MYO7A p.Arg1873Gln

The allele frequency of the p.Arg1873Gln variant in the MYO7A gene is 0.008% (2/24854) of European chromosomes by gnomAD, which is a low enough frequency to apply PM2_Supporting based on the thresholds defined by the ClinGen Hearing Loss Expert Panel for autosomal recessive hearing loss (PM2_Supporting). This variant has been detected in 2 probands with hearing loss and 2 probands with Usher syndrome. For 2 of those probands, a pathogenic or suspected-pathogenic variant was observed in trans, for 1 proband a pathogenic or suspected-pathogenic was suspected in trans, and for 1 of the probands, a rare variant of uncertain significance was observed in trans (PM3_Strong; PMID:23208854, 28000701, 29196752, Partners LMM internal data SCV000059849.6). The variant has been reported to segregate with hearing loss in one affected family member (PP1, Partners LMM internal data SCV000059849.6). A different pathogenic missense variant (p.Arg1873Trp) has been previously identified at this codon of MYO7A which may indicate that this residue is critical to the function of the protein (PM5; p.Arg1873Trp ClinVar Variation ID 43291). The REVEL computational prediction analysis tool produced a score of 0.936, which is above the threshold necessary to apply PP3. At least one of the above patients with the variant in this gene displayed features of Usher syndrome (PP4; Partners LMM internal data SCV000059849.6). In summary, this variant meets criteria to be classified as pathogenic for autosomal recessive Usher syndrome based on the ACMG/AMP criteria applied, as specified by the Hearing Loss Expert Panel: PM3_Strong, PM2_Supporting, PM5, PP1, PP3, PP4.