Hearing and Vestibular Impairment Related to a Variant (c.263G>C) of the COCH Gene

Abstract Objective To ascertain pathogenic variants frequency and type in the COCH gene among Cantabrian patients with nonsyndromic hereditary hearing loss (HL), and to understand their cochleovestibular manifestations. Study Design An observational study on patients with postlingual nonsyndromic sensorineural hearing loss (SNHL), who underwent a genetic study using next‐generation sequencing (gene panel) in the otolaryngology clinics between January 2019 and December 2023. Setting Referral center Marqués de Valdecilla University Hospital in Santander (Spain). Methods A cohort of 248 otolaryngologic clinic‐referred patients suspected of genetic SNHL underwent sequencing analysis targeting 231 genes. Results A likely pathogenic or pathogenic variant causing HL was found in 57 (22.8%) patients. Among them, 7 (2.8%) were heterozygous carriers of the c.263G>C variant in the LCCL domain of the COCH gene, included as index cases. Subsequent familial segregation studies were performed. A total of 22 genetically and clinically studied patients were included. All but 3 family members displayed bilateral progressive SNHL starting in adulthood. Thirteen patients reported instability, but none met Meniere's disease criteria. Conclusion COCH gene variants are frequent in Cantabria. A variant with pathogenic evidence (c.263G>C in the LCCL domain) was detected. The phenotype observed is similar to a subgroup of patients with other variants described in the same functional domain: progressive SNHL and instability secondary to vestibular hypofunction.