Familial progressive vestibulocochlear dysfunction caused by a COCH mutation (DFNA9)

Objective: To describe the decline of vestibulocochlear function in a man w ith vestibulocochlear dysfunction caused by a Pro51Ser mutation within the COCH gene on chromosome 14q12-13 (DFNA9). Methods: A follow-up of more than 15 years was performed in a single case. Clinical investigations were supplemented by oculomotor, vestibular, and au ditory tests. Results: A 50-year-old man had had progressive sensorineural hearing loss a nd dysequilibrium for 15 years; he had been asymptomatic at the age of 35 y ears. He suffered from instability in the dark, head movement-dependent osc illopsia, paroxysmal positional vertigo, and vertigo with and without nause a. Hearing impairment started unilaterally, predominantly in the high frequ encies. He also reported tinnitus. Disease progressed to severe bilateral h igh-frequency hearing impairment and vestibular areflexia. Fluctuation of v estibulocochlear function was documented and mentioned by the patient. Conclusions: Our patient proved to suffer from an autosomal dominant vestib ulocochlear disorder caused by a COCH gene mutation. The remarkable medical history has some features in common with Meniere disease; however, there a re also different clinical and neurophysiological features. In the family, phenotypic variability is present.