Gene therapy for monogenic auditory neuropathy (AN) has successfully improved hearing function in target gene -deficient mice. Accurate genetic diagnosis can not only clarify the etiology but also accurately locate the lesion site, providing a basis for gene therapy and guiding patient intervention and management strategies. In this study, we collected data from a family with a pair of sisters with prelingual deafness. According to their auditory tests, subject II -1 was diagnosed with profound sensorineural hearing loss (SNHL), II -2 was diagnosed with AN, I-1 was diagnosed with highfrequency SNHL, and I-2 had normal hearing. Using whole-exome sequencing (WES), one nonsense mutation, c.4030C>T (p.R1344X), and one missense mutation, c.5000C>A (p.A1667D), in the OTOF (NM_001287489.1) gene were identified in the two siblings. Their parents were heterozygous carriers of c.5000C>A (father) and c.4030C>T (mother). We hypothesized that c.5000C>A is a novel pathogenic mutation. Thus, subject II -1 should also be diagnosed with AN caused by OTOF mutations. These findings not only expand the OTOF gene mutation spectrum for AN but also indicate that WES is an effective approach for accurately diagnosing AN.