreductases of protein disulfide isomerase (PDI) having an important role in protein folding. Study of the data from the Allen Human Brain Atlas suggest relevant fetal expression also increasing during postnatal life. As RNA-seq was carried out for 2 individuals, GO analysis suggested that the most deregulated clusters of genes are implicated in post-translational protein modifications (as would be expected for PDIs), membranes and synapse while pathway analysis suggested that relevant categories were inhibited eg. nervous system development/function and cell growth/proliferation/survival. Upon transfection of HEK293T cells, exogenous TMX2 was shown to co-localize with calnexin (CNX) to the (ER) mitochondria-associated-membrane. Mass-spectrometry based analysis of co-immunoprecipitated proteins confirmed interaction with CNX but also other regulators of calcium homeostasis, mitochondrial membrane components and respiratory chain NADH dehydrogenase. Study of the mitochondrial activity of TMX2-deficient fibroblasts suggested reduced respiratory reserve capacity, compensated by increased glycolytic activity. TMX2 occurs in both reduced and oxidized monomeric form. It also forms (homo)dimers with the ratio of dimers/monomers increasing under conditions of oxidative stress. Variant TMX2 increased propensity to form dimers, thus mimicking increased oxidative state. This was observed under stress but also under native conditions. --------- Created: 26 Nov 2019, 11:21 p.m. | Last Modified: 26 Nov 2019, 11:21 p.m. Panel Version: 2.1122 [Previous review] PMID: 31586943 - Ghosh et al. 2019 - reported on 8 individuals from 4 consanguineous families from the Middle East and Central Asia, all with a phenotype of DD/ID, seizures and microcephaly with lissencephaly (microlissencephaly is the term applying to the combination of two) upon brain MRI. All patients were investigated by exome sequencing and the variant localized within a region of ROH which was common to all 4 families. All were homozygous for a TMX2 missense variant (NM_001144012.2:c.500G>A or p.Arg167Gln / NM_015959.4:c.614G>A p.Arg205Gln or hg38 - Chr11:g.57739039G>A). The variant was considered to be the best candidate, upon review of all other homozygous ones. Sanger sequencing confirmed homozygosity for the variant in affected subjects, with additional compatible segregation studies including parents in all families as well as unaffected sibs (in two families). Despite presence of the same mutation in all, several proximal to this variant SNPs did not appear to be shared among the families studied, thus suggesting that the variant had arisen within different haplotype blocks. The authors comment that the variant was not previously identified in public databases. (The variant seems to correspond to rs370455806, present in 10 htz individuals in gnomAD, as well as in the GME database [GME Genotype Count 992:0:1 (hmz?) | Allele Count: 2,1984] . GME includes primarily - although not necessarily - healthy individuals). This SNV affecting the last nucleotide of an exon of several transcripts (correct ref. is NM_001144012.2 as appears in the supplement / using NM_001347898.1 as in the fig./text the variant would lie within an intron), an eventual splicing effect was studied. mRNA transcript levels were assessed following RT-PCR using different sets of primers. There was no evidence of novel splice isoforms but mRNA levels were reduced compared to controls (15-50% in affected individuals, to a lesser level in carriers). This led to the hypothesis that NMD of an aberrantly spliced mRNA might apply, although this was not proven. TMX2 encodes a protein disulfide isomerase (PDI). PDIs are transmembrane ER proteins which have a critical role in protein folding (PMID cited: 12670024). There were no relevant studies carried out in the article. As for animal models, the authors comment that mice homozygous for null mutations display preweaning lethality with complete penetrance.(http://www.informatics.jax.org/diseasePortal/popup?isPhenotype=true&markerID=MGI:1914208&header=mortality/aging). ------- Previously, Schot el al. (ESHG Conference 2018 Oral Presentation - Mutations in the thioredoxin related gene TMX2 cause primary microcephaly, polymicrogyria and severe neurodegeneration with impaired mitochondrial energy metabolism - available in PMID: 31270415 / https://www.nature.com/articles/s41431-019-0407-4 ) reported on 7 individuals from 5 unrelated families with biallelic TMX2 mutations. A newborn with microcephaly, polymicrogyria who died of refractory epilepsy, was compound heterozygous for 2 TMX2 variants. 6 additional individuals (from 4 unrelated families) with similar phenotype were found to harbor biallelic TMX2 mutations. It was commented that TMX2 is enriched in mitochondria-associated membrane of the ER with a role in ER stress protection and regulation of neuronal apoptosis. In line with this, fibroblasts from 2 unrelated patients showed secondary OXPHOS deficiency and increased glycolytic activity (the latter possibly as a compensatory mechanism). ------- There is no associated phenotype in OMIM/G2P/SysID. ------- Overall this gene could be considered for inclusion in the ID/epilepsy panel probably with amber (/red) rating pending further evidence. Sources: Literature Sources: Literature |
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Early onset or syndromic epilepsy v1.411 | GFM1 | Rebecca Foulger commented on gene: GFM1: PMID:28216230 (Simon et al., 2017) report 2 brothers with compound het variants in GFM1 (maternally-inherited p.Arg250Trp and paternally-inherited p.Gly230_231Glnins19). The younger brother (P1) developed seizures by 4.5 months, characterised as infantile spasms. He has remained seizure free on treatment with topiramate. No seizures were noted for the brother who died age 10 months from multiple organ failure. The authors suggest additional modifier genes may be responsible for the different in severity between the brothers. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v1.335 | GABRA5 |
Rebecca Foulger commented on gene: GABRA5: Summary of evidence (see Konstantinos Varvagiannis' reviews for details): 3 literature cases from 2 papers of patients with epileptic encephalopathy and GABRA5 missense variants: PMID:29961870, Butler et al. 2018 report a 2 year old boy with EIEE (seizure onset age 4 months) and a p.V294L variant in GABRA5. Cognitive and motor development slowed at the time of seizure onset. A de novo variant in MIA2 was also detected but was considered unlikely to contribute to the patients phenotypes due to allele frequencies in the gnomAD database. PMID:31056671, Hernandez et al. 2019 screened a cohort of patients with epilepsy and ID and report 2 individuals with EIEE and GABRA5 missense variants (V294F and S413F). Seizures included focal, febrile, focal and tonic, epileptic spasms and status epilepticus. Both had severe ID and delayed motor development. |
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Early onset or syndromic epilepsy v1.301 | AIMP2 | Rebecca Foulger Phenotypes for gene: AIMP2 were changed from Leukodystrophy, hypomyelinating, 17, 618006; neurodevelopmental disorder with microcephaly, seizures, and spastic quadriparesis to Epileptic Encephalopathy; Infantile Spasms; Leukodystrophy, hypomyelinating, 17, 618006; neurodevelopmental disorder with microcephaly, seizures, and spastic quadriparesis | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v1.256 | AIMP2 | Alison Callaway reviewed gene: AIMP2: Rating: AMBER; Mode of pathogenicity: None; Publications: 26795593; Phenotypes: Epileptic Encephalopathy, Infantile Spasms; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v1.193 | GRIA2 |
Konstantinos Varvagiannis gene: GRIA2 was added gene: GRIA2 was added to Genetic epilepsy syndromes. Sources: Literature Mode of inheritance for gene: GRIA2 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown Publications for gene: GRIA2 were set to 31300657 Phenotypes for gene: GRIA2 were set to Intellectual disability; Seizures; Autism Penetrance for gene: GRIA2 were set to unknown Review for gene: GRIA2 was set to AMBER Added comment: There is a recent publication by Salpietro et al. (2019 - PMID: 31300657) reporting on 28 unrelated individuals. Seizures were observed in 12/28 (~40%), so the gene may also be relevant for the current panel. The phenotype overall corresponds to a NDD disorder with DD, ID (universal feature in those with appropriate age for evaluation, relevant severity), ASD, Rett-like features and seizures. All types of variants were reported (15 missense, 2 splice-site, 1 in-frame del, 1 stopgain, 2 frameshift ones, 3 CNVs spanning GRIA2 and other genes, the latter more tolerant to LoF). The role of this gene (encoding AMPA receptor GluA2 subunit), functional studies (loss of function demonstrated for the majority of mutations, though by multiple molecular mechanisms), overlapping phenotype with disorders due to other ionotropic glutamate receptor subunit genes (eg. GRIA3/4 - ID with or without seizures), animal models (PMID cited: 8938126) are among the arguments provided. Sources: Literature |
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Early onset or syndromic epilepsy v1.191 | SMS | Rebecca Foulger Source Wessex and West Midlands GLH was added to SMS. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v1.190 | SMS | Rebecca Foulger Source NHS GMS was added to SMS. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v1.189 | SMS | Rebecca Foulger reviewed gene: SMS: Rating: AMBER; Mode of pathogenicity: ; Publications: ; Phenotypes: ; Mode of inheritance: | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v1.188 | SMS | Tracy Lester reviewed gene: SMS: Rating: GREEN; Mode of pathogenicity: ; Publications: 30237987; Phenotypes: Mental retardation X-linked Snyder-Robinson type, 309583; Mode of inheritance: X-LINKED: hemizygous mutation in males, biallelic mutations in females | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v1.188 | COL4A1 | Tracy Lester reviewed gene: COL4A1: Rating: GREEN; Mode of pathogenicity: ; Publications: 23225343; Phenotypes: Retinal arteries tortuosity of 180000, Angiopathy, hereditary, with nephropathy, aneurysms, and muscle cramps, 611773, Brain small vessel disease with or without ocular anomalies, 607595, Porencephaly, 175780, Schizencephaly 269160; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v1.128 | TRPM3 |
Konstantinos Varvagiannis changed review comment from: Dyment et al. (2019 - https://doi.org/10.1038/s41431-019-0462-x) report on 7 unrelated individuals with a recurrent de novo TRPM3 missense variant [NM_020952.4:c.2509G>A - NP_066003.3:p.(Val837Met)] as well as an additional individual with a further de novo missense variant [c.2810C>A or p.(Pro937Gln) - same ref. sequences]. Overlapping features included hypotonia (7/8 - in one case mixed tone abnormality), DD/ID (8/8 - all individuals at appropriate age - degree relevant), EEG-confirmed epilepsy (7/8). Autism-like features were observed in 4 (out of 6 for whom this information was reported). Other features were noted in a minority (or were private to certain) of these individuals. Different clinical types of seizures were reported incl. absence, generalized-toni-clonic, infantile spasms as well as subclinical ones. Onset was in infancy or early childhood. In all individuals the variant was found following trio exome sequencing. The first variant fulfilled ACMG criteria to be classified as pathogenic due to it's de novo occurrence, prevalence in affected individuals (>=6 affected individuals and in the same time) absence from population databases, in silico predictions in favour of pathogenicity (PS2, PS4_Moderate, PM2, PP3). The Pro937Gln variant is however classified as a VUS. The subject harboring this variant had an additional de novo variant in another gene (DDB1) not associated with any phenotype, to date. Several other genetic causes had previously been ruled out for most individuals by other investigations : aCGH was normal in all, FMR1 testing in 6 subjects, genes (PHF6, MECP2, MCT8) or smaller panels for ID (the latter in 3 subjects), mtDNA or testing of nuclear genes for mitochondrial disorders, etc. TRPM3 encodes transient receptor potential (TRP) cation channel, subfamily M, member 3. TRP channels are a superfamily of gated cation channels sensitive to various physical or chemical stimuli (Clapham 2003 - PMID: 14654832 cited) eg. temperature or pain. The gene is highly expressed in the brain in humans and other vertebrates (Grimm et al. 2003 - PMID : 12672799 and GTEx - https://gtexportal.org/home/gene/TRPM3). Animal models : In rat brain, expression is initially restricted to neurons but later - as myelination progresses - shifts to oligodendrocytes (cited : Hoffmann et al. 2010 - PMID: 20163522). Most subjects had normal brain MRI appart from one individual with nonspecific white matter hyperintensities and another with possible mild cerebral volume loss. Trpm3 -/- mice show attenuated nocifensive behavior after heat or dermal injection of pregnenolone sulfate. Heat or pain insensitivity was reported only for 2 individuals. Functional studies were not carried out, although some hypotheses are proposed following in silico modeling of the TRPM3 variants using an available structure for TRPM7. As discussed by Dyment et al., happloinsufficiency appears to be unlikely given the presence of LoF variants in ExAC/gnomAD (pLI of 0), some intragenic copy number variants in DGV. In addition, pathogenicity of deletions spanning only TRPM3 or additional proximal genes was not evident in 2 cases: - In the first case a exon 1-9 deletion was found in 2 brothers with Becker muscular dystrophy due to DMD intragenic duplication and autism/cognitive impairment though the TRPM3 deletion was found also in unaffected family members. The deletion was also found in unaffected relatives. A multiple hit hypothesis was hypothesized for this family. [Pagnamenta et al. 2011 - PMID: 21484199] - Kuniba et al. [2009 - PMID: 19343044] reported a 1.27-Mb deletion spanning TRPM3, KLF9, SMC5 and MAMDC2 in a patient with Kabuki syndrome working diagnosis. Segregation studies were however not possible. At the time, the molecular etiology of Kabuki syndrome (KMT2D/KDM6A) was not known. ----- TRPM3 is not associated with any phenotype in OMIM or G2P. This gene is included in panels for ID offered by some diagnostic laboratories (eg. GeneDx participating in the above study). ----- As a result, TRPM3 seems to fulfill criteria for inclusion in the ID/epilepsy panels probably as green (# of individuals, degree of ID relevant, EEG-confirmed epilepsy) or amber (if further functional evidence would be required). [Please consider eligibility for inclusion in other possibly relevant panels eg. autism, etc]. Sources: Literature; to: Dyment et al. (2019 - https://doi.org/10.1038/s41431-019-0462-x) report on 7 unrelated individuals with a recurrent de novo TRPM3 missense variant [NM_020952.4:c.2509G>A - NP_066003.3:p.(Val837Met)] as well as an additional individual with a further de novo missense variant [c.2810C>A or p.(Pro937Gln) - same ref. sequences]. Overlapping features included hypotonia (7/8 - in one case mixed tone abnormality), DD/ID (8/8 - all individuals at appropriate age - degree relevant), EEG-confirmed epilepsy (7/8). Autism-like features were observed in 4 (out of 6 for whom this information was reported). Other features were noted in a minority (or were private to certain) of these individuals. Different clinical types of seizures were reported incl. absence, generalized-toni-clonic, infantile spasms as well as subclinical ones. Onset was in infancy or early childhood. In all individuals the variant was found following trio exome sequencing. The first variant fulfilled ACMG criteria to be classified as pathogenic due to it's de novo occurrence, prevalence in affected individuals (>=6 affected individuals and in the same time) absence from population databases, in silico predictions in favour of pathogenicity (PS2, PS4_Moderate, PM2, PP3). The Pro937Gln variant is however also present once in gnomAD (1/251370 alleles or AF:3.98e-6) and is classified as VUS according to the ACMG criteria. The subject harboring this variant had an additional de novo variant in another gene (DDB1) not associated with any phenotype, to date. Several other genetic causes had previously been ruled out for most individuals by other investigations : aCGH was normal in all, FMR1 testing in 6 subjects, genes (PHF6, MECP2, MCT8) or smaller panels for ID (the latter in 3 subjects), mtDNA or testing of nuclear genes for mitochondrial disorders, etc. TRPM3 encodes transient receptor potential (TRP) cation channel, subfamily M, member 3. TRP channels are a superfamily of gated cation channels sensitive to various physical or chemical stimuli (Clapham 2003 - PMID: 14654832 cited) eg. temperature or pain. The gene is highly expressed in the brain in humans and other vertebrates (Grimm et al. 2003 - PMID : 12672799 and GTEx - https://gtexportal.org/home/gene/TRPM3). Animal models : In rat brain, expression is initially restricted to neurons but later - as myelination progresses - shifts to oligodendrocytes (cited : Hoffmann et al. 2010 - PMID: 20163522). Most subjects had normal brain MRI appart from one individual with nonspecific white matter hyperintensities and another with possible mild cerebral volume loss. Trpm3 -/- mice show attenuated nocifensive behavior after heat or dermal injection of pregnenolone sulfate. Heat or pain insensitivity was reported only for 2 individuals. Functional studies were not carried out, although some hypotheses are proposed following in silico modeling of the TRPM3 variants using an available structure for TRPM7. As discussed by Dyment et al., happloinsufficiency appears to be unlikely given the presence of LoF variants in ExAC/gnomAD (pLI of 0), some intragenic copy number variants in DGV. In addition, pathogenicity of deletions spanning only TRPM3 or additional proximal genes was not evident in 2 cases: - In the first case a exon 1-9 deletion was found in 2 brothers with Becker muscular dystrophy due to DMD intragenic duplication and autism/cognitive impairment though the TRPM3 deletion was found also in unaffected family members. The deletion was also found in unaffected relatives. A multiple hit hypothesis was hypothesized for this family. [Pagnamenta et al. 2011 - PMID: 21484199] - Kuniba et al. [2009 - PMID: 19343044] reported a 1.27-Mb deletion spanning TRPM3, KLF9, SMC5 and MAMDC2 in a patient with Kabuki syndrome working diagnosis. Segregation studies were however not possible. At the time, the molecular etiology of Kabuki syndrome (KMT2D/KDM6A) was not known. ----- TRPM3 is not associated with any phenotype in OMIM or G2P. This gene is included in panels for ID offered by some diagnostic laboratories (eg. GeneDx participating in the above study). ----- As a result, TRPM3 seems to fulfill criteria for inclusion in the ID/epilepsy panels probably as green (# of individuals, degree of ID relevant, EEG-confirmed epilepsy) or amber (if further functional evidence would be required). [Please consider eligibility for inclusion in other possibly relevant panels eg. autism, etc]. Sources: Literature |
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Early onset or syndromic epilepsy v1.128 | TRPM3 |
Konstantinos Varvagiannis gene: TRPM3 was added gene: TRPM3 was added to Genetic epilepsy syndromes. Sources: Literature Mode of inheritance for gene: TRPM3 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown Publications for gene: TRPM3 were set to doi.org/10.1038/s41431-019-0462-x Phenotypes for gene: TRPM3 were set to Generalized hypotonia; Global developmental delay; Intellectual disability; Seizures; Autistic behavior Penetrance for gene: TRPM3 were set to unknown Mode of pathogenicity for gene: TRPM3 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: TRPM3 was set to GREEN Added comment: Dyment et al. (2019 - https://doi.org/10.1038/s41431-019-0462-x) report on 7 unrelated individuals with a recurrent de novo TRPM3 missense variant [NM_020952.4:c.2509G>A - NP_066003.3:p.(Val837Met)] as well as an additional individual with a further de novo missense variant [c.2810C>A or p.(Pro937Gln) - same ref. sequences]. Overlapping features included hypotonia (7/8 - in one case mixed tone abnormality), DD/ID (8/8 - all individuals at appropriate age - degree relevant), EEG-confirmed epilepsy (7/8). Autism-like features were observed in 4 (out of 6 for whom this information was reported). Other features were noted in a minority (or were private to certain) of these individuals. Different clinical types of seizures were reported incl. absence, generalized-toni-clonic, infantile spasms as well as subclinical ones. Onset was in infancy or early childhood. In all individuals the variant was found following trio exome sequencing. The first variant fulfilled ACMG criteria to be classified as pathogenic due to it's de novo occurrence, prevalence in affected individuals (>=6 affected individuals and in the same time) absence from population databases, in silico predictions in favour of pathogenicity (PS2, PS4_Moderate, PM2, PP3). The Pro937Gln variant is however classified as a VUS. The subject harboring this variant had an additional de novo variant in another gene (DDB1) not associated with any phenotype, to date. Several other genetic causes had previously been ruled out for most individuals by other investigations : aCGH was normal in all, FMR1 testing in 6 subjects, genes (PHF6, MECP2, MCT8) or smaller panels for ID (the latter in 3 subjects), mtDNA or testing of nuclear genes for mitochondrial disorders, etc. TRPM3 encodes transient receptor potential (TRP) cation channel, subfamily M, member 3. TRP channels are a superfamily of gated cation channels sensitive to various physical or chemical stimuli (Clapham 2003 - PMID: 14654832 cited) eg. temperature or pain. The gene is highly expressed in the brain in humans and other vertebrates (Grimm et al. 2003 - PMID : 12672799 and GTEx - https://gtexportal.org/home/gene/TRPM3). Animal models : In rat brain, expression is initially restricted to neurons but later - as myelination progresses - shifts to oligodendrocytes (cited : Hoffmann et al. 2010 - PMID: 20163522). Most subjects had normal brain MRI appart from one individual with nonspecific white matter hyperintensities and another with possible mild cerebral volume loss. Trpm3 -/- mice show attenuated nocifensive behavior after heat or dermal injection of pregnenolone sulfate. Heat or pain insensitivity was reported only for 2 individuals. Functional studies were not carried out, although some hypotheses are proposed following in silico modeling of the TRPM3 variants using an available structure for TRPM7. As discussed by Dyment et al., happloinsufficiency appears to be unlikely given the presence of LoF variants in ExAC/gnomAD (pLI of 0), some intragenic copy number variants in DGV. In addition, pathogenicity of deletions spanning only TRPM3 or additional proximal genes was not evident in 2 cases: - In the first case a exon 1-9 deletion was found in 2 brothers with Becker muscular dystrophy due to DMD intragenic duplication and autism/cognitive impairment though the TRPM3 deletion was found also in unaffected family members. The deletion was also found in unaffected relatives. A multiple hit hypothesis was hypothesized for this family. [Pagnamenta et al. 2011 - PMID: 21484199] - Kuniba et al. [2009 - PMID: 19343044] reported a 1.27-Mb deletion spanning TRPM3, KLF9, SMC5 and MAMDC2 in a patient with Kabuki syndrome working diagnosis. Segregation studies were however not possible. At the time, the molecular etiology of Kabuki syndrome (KMT2D/KDM6A) was not known. ----- TRPM3 is not associated with any phenotype in OMIM or G2P. This gene is included in panels for ID offered by some diagnostic laboratories (eg. GeneDx participating in the above study). ----- As a result, TRPM3 seems to fulfill criteria for inclusion in the ID/epilepsy panels probably as green (# of individuals, degree of ID relevant, EEG-confirmed epilepsy) or amber (if further functional evidence would be required). [Please consider eligibility for inclusion in other possibly relevant panels eg. autism, etc]. Sources: Literature |
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Early onset or syndromic epilepsy v1.85 | EFHC1 | Rebecca Foulger changed review comment from: PMID:28370826. Raju et al., 2017 examine 480 Juvenile myoclonic epilepsy patients from India, and identified 13 variants (11 of which were novel, 10 of which are predicted to be pathogenic) in 28 JME patients. They were absent or uncommon among controls. Patients with family histories of progressive myoclonic epilepsy (PME) were not included in the study. The authors submitted their variants to LOVD, including 14 polymorphisms that were common in controls and databases (https://databases.lovd.nl/shared/variants/EFHC1/unique).; to: PMID:28370826. Raju et al., 2017 examine 480 Juvenile myoclonic epilepsy patients from India, and identified 13 variants (11 of which were novel, 10 of which are predicted to be pathogenic) in 28 JME patients. They were absent or uncommon among controls. All variants were missense. Patients with family histories of progressive myoclonic epilepsy (PME) were not included in the study. The authors submitted their variants to LOVD, including 14 polymorphisms that were common in controls and databases (https://databases.lovd.nl/shared/variants/EFHC1/unique). | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v1.80 | CSNK2A1 |
Rebecca Foulger gene: CSNK2A1 was added gene: CSNK2A1 was added to Genetic epilepsy syndromes. Sources: Literature Mode of inheritance for gene: CSNK2A1 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown Publications for gene: CSNK2A1 were set to 30655572 Phenotypes for gene: CSNK2A1 were set to seizures; Okur-Chung neurodevelopmental syndrome, 617062; CSNK2A1 syndrome Review for gene: CSNK2A1 was set to AMBER Added comment: Added CSNK2A1 to the epilepsy panel based on PMID:30655572. Nakashima et al, 2019 describe 4 patients with DD and seizures. Two of the patients (both Japanese) had de novo variants in CSNK2A1: c.593A>G, p.Lys198Arg in Patient 1, c.571C>T, p.Arg191* in Patient 2. Although both shared global DD and seizures, patient 1 showed later onset (4 yrs old) seizures which were less frequent. Additional features in Patient 1 include facial dysmorphisms, short stature and muscle weakness. Patient 2 had a more severe phenotype with seizures starting in the early infantile stage (5 months) with acute encephalopathy and death age 1 yr, 7 months. Note that Patient 1 had 3 candidate de novo deleterious variants (ATAD2B, TOPORS, CSNK2A1): ACMG variant guidelines were used to evaluate the pathogenicity of the variants. ATAD2B and TOPORS variants were likely pathogenic, and CSNK2A1 variant was pathogenic. In Patient 2, no further likely de novo variants were found. Sources: Literature |
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Early onset or syndromic epilepsy v1.48 | NECAP1 | Rebecca Foulger commented on gene: NECAP1: PMID:30626896 (Mizuguchi et al. 2019) report a 16-month-old Malaysian boy who developed infantile-onset tonic-clonic and tonic seizures age 3 months, then spasms in clusters. WES identified the splice site variant c.301+1G>A in NECAP1. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v1.39 | ACTL6B | Rebecca Foulger commented on gene: ACTL6B: Bell et al., 2019 (PMID:31031012) identified 11 individuals (from 10 families) with biallelic variants in ACTL6B and global developmental delay, epileptic encephalopathy, and spasticity. Seizure types include myoclonias, tonic and myoclonic, focal onset progressing to infantile spasms, and Epilepsy was a feature of all 11 patients (Table 1). | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v1.39 | ACTL6B | Rebecca Foulger Added comment: Comment on mode of inheritance: Bell et al., 2019 (PMID:31031012) report biallelic and heterozygous variants in ACTL6B with ID/developmental delay. Seizures were reported in all the biallelic patients but infantile spasms and GTCS (generalized tonic-clonic seizure) was reported in only one heterozygous individual (D7). Therefore kept MOI as biallelic. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v1.14 | SLC35A3 | Rebecca Foulger commented on gene: SLC35A3: Marini et al. 2017 (PMID: 28328131) provide a second case. They report a non-consanguineous Italian family with two siblings manifesting severe EE. Both siblings exhibited infantile spasms associated with focal and tonic seizures from early infancy. In addition, both had quadriplegia, acquired microcephaly and severe ID. WGS identified novel compound het variants in SLC35A3 in both children. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v1.12 | GLRA1 | Louise Daugherty Phenotypes for gene: GLRA1 were changed from Hyperekplexia 1 149400 to Hyperekplexia, hereditary 1, 149400; Hyperekplexia; developmental delay; infantile spasms and generalized tonic-clonic seizures | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v1.6 | PPP2CA |
Konstantinos Varvagiannis gene: PPP2CA was added gene: PPP2CA was added to Genetic epilepsy syndromes. Sources: Literature Mode of inheritance for gene: PPP2CA was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown Publications for gene: PPP2CA were set to 29274472; 30030003 Phenotypes for gene: PPP2CA were set to Feeding difficulties; Muscular hypotonia; Global developmental delay; Intellectual disability; Language impairment; Seizures; Abnormality of nervous system morphology Penetrance for gene: PPP2CA were set to unknown Review for gene: PPP2CA was set to GREEN Added comment: Reynhout et al. (doi.org/10.1016/j.ajhg.2018.12.002 - PMID not available) report on 16 individuals with heterozygous pathogenic PPP2CA variants. Frequent features included feeding difficulties, hypotonia, developmental delay (16/16) with intellectual disability (probably 15/16 - a single individual developped cognitive dysfunction following a psychotic episode), language impairment, behavioral problems, seizures (10/16), brain abnormalities and variable other features. The variants reported included 3 nonsense mutations, 1 frameshift, 1 duplication of one amino acid, 9 missense variants (of which one was observed twice and 2 affected Asp223) as well as a partial gene deletion (spanning also CDKL3). Various mechanisms seemed to explain the effect of the different variants - among others - haploinsufficiency for some or a dominant negative effect for others, etc. Type 2A protein phosphatases (PP2As) comprise 3 subunits, a catalytic C-type subunit (PPP2CA encodes the Cα subunit), a scaffolding A-type subunit as well as a regulatory B-type subunit important for their function. Impairment of PP2A-B56δ (encoded by PPP2R5D) binding/functionality was suggested for most of the variants. Similar dysfunction has been observed - among others - upon loss of one functional allele of PPP2R1A. The effect of 2 variants affecting Asp223 (Asp223Val and Asp233His) was unclear as they largely behaved similar to wild-type in various functional assays. The authors argue that contribution of mutations in other genes could not be ruled out for the individuals harboring these variants, as could also be the case for the subject with disruption of (also) CDKL3. The authors note overlapping phenotype with PPP2R1A and PPP2R5D-related ID (MIM 616362 and 616355 respectively - genes rated green in this panel). Brain-specific Ppp2ca knockout in mice (PMID: 29274472) resulted in morphological and behavioral abnormalities partly overlapping with features observed in individuals with PPP2CA mutations. However mice heterozygous for null mutations have not been phenotypically examined (PMID: 30030003). --------- PPP2CA is not associated with any phenotype in OMIM, nor in G2P. --------- As a result, PPP2CA can be considered for inclusion in this panel as green (or amber). Sources: Literature |
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Early onset or syndromic epilepsy v1.6 | CTNNA2 |
Konstantinos Varvagiannis gene: CTNNA2 was added gene: CTNNA2 was added to Genetic epilepsy syndromes. Sources: Literature Mode of inheritance for gene: CTNNA2 was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: CTNNA2 were set to 30013181 Phenotypes for gene: CTNNA2 were set to Cortical dysplasia, complex, with other brain malformations 4, 618174 Penetrance for gene: CTNNA2 were set to Complete Review for gene: CTNNA2 was set to GREEN Added comment: Biallelic loss-of-function mutations in CTNNA2 cause cortical dysplasia, complex, with other brain malformations 9 (MIM 618174). ------- Schaffer et al. (PMID: 30013181) report on 7 individuals from 3 unrelated consanguineous families. All individuals presented with profoundly impaired motor and cognitive development (severe ID in 6/7 for whom this information was available, all 6 from 2 families - a further individual from the 3rd family was non-ambulatory with absent speech at the age of 28 months), with acquired microcephaly and intractable seizures (7/7 - onset: 6m-3y - atonic/myoclonic/infantile spasms). Pachygyria without posterior-anterior gradient or focal dysplasias was common to all. CTNNA2 encodes αN-catenin. It is expressed in human fetal brain, mainly in regions expressing migration markers DCX and TUJ1. Reduced migration was shown for iPSC-derived neural progenitor cells from an affected individual, compared to controls. The protein contains a putative actin-binding domain (ABD) at its C terminus. Several lines of evidence are provided that this domain is critical for the process of neuronal migration. ------- CTNNA2 is included in the DD panel of G2P associated with disordered cortical neuronal migration (Disease confidence: probable / ID and seizures among the phenotypes assigned to this entry). This gene is not commonly included in gene panels for intellectual disability. ------- As a result CTNNA2 could be considered for inclusion in this panel as green (or amber). Sources: Literature |
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Early onset or syndromic epilepsy v1.1 | FUK |
Konstantinos Varvagiannis gene: FUK was added gene: FUK was added to Genetic epilepsy syndromes. Sources: Literature Mode of inheritance for gene: FUK was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: FUK were set to 30503518 Phenotypes for gene: FUK were set to Feeding difficulties; Generalized hypotonia; Global developmental delay; Intellectual disability; Seizures; Abnormality of vision Penetrance for gene: FUK were set to Complete Review for gene: FUK was set to AMBER Added comment: Ng et al. (PMID: 30503518) report on 2 unrelated individuals with biallelic pathogenic variants in FUK. The common features consisted of feeding difficulties, hypotonia, global developmental delay with severe intellectual disability, seizures as well as visual impairment. The first patient was compound heterozygous for 2 missense variants (Ser223Pro and Arg683Cys) while the second - born to consanguineous parents - was homozygous for Lys994Gln. Significant reduction in the FUK protein amount was demonstrated upon Western blot for the first individual for whom fibroblast and lymphoblast cell lines were available. Fucokinase (FUK) is an enzyme of the fucose salvage pathway, one of the mechanisms (the other and main contributor being the de novo pathway) for synthesis of GDP-fucose. GDP-fucose is a donor substrate for fucosylation, a form of glycosylation. Significant decrease of fucokinase activity was shown for this individual when compared to controls. Cell lines from the second individual were not available for expression/functional studies. Overall the authors suggest that loss-of-function variants cause a congenital disorder of glycosylation with ID and seizures. There are no further cases published in the literature. FUK is not associated with any phenotype in OMIM nor in G2P. As a result this gene can be considered for inclusion in this panel as amber. [You might consider inclusion of this gene also in the CDG gene panel]. Sources: Literature |
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Early onset or syndromic epilepsy v0.1575 | KIF1A | Ellen McDonagh Added comment: Comment on publications: PMID: 25265257 - five cases of 14 reported with de novo KIF1A variants were epileptic or had epileptic abnormalities (infantile spasms, partial complex and myoclinic seizures). | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v0.1362 | CAD |
Konstantinos Varvagiannis gene: CAD was added gene: CAD was added to Genetic epilepsy syndromes. Sources: Literature Mode of inheritance for gene: CAD was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: CAD were set to 25678555; 28007989 Phenotypes for gene: CAD were set to Epileptic encephalopathy, early infantile, 50 - MIM 616457 Penetrance for gene: CAD were set to Complete Review for gene: CAD was set to GREEN Added comment: Biallelic pathogenic variants in CAD cause Epileptic encephalopathy, early infantile, 50 - MIM 616457. Overall 5 individuals from 4 unrelated families have been reported in detail in PMIDs 25678555 and 28007989 (table 1 in this article provides a summary). The phenotype consisted of developmental delay which preceded the onset of seizures (6 months to 2 years) and hematologic anomalies (anemia and anisopoikilocytosis). The patients presented developmental stagnation/regression, which in most cases occurred several months following the seizure onset. CAD is a tri-functional protein catalyzing the first 3 steps of the de novo pyrimidine biosynthesis. In total, 5 variants have been reported (2 missense, 1 nonsense and 2 splice-site SNVs) with functional studies (cDNA, metabolites) supporting pathogenicity and disruption of this pathway. CAD mutations have previously been studied in other model organisms. Mutations in enzymes catalyzing downstream steps of the same pathway are associated with other syndromes. The disorder appears to be amenable to dietary intervention (uridine supplementation). As a result, this gene can be considered for inclusion in the epilepsy panel as green (or amber). Sources: Literature |
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Early onset or syndromic epilepsy v0.1292 | EXOSC3 | Rebecca Foulger commented on gene: EXOSC3: Rudnik-Schoneborn et al 2013 (PMID:23284067) detected biallelic variants in EXOSC3 in 15 patients (10 of 27 families). Epileptic seizures occurred in 3 patients in 2 families, including absence epilepsy in patient 2-1 and infantile spasms in 2 sisters (5-1 and 5-2). | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v0.1060 | PHACTR1 |
Konstantinos Varvagiannis gene: PHACTR1 was added gene: PHACTR1 was added to Genetic epilepsy syndromes. Sources: Literature,Expert Review Mode of inheritance for gene: PHACTR1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted Publications for gene: PHACTR1 were set to 30256902; 23033978; 28135719 Phenotypes for gene: PHACTR1 were set to Global developmental delay; Intellectual disability; Seizures Penetrance for gene: PHACTR1 were set to unknown Review for gene: PHACTR1 was set to GREEN Added comment: PMID: 30256902 (Hamada et al., 2018) reports on the phenotype of 2 unrelated individuals with de novo missense variants in PHACTR1. Both had a diagnosis of West syndrome (infantile spasms and intellectual disability). As the authors note, 3 individuals with missense variants in this gene (in 2 of whom as a de novo occurrence) were previously identified : - In PMID: 23033978 (de Ligt et al., 2012) one patient with ID and epilepsy and a de novo missense variant. - In PMID: 28135719 (DDD study in 2017) one individual with developmental disorder and a further de novo missense SNV. - PMID: 27457812 (Riazuddin et al., 2017) is an exome sequencing study for intellectual disability. (NB. In the supplement of this study, the consanguineous parents of the affected individuals appear to be heterozygous for this variant but the affected children non-carriers). Extensive functional studies for the 2 novel as the 2 previously reported variants (from PMIDs: 23033978, 28135719) support a dominant negative effect for all 4 variants. One of these variants (reported by de Ligt al.) for which pathogenicity is suggested has however been reported 4 times in gnomAD. The authors discuss the possibility of reduced penetrance and/or other phenotypes in the individuals from gnomAD. Although all the variants studied appear to have a dominant negative effect, Phactr1-knockdown neurons seem to display aberrant migration and morphological phenotype. As a result, the eventual effect of haploinsufficiency probably needs to be further clarified. (Still PHACTR1 has a pLI score of 0.66 in ExAC). At least 3 individuals appeared to have epilepsy (as this information is not available for the DDD participant). As a result, this gene can be considered for inclusion in this panel as green (or amber). Sources: Literature, Expert Review |
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Early onset or syndromic epilepsy v0.977 | D2HGDH | Rebecca Foulger commented on gene: D2HGDH: Struys et al 2005 (PMID:15609246) report two unrelated patients affected with severe D-2-hydroxyglutaric aciduria and disease-causing variants in D2HGDH. Patient one suffered tonic, tonic-clonic, and myoclonic seizures, and was homozygous for missense variant in D2HGDH (c.1331T-->C; p.Val444Ala). Patient 2 presented with generalized tonic-clonic seizures and infantile spasms amongst her symptoms. She was compound heterozygous for a missense mutation (c.440T-->G; p.Ile147Ser) and a splice-site mutation (IVS1-23A-->G) that resulted in a null allele. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v0.847 | FH | Louise Daugherty edited their review of gene: FH: Added comment: From GeneReview PMID: 20301679. Fumarate hydratase deficiency results in severe neonatal and early infantile encephalopathy that is characterized by poor feeding, failure to thrive, hypotonia, lethargy, and seizures. Epileptic seizures are common (40%-80%), although age of onset and seizure type are variable (PMID:10805328, PMID:20549362). Infantile spasms (epileptic spasms) accompanied by hypsarrhythmia on EEG have been reported (PMID:15221078, PMID:16151915).; Changed rating: GREEN | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v0.811 | SUCLA2 | Rebecca Foulger commented on gene: SUCLA2: PMID:26475597 (Carrozzo et al 2016) report 25 new patients with succinate-CoA ligase deficiency, and review the clinical and molecular findings in these and 46 previously reported patients. Of the 71 patients, 50 had SUCLA2 mutations and 21 had SUCLG1 mutations. Epilepsy reported as generalized seizures, unspecified epilesy or infantile spasms was mainly reported in patients with SUCLA2 variants. Only 1 patient with the SUCLG1 variant had epilepsy (5%). At least 3 cases of epilepsy listed in new patients with SUCLA2 variants (supplementary material). | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v0.785 | COL4A1 | Sarah Leigh Phenotypes for gene: COL4A1 were changed from to Angiopathy, hereditary, with nephropathy, aneurysms, and muscle cramps 611773; Brain small vessel disease with or without ocular anomalies 607595; Porencephaly 1 175780; Schizencephaly 269160 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v0.690 | SMS | Sarah Leigh Marked gene: SMS as ready | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v0.690 | SMS | Sarah Leigh Added comment: Comment when marking as ready: Associated with relevant phenotype in OMIM and as probable Gen2Phen gene. At least 3 variants reported in unrelated cases of Mental retardation, X-linked, Snyder-Robinson type 309583 manifesting seizures. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v0.690 | SMS | Sarah Leigh Gene: sms has been classified as Green List (High Evidence). | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v0.690 | SMS | Sarah Leigh Classified gene: SMS as Green List (high evidence) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v0.690 | SMS | Sarah Leigh Gene: sms has been classified as Green List (High Evidence). | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v0.689 | SMS | Sarah Leigh Publications for gene: SMS were set to | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v0.688 | SMS | Sarah Leigh Phenotypes for gene: SMS were changed from to Mental retardation, X-linked, Snyder-Robinson type 309583 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v0.686 | SMS | Sarah Leigh Mode of inheritance for gene: SMS was changed from to X-LINKED: hemizygous mutation in males, biallelic mutations in females | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v0.647 | TBL1XR1 | Rebecca Foulger commented on gene: TBL1XR1: In a 5-year-old Japanese girl with autosomal dominant mental retardation-41 (MRD41; 616944), Saitsu et al. (2014, PMID:25102098) identified a de novo heterozygous transition (c.209G-A, NM_024665.4) in the TBL1XR1 gene (G70D). The patient developed infantile spasms at age 5 months. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v0.585 | MAGI2 | Sarah Leigh Phenotypes for gene: MAGI2 were changed from Infantile Spasms to Nephrotic syndrome, type 15 617609; Infantile Spasms | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v0.486 | MAGI2 | Sarah Leigh Phenotypes for gene: MAGI2 were changed from Infantile Spasms to Infantile Spasms | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v0.432 | TUBA8 | Rebecca Foulger commented on gene: TUBA8: 4 patients with 'Cortical dysplasia, complex, with other brain malformations 8, MIM:613180' were reported by Abdollahi et al. (2009, PMID:19896110). The 4 children come from 2 unrelated consanguineous Pakistani families, and all 4 children presented with seizures (infantile spasms or Tonic clonic). | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy v0.410 | ISCA-37430-Loss |
Louise Daugherty Region: ISCA-37430-Loss was added Region: ISCA-37430-Loss was added to Genetic Epilepsy Syndromes. Sources: ClinGen,Expert Review Green Mode of inheritance for Region: ISCA-37430-Loss was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown Publications for Region: ISCA-37430-Loss were set to 19584063; 1671808; 1879837; 3391613; 12621583; 7634541 Phenotypes for Region: ISCA-37430-Loss were set to microcephaly, dysgenesis of the corpus callosum, and cerebellar atrophy, as well as neurobehavioral disorders, including delayed development, mental retardation, and attention deficit-hyperactivity disorder. Patients with duplications of YWHAE tended to have macrosomia, facial dysmorphism, and mild developmental delay; growth restriction, craniofacial dysmorphisms, structural abnormalities of brain and cognitive impairment; Chromosome 17p13.3 duplication syndrome; prominent forehead, bitemporal hollowing, short nose with upturned nares, protuberant upper lip, thin vermilion border, and small jaw; Characteristic facies, pre- and post-natal growth retardation; 247200; classic lissencephaly (pachygyria, incomplete or absent gyration of the cerebrum), microcephaly, wrinkled skin over the glabella and frontal suture, prominent occiput, narrow forehead, downward slanting palpebral fissures, small nose and chin, cardiac malformations, hypoplastic male extrenal genitalia, growth retardation, and mental deficiency with seizures and EEG abnormalities; Miller-Dieker lissencephaly syndrome |
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Early onset or syndromic epilepsy v0.410 | ISCA-37411-Loss |
Louise Daugherty Region: ISCA-37411-Loss was added Region: ISCA-37411-Loss was added to Genetic Epilepsy Syndromes. Sources: ClinGen,Expert Review Green Mode of inheritance for Region: ISCA-37411-Loss was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown Publications for Region: ISCA-37411-Loss were set to 19289393; 19136953; 18278044 Phenotypes for Region: ISCA-37411-Loss were set to PMID: 19289393 incomplete penetrance for developmental delay, mental retardation, or borderline IQ in most and autistic spectrum disorder (6/14), speech delay, aggressiveness, attention deficit hyperactivity disorder, and other behavioural problems; 612001; PMID: 18278044 mental retardation, epilepsy and variable facial and digital dysmorphisms; PMID: 19136953 idiopathic generalized epilepsy without other features previously associated with 15q13.3 microdeletions, such as intellectual disability, autism or schizophrenia |
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Early onset or syndromic epilepsy v0.410 | ISCA-37478-Gain |
Louise Daugherty Region: ISCA-37478-Gain was added Region: ISCA-37478-Gain was added to Genetic Epilepsy Syndromes. Sources: ClinGen,Expert Review Green Mode of inheritance for Region: ISCA-37478-Gain was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown Publications for Region: ISCA-37478-Gain were set to 18374305; 16840569; 9106540 Phenotypes for Region: ISCA-37478-Gain were set to hypotonia and motor delays, intellectual disability, autism spectrum disorder (ASD), and epilepsy including infantile spasms, 608636; chromosome 15q11-q13 duplication syndrome; autism, mental retardation, ataxia, seizures, developmental delays, and behavioral problems |
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Early onset or syndromic epilepsy | SMS | Zornitza Stark reviewed gene: SMS | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Early onset or syndromic epilepsy | SMS | Sarah Leigh Added gene to panel |