OTOA encodes otoancorin, a glycosylphosphatidylinositol (GPI)-anchored protein essential for inner ear development and hearing function 1. The protein is required for proper development of the tectorial membrane in the inner ear and may function as an adhesion molecule 1. Experimental studies confirm that OTOA is GPI-anchored to cell surfaces, with sequences downstream from amino acid 589 being critical for proper GPI anchorage 1. Mutations in OTOA cause autosomal recessive nonsyndromic hearing loss (DFNB22), which exhibits a characteristic mid-frequency hearing loss pattern 2. The hearing loss associated with OTOA mutations is progressive, with losses exceeding 10 dB per decade 3. OTOA variants are found with significant frequency in populations, with allelic frequencies of 0.61-0.69% reported in Brazilian and other cohorts 4. Both single nucleotide variants and copy number variations (deletions) in OTOA cause hearing loss, with CNVs representing the second most frequent cause among identified variants in Japanese hearing loss patients 2. The gene accounts for a notable proportion of autosomal recessive hearing loss cases, with diagnostic yields ranging from 0.3% in Japanese populations to higher frequencies in other ethnic groups 25.