Temporal bone histopathology in dominantly inherited audiovestibular syndrome

Objective: To describe the clinical and pathologic features of a new dominantly inherited audiovestibular syndrome. Methods: History, examination, and audiometric testing in the proband, brother, and son; quantitative rotational testing in the proband and son; histopathology of the cochlea and vestibular labyrinth in the proband; sequencing candidate genes COCH and MYO7A in the brother and son. Results: Affected family members developed slowly progressive hearing loss beginning in their late 30s and progressive imbalance in their early 70s. Three of four affected had brief (minutes) episodes of vertigo typically occurring a few times per year. Auditory and vestibular function testing documented a slowly progressive loss of auditory and vestibular function. Postmortem examination showed a loss of hair cells in the cochlea and vestibular receptor organs. There were no cellular infiltrates or acidophilic deposits. No mutations were found in the COCH or MYO7A genes. Conclusions: This dominantly inherited audiovestibular syndrome results in a selective loss of hair cells in the auditory and vestibular end organs. Finding the causative gene could have important implications for understanding the pathophysiology of presbycusis and dysequilibrium of aging.