Hereditary auditory, vestibular, motor, and sensory neuropathy in a Slovenian Roma (Gypsy) kindred

Members of a Roma (Gypsy) family with hereditary motor and sensory peripher al neuropathy (HMSN) and concomitant auditory and vestibular cranial neurop athies were identified in Kocevje, Slovenia. The illness begins in childhoo d with a severe and progressive motor disability and the deafness is delaye d until the second decade. There are no symptoms of vestibular dysfunction. The family structure is consistent with an autosomal recessive pattern of inheritance and the genetic locus for the disorder is linked to the same re gion of chromosome 8q24 as other Roma families with HMSN and deafness from Lom, Bulgaria (KMSN-Lom). The present study shows that the deafness is caus ed by a neuropathy of the auditory nerve with preserved measures of cochlea r outer hair cell function (otoacoustic emissions and cochlear microphonics ) but absent neural components of auditory brainstem potentials. The hearin g loss affects speech comprehension out of proportion to the pure tone loss . Vestibular testing showed absence of caloric responses. Physiological and neuropathological studies of peripheral nerves were compatible with the ne rve disorder contemporaneously affecting Schwann cells and axons resulting in both slowed nerve conduction and axonal loss. Genetic linkage studies su ggest a refinement of the 8q24 critical region containing the HMSN-Lom locu s that affects peripheral motor and sensory nerves as well as the cranial a uditory and vestibular nerves.