Clinical characterization of a novel COCH mutation G87V in a Chinese DFNA9 family

ObjectivesTo characterize the clinical features of a Chinese DFNA9 family associated with a novel COCH mutation and to confirm the proposed genotype–phenotype correlation of COCH.MethodsMutation screening of 79 deafness genes was performed in the proband by targeted next-generation sequencing. Co-segregation of the disease phenotype and the detected variants was confirmed in all family members by PCR amplification and Sanger sequencing. The progression of hearing impairment in affected family members was followed and the concomitant vestibular dysfunction was verified by the caloric vestibulo-ocular reflex test.ResultsA novel COCH mutation p.G87V was identified in the family segregating with late-onset, progressive sensorineural hearing impairment and consistent vestibular dysfunction.ConclusionThe p.G87V mutation leads to a very similar phenotype as a previously reported p.G87W mutation of COCH. Our study suggested that the G87 residue is critical for function of COCH and further confirms a previously proposed genotype–phenotype correlation for DFNA9.