Selective Bilateral Vestibular Neuropathy in a Turkish CMT1B Family With a Novel MPZ Mutation

Abstract

Purpose of reviewTo report findings in 12 members over 3 generations of a family with dominantly inherited Charcot Marie Tooth disease (CMT1B) due to a novel MPZ mutation, who all had moderately severe, selective impairment of vestibular function with normal hearing. Methods used were video head impulse testing of the function of all 6 semicircular canals, Romberg test on foam, nerve conduction studies, whole exome and Sanger sequencing.Recent findingsAll affected patients had a demyelinating neuropathy and a novel MPZ mutation: c.362A>G (chr1: 161276584, p.D121G). All also had normal hearing for age but a moderately severe impairment of semicircular canal function and a positive Romberg test on foam.SummarySome CMT mutations can impair vestibular function, presumably due a vestibular nerve involvement but spare hearing. In such patients impairment of vestibular function as well as impairment of proprioception contributes to imbalance.