Pathology and physiology of auditory neuropathy with a novel mutation in the MPZ gene (Tyr145->Ser).
We studied a family with hereditary sensory motor neuropathy and deafness accompanying a missense mutation in the MPZ gene. Pathological examination of the cochlea in one of the family members revealed marked loss of auditory ganglion cells and central and peripheral auditory nerve fibres within the cochlea. The inner hair cells were of normal number with preserved morphology. The outer hair cells were normal in number except for a 30% reduction in just the apical turn. Examination of the sural nerve and the auditory nerve adjacent to the brainstem showed marked loss of fibres with evidence of incomplete remyelination of some of the remaining fibres. Studies of auditory function in surviving family members using electrophysiological and psychoacoustic methods provided evidence that the hearing deficits in this form of auditory neuropathy were probably related to a decrease of auditory nerve input accompanying axonal disease. Altered synchrony of discharge of the remaining fibres was a possible additional contributing factor.
Starr
Arnold
A
Department of Neurology, University of California Irvine, CA 92697-4290, USA. astarr@uci.edu
Michalewski
Henry J
HJ
Zeng
Fan-Gang
FG
Fujikawa-Brooks
Sharon
S
Linthicum
Fred
F
Kim
Chong S
CS
Winnier
Deidre
D
Keats
Bronya
B
D000368:Aged; D003051:Cochlea / Q000473:pathology; D006319:Hearing Loss, Sensorineural / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D015417:Hereditary Sensory and Motor Neuropathy / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008875:Middle Aged; D020125:Mutation, Missense; D018993:Myelin P0 Protein / Q000235:genetics*; D009412:Nerve Fibers / Q000473:pathology; D010375:Pedigree; D011571:Psychoacoustics; D013497:Sural Nerve / Q000473:pathology
D018993:Myelin P0 Protein