ClinVar Genomic variation as it relates to human health

The c.3902G>T variant in USH2A is a missense variant predicted to cause substitution of glycine by valine at amino acid 1301 (p.Gly1301Val). The highest population filtering allele frequency with a confidence interval of 0.95 in gnomAD v4.0.0 is 0.5% (469/91078) with 4 homozygotes in the South Asian population, which meets the ClinGen Hearing Loss VCEP criteria for BA1 (>=0.5%). The computational predictor REVEL gives a score of 0.218, which is neither above nor below the thresholds predicting a damaging or benign impact on USH2A function. While this variant has been reported in several individuals with clinical features of USH2A-related disorders, there are no case-control studies and several affected individuals had an alternate cause of disease identified (PMID:21569298, 25649381, 26927203, 32531858). In summary, this variant meets the criteria to be classified as benign, based on the ACMG/AMP criteria applied, as specified by the ClinGen Hearing Loss VCEP (BA1, ClinGen Hearing Loss VCEP specifications version 2, 03.20.2024).

See Variant Classification Assertion Criteria.

The USH2A c.3902G>T; p.Gly1301Val variant (rs111033524) is reported in the medical literature in individuals with Usher syndrome and retinitis pigmentosa, however, one of these individuals also carried an alternate molecular explanation for disease (Bonnet 2011, Pierrache 2016). The variant is reported with discrepant classifications in the ClinVar database (Variation ID: 48509) and in the Genome Aggregation Database in 0.6% (184/30778 alleles) of the South Asian population. The glycine at this codon is moderately conserved but computational analyses (SIFT:Tolerated, PolyPhen-2: Probably Damaging) predict conflicting effects of this variant on protein structure/function. Although there is information indicating this variant may not be pathogenic, there is insufficient evidence to classify the variant with certainty. Pathogenic USH2A variants are causative for autosomal recessive Usher syndrome (MIM: 276901) and retintitis pigmentosa (MIM: 613809). References: Bonnet C et al. Complete exon sequencing of all known Usher syndrome genes greatly improves molecular diagnosis. Orphanet J Rare Dis. 2011 May 11;6:21. Pierrache LH et al. Visual Prognosis in USH2A-Associated Retinitis Pigmentosa Is Worse for Patients with Usher Syndrome Type IIa Than for Those with Nonsyndromic Retinitis Pigmentosa. Ophthalmology. 2016 May;123(5):1151-60.

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. However, the evidence from the literature, in combination with allele frequency data from public databases where available, was not sufficient to rule this variant in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance.

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance.

The USH2A c.3902G>T variant was identified in an individual with retinitis pigmentosa with a presumed recessive inheritance pattern. Through a review of available evidence we were able to apply the following criteria: BP5, BA1, PP3. Based on this evidence we have classified this variant as Benign.

USH2A: BP4

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications).