Deafness_IsolatedAndComplex
Gene: SLC9A1
ClinGen classification: Moderate
SLC9A1 was first reported in relation to autosomal recessive Lichtenstein-Knorr syndrome in 2015 (Guissart et al, PMID: 25205112). Evidence supporting this gene-disease relationship includes case-level data, segregation data, and experimental data.
Four variants (missense, nonsense, frameshift) that have been reported in four probands in four publications (PMIDs: 25205112, 30018422, 30237576, 36561016) are included in this curation. Patients with recessive SLC9A1 variants have mainly been reported to exhibit early-onset cerebellar ataxia, seizures, cerebral atrophy and variable hearing loss (PMID: 25205112, 30018422, 36561016). Recently Pellerin, Ceravolo, and colleagues reported individuals from consanguineous families carrying recessive SLC9A1 variants presenting with amelogenesis imperfecta in addition to early-onset cerebellar ataxia associated with cerebellar atrophy, developmental delay, and variable sensorineural hearing loss (Journal of the Neurological Sciences, Volume 455, 121930).
This gene-disease relationship is supported by animal model and expression studies. SLC9A1 is shown to be ubiquitously expressed in various tissues throughout the body (PMID: 23715323, dbGaP Accession phs000424.v10.p2). Homozygous SLC9A1 null mutant mice models showed reduced postnatal growth, ataxia, and epileptic-like seizures without cerebellar atrophy (PMID: 10199808).
In summary, there is moderate evidence to support this gene-disease relationship. While more evidence is needed to establish this relationship definitively, no convincing contradictory evidence has emerged. This classification was approved by the ClinGen Cerebellar Ataxia GCEP on the meeting date July 9th, 2025 (SOP Version 11).Created: 14 Aug 2025, 11:22 p.m. | Last Modified: 14 Aug 2025, 11:22 p.m.
Panel Version: 1.216
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
Lichtenstein-Knorr syndrome MONDO:0014572
Two families with bi-allelic variants in this gene reported and combination of deafness and ataxia.
Sources: Expert listCreated: 17 Apr 2020, 12:47 a.m.
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
Lichtenstein-Knorr syndrome, MIM# 616291
Publications
Gene: slc9a1 has been classified as Green List (High Evidence).
Gene: slc9a1 has been classified as Amber List (Moderate Evidence).
Gene: slc9a1 has been classified as Amber List (Moderate Evidence).
gene: SLC9A1 was added gene: SLC9A1 was added to Deafness. Sources: Expert list Mode of inheritance for gene: SLC9A1 was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: SLC9A1 were set to 25205112; 30018422; 25760855 Phenotypes for gene: SLC9A1 were set to Lichtenstein-Knorr syndrome, MIM# 616291 Review for gene: SLC9A1 was set to AMBER