Identifying DNA Variants in a Turkish Cohort with Inner Ear Anomalies

To determine the genetic causes of sensorineural hearing loss (SNHL) associated with inner ear anomalies, 11 unrelated Turkish individuals diagnosed with SNHL and an inner ear anomaly using temporal bone computed tomography and inner ear magnetic resonance imaging underwent exome or whole genome sequencing to identify underlying genetic defects. None of the individuals was diagnosed with a recognized syndrome. Four of the 11 probands were homozygous for SLC26A4 variants, c.283G>A, c.845G>A, c.1061T>C, and c.1198delT. Another proband was homozygous for a TECTA variant, c.4163G>A. Patients with variants of the SLC26A4 gene had bilateral enlarged vestibular aqueduct, bilateral incomplete partition type 2 anomaly, bilateral hypoplastic cochlea and bilateral enlarged vestibular aqueduct plus hypoplastic cochlea anomaly. Patients with the variant TECTA gene had bilateral hypoplastic cochlea. This study identified variants of SLC26A4 in 36% of probands with inner ear anomalies. While we identified a variant of the TECTA gene in a proband with cochlear hypoplasia, further studies are needed to see if TECTA variants can cause cochlear malformations.