| Date | Panel | Item | Activity | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Ataxia and cerebellar anomalies - narrow panel v4.38 | SLC25A46 | Achchuthan Shanmugasundram Tag Q4_22_promote_green was removed from gene: SLC25A46. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Ataxia and cerebellar anomalies - narrow panel v4.37 | SLC25A46 | Eleanor Williams reviewed gene: SLC25A46: Rating: GREEN; Mode of pathogenicity: ; Publications: ; Phenotypes: ; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Ataxia and cerebellar anomalies - narrow panel v4.35 | SLC25A46 |
Achchuthan Shanmugasundram Source Expert Review Green was added to SLC25A46. Source NHS GMS was added to SLC25A46. Rating Changed from Amber List (moderate evidence) to Green List (high evidence) |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Ataxia and cerebellar anomalies - narrow panel v3.11 | SLC25A46 |
Achchuthan Shanmugasundram changed review comment from: Comment on classification of this gene: The rating for this gene should be GREEN, as this gene has been implicated in ataxia, as identified from biallelic loss-of-function variants from at least 8 unrelated individuals/ families from multiple ethnicities and supported by results from animal models. Two brothers of consanguineous parents of Pakistani origin were identified with homozygous variant in SLC25A46 (c.413T>G./ p.Leu138Arg). The younger of the two brothers was presented with balancing difficulties in infancy, prominent myoclonus, cerebellar ataxia, profound visual loss, rod cone dysfunction, exotropia, difficulty initiating saccades, mild spasticity, and axonal sensory-motor neuropathy leading to trophic changes. He also developed scoliosis and had cerebellar atrophy as well as T2/FLAIR (fluid-attenuated inversion recovery) hyperintensities and cavitations in the cerebellum. The older brother was mildly affected with similar clinical manifestations (PMID:27430653). A study on patients from three North African families (Two siblings from Tunisian family and two unrelated Algerians) showed that the previously reported variant c.1018C>T/ p.Arg340Cys (displayed in Tunisian siblings and one Algerian patient) was associated with childhood onset, optic atrophy, gait and speech difficulties and wasting of the lower limbs, and the Algerian patient with the novel variant p.Trp160Ser did not present with optic atrophy, while all patients were presented with ataxia (PMID:28558379). Similarly, ataxia was also observed in Sardinian (p.Arg340Cys) and Palestinian (c.1005A>T/ p.Glu335Asp) patients from Abrams et al, 2015 (PMID:26168012). A six year old boy with homozygous missense variant c.770G>A (p.Arg257Gln) was reported with optic atrophy, peripheral neuropathy, ataxia, but not cerebellar atrophy (PMID:30178502). p.Arg340Cys variant was also identified in the eleven year old male patient and in other unaffected family members, and the patient was presented with insidious onset, progressive vision loss and swaying since 8 years of age. The other presentations were gait ataxia, torticollis to left and tilt to right, head tremors and myoclonus (PMID:33816684). Mouse models with loss-of-function mutation or lacking SLC25A46 gene manifest the main clinical features identified in patients such as ataxia, optic atrophy, cerebellar hypoplasia and peripheral neuropathy which were completely rescued by expression of human ortholog (PMID:28376086; PMID:28934388). The results suggest that the gene loss causes degeneration in neurons by affecting mitochondrial dynamics and energy production. Loss-of-function in cultured cells and in zebrafish also led to increased mitochondrial connectivity, while severely affecting the development and maintenance of neurons in the zebrafish (PMID:26168012). SLC25A46 has been associated with neuropathy, hereditary motor and sensory, type VIB in OMIM and Gene2Phenotype and with pontocerebellar hypoplasia, type 1E in OMIM.; to: Comment on classification of this gene: The rating for this gene should be GREEN, as this gene has been identified to be implicated in cerebellar ataxia (MONDO:0000437) from biallelic loss-of-function variants from at least 8 unrelated individuals/ families and in pontocerebellar hypoplasia, type 1E (MIM# 619303) from biallelic loss-of-function variants from at least 6 unrelated individuals/ families. These cases were from multiple ethnicities and were supported by results from animal models. In addition, this gene has also been identified to be implicated in cerebellar hypoplasia from monoallelic loss-of-function variants from a family of three siblings. As we currently do not have three unrelated cases for monoallelic inheritance, this gene is assigned only to biallelic MOI. Cerebellar ataxia: Two brothers of consanguineous parents of Pakistani origin were identified with homozygous variant in SLC25A46 (c.413T>G./ p.Leu138Arg). The younger of the two brothers was presented with balancing difficulties in infancy, prominent myoclonus, cerebellar ataxia, profound visual loss, rod cone dysfunction, exotropia, difficulty initiating saccades, mild spasticity, and axonal sensory-motor neuropathy leading to trophic changes. He also developed scoliosis and had cerebellar atrophy as well as T2/FLAIR (fluid-attenuated inversion recovery) hyperintensities and cavitations in the cerebellum. The older brother was mildly affected with similar clinical manifestations (PMID:27430653). A study on patients from three North African families (Two siblings from Tunisian family and two unrelated Algerians) showed that the previously reported variant c.1018C>T/ p.Arg340Cys (displayed in Tunisian siblings and one Algerian patient) was associated with childhood onset, optic atrophy, gait and speech difficulties and wasting of the lower limbs, and the Algerian patient with the novel variant p.Trp160Ser did not present with optic atrophy, while all patients were presented with ataxia (PMID:28558379). Similarly, ataxia was also observed in Sardinian (p.Arg340Cys) and Palestinian (c.1005A>T/ p.Glu335Asp) patients from Abrams et al, 2015 (PMID:26168012). A six year old boy with homozygous missense variant c.770G>A (p.Arg257Gln) was reported with optic atrophy, peripheral neuropathy, ataxia, but not cerebellar atrophy (PMID:30178502). p.Arg340Cys variant was also identified in the eleven year old male patient and in other unaffected family members, and the patient was presented with insidious onset, progressive vision loss and swaying since 8 years of age. The other presentations were gait ataxia, torticollis to left and tilt to right, head tremors and myoclonus (PMID:33816684). Cerebellar hypoplasia: Four infants from two different families with homozygous variants (family 1: c.1022T>C/ p.Leu341Pro; family 2: deletion of exon 1) were reported to have died soon after birth with a profound neurodevelopmental disorder associated with congenital pontocerebellar hypoplasia (PMID:27543974). The phenotypes are similar to a female infant from the United States with pontocerebellar atrophy who died at age 15 weeks. This infant reported by Abram et al (2015) exhibited compound heterozygous variants (c.882_885dupTTAC/ p.Asn296fs*297 & c.998C>T/ p.Pro333Leu) (PMID:26168012). Four infants from two unrelated families of German and Italian descent were reported with PCH1E. All died in the first days or weeks of life. The German infants were identified with homozygous variant c.736A>T (p.Arg246Ter) and the Italian infants were identified with compound heterozygous variants c.42C>G (p.Tyr14Ter) & 462+ 1G>A (PMID:28653766). Two siblings with bi-allelic compound heterozygous variants (a splicing variant - c.385-1G > A and a deletion) had a fulminant neonatal course. The mother of these siblings exhibited a heterozygous c.385-1G > A allele and the father had an 80-kb deletion spanning SLC25A46 and TMEM232 genes. Pontocerebellar hypoplasia was reported by postmortem brain CT imaging in one of the siblings (PMID:35012485). Barth (1993) reported a Dutch family in which three siblings died within the first day of life due to lack of spontaneous respiration and profound muscle weakness (PMID:8147499). Although these infants displayed similarities to the clinical indications described by Wan et al, 2016 (PMID:27543974), they were identified to possess heterozygous variant leading to a premature stop codon (c.691C>T/ p.Arg231Ter) in exon 8 of the SLC25A46 gene (PMID:28637197). Functional studies: Mouse models with loss-of-function mutation or lacking SLC25A46 gene manifest the main clinical features identified in patients such as ataxia, optic atrophy, cerebellar hypoplasia and peripheral neuropathy which were completely rescued by expression of human ortholog (PMID:28376086; PMID:28934388). The results suggest that the gene loss causes degeneration in neurons by affecting mitochondrial dynamics and energy production. Loss-of-function in cultured cells and in zebrafish also led to increased mitochondrial connectivity, while severely affecting the development and maintenance of neurons in the zebrafish (PMID:26168012). SLC25A46 has been associated with neuropathy, hereditary motor and sensory, type VIB in OMIM and Gene2Phenotype and with pontocerebellar hypoplasia, type 1E in OMIM. |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Ataxia and cerebellar anomalies - narrow panel v3.11 | SLC25A46 | Achchuthan Shanmugasundram Tag Q4_22_promote_green tag was added to gene: SLC25A46. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Ataxia and cerebellar anomalies - narrow panel v3.11 | SLC25A46 | Achchuthan Shanmugasundram Phenotypes for gene: SLC25A46 were changed from Neuropathy, hereditary motor and sensory, type VIB, MIM# 616505 to Cerebellar ataxia, MONDO:0000437; Pontocerebellar hypoplasia, type 1E, MIM# 619303, MONDO:0030260; Neuropathy, hereditary motor and sensory, type VIB, MIM# 616505 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Ataxia and cerebellar anomalies - narrow panel v3.10 | SLC25A46 | Achchuthan Shanmugasundram Classified gene: SLC25A46 as Amber List (moderate evidence) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Ataxia and cerebellar anomalies - narrow panel v3.10 | SLC25A46 | Achchuthan Shanmugasundram Gene: slc25a46 has been classified as Amber List (Moderate Evidence). | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Ataxia and cerebellar anomalies - narrow panel v3.9 | SLC25A46 | Achchuthan Shanmugasundram reviewed gene: SLC25A46: Rating: GREEN; Mode of pathogenicity: None; Publications: 26168012, 27430653, 28376086, 28558379, 28934388, 30178502, 33816684; Phenotypes: Cerebellar ataxia, MONDO:0000437, Pontocerebellar hypoplasia, type 1E, MIM# 619303, MONDO:0030260, Neuropathy, hereditary motor and sensory, type VIB, MIM# 616505; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Ataxia and cerebellar anomalies - narrow panel v2.12 | SLC25A46 |
Zornitza Stark gene: SLC25A46 was added gene: SLC25A46 was added to Ataxia and cerebellar anomalies - narrow panel. Sources: Expert list Mode of inheritance for gene: SLC25A46 was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: SLC25A46 were set to 30178502; 26168012; 27543974; 27430653; 27390132; 28934388; 28558379 Phenotypes for gene: SLC25A46 were set to Neuropathy, hereditary motor and sensory, type VIB, MIM# 616505 Review for gene: SLC25A46 was set to GREEN gene: SLC25A46 was marked as current diagnostic Added comment: Hereditary motor and sensory neuropathy type VIB is an autosomal recessive complex progressive neurologic disorder characterized mainly by early-onset optic atrophy resulting in progressive visual loss and peripheral axonal sensorimotor neuropathy with highly variable age at onset and severity. Affected individuals also have cerebellar or pontocerebellar atrophy on brain imaging, and they show abnormal movements, such as ataxia, dysmetria, and myoclonus. At least 10 unrelated families reported, supportive functional data. Sources: Expert list |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||