Simultaneous MT-RNR1 and MYO15A Mutations in a Family with Non-Syndromic Hearing Loss

Congenital hearing loss is one of the prevalent birth defects, with approximately 60% of cases attributed to genetic factors. Genetic hearing lossis broadly classified into syndromic and non-syndromic forms, with non-syndromic hearing loss accounting for 70% of cases. MYO15A mutationsare known to cause autosomal recessive non-syndromic hearing loss (ARNSHL), while MT-RNR1 mutations follow a maternal inheritance patternand are linked to aminoglycoside-induced hearing loss. In this study, a family with diverse manifestations of non-syndromic hearing loss wasinvestigated, including aminoglycoside-induced, congenital profound, and post-lingual profound hearing loss. Through whole exome sequencing, distinct genetic etiologies responsible for hearing loss in affected family members were identified. This is the first report to document theco-occurrence of a compound heterozygous MYO15A mutation alongside an MT-RNR1 mutation within a pedigree. Additionally, it is the first observation of both a homozygous MYO15A c.6956+9C>G mutation and compound heterozygous MYO15A mutations (c.[6956+9C>G]+[4898T>C]) inARNSHL. These findings broaden the genotype-phenotype spectrum of MYO15A and highlight the critical role of genetic diagnosis in managinghearing loss.