Detection of Two Pathogenesis Previously Unreported Myosin XVa Pathogenic Variants in Two Large Iranian Pedigrees with Autosomal Recessive Nonsyndromic Hearing Loss

Purpose: Hearing loss (HL) is a genetically heterogeneous common neurosensory disorder. Among different ethnic groups, pathogenic variants of Myosin XVa ( MYO15A ) at the DFNB3 locus are the common causes of autosomal recessive nonsyndromic hearing loss (ARNSHL). The aim of this study was to determine the prevalence and the type of MYO15A pathogenic variants in a subset of Iranian pedigrees with ARNSHL. Materials and Methods: Thirty-eight Iranian pedigrees with no Gap junction beta-2 pathogenic variants were included in the study. For all pedigrees, linkage analysis was performed using five short tandem repeat markers of DFNB3 locus. The DNA sequencing was then applied to identify MYO15A pathogenic variants in linked pedigrees. Results: Altogether, two out of 38 (5.3%) pedigrees were linked to locus 3. After sequencing, five previously unreported MYO15A pathogenic variants (c.1775-1776insA, c.1766-1767insC, c.7694delA, c.611G > C (G204A), and c.6442T > A (W2148R)) were revealed in homozygous and heterozygous state in the two pedigrees studied. Furthermore, the pathogenicity of pathogenic variants was confirmated by Insilco and cosegregation analysis in this study. Conclusions: Our findings support a relatively high prevalence and specificity of MYO15A pathogenic variant among Iranian ARNSHL patients. Molecular study of MYO15A may lead to elucidation of the population-specific pathogenic variant profile, which is of importance in molecular diagnostics of HL.