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Demyelinating X‐linked Charcot–Marie–Tooth disease: Unusual electrophysiological findings
Author(s) -
Tabaraud F.,
Lagrange E.,
Sindou P.,
Vandenberghe A.,
Levy N.,
Vallat J.M.
Publication year - 1999
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/(sici)1097-4598(199910)22:10<1442::aid-mus16>3.0.co;2-6
Subject(s) - tooth disease , electrophysiology , connexin 32 , nerve biopsy , medicine , pathology , disease , connexin , peripheral neuropathy , biology , genetics , gap junction , endocrinology , intracellular , diabetes mellitus
X‐linked Charcot–Marie–Tooth disease (CMT‐X) is caused by mutations of connexin‐32 (Cx‐32), which encodes a gap‐junction protein. Whether the neuropathy is primarily demyelinative or axonal remains to be established. We report findings of prominent demyelination in a 71‐year‐old woman with late‐onset disease. Electrophysiological studies revealed a nonuniform slowing of motor conduction velocities and dispersion of compound action potentials indicative of a demyelinating process which was confirmed by nerve biopsy. Such electrophysiological features are unusual in hereditary neuropathies and are more commonly found with acquired chronic demyelinating neuropathies. A systematic search confirmed the molecular genomic diagnosis of CMT‐X, illustrating the value of such tests in sporadic cases. Severity of clinical symptoms and signs may vary with age and sex of the patient. The pathology of CMT‐X in other reported cases has been variably interpreted as axonal, demyelinating, or showing both features. Our observations emphasize the demyelinative nature. © 1999 John Wiley & Sons, Inc. Muscle Nerve 22: 1442–1447, 1999