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Differential electrophysiological features of neuropathies associated with 17p11.2 deletion and duplication
Author(s) -
Uncini Antonio,
Di Guglielmo Giovanni,
Di Muzio Antonio,
Gambi Domenico,
Sabatelli Mario,
Mignogna Teresa,
Tonali Pietro,
Marzella Rosalia,
Finelli Palma,
Archidiacono Nicoletta,
Rocchi Mariano
Publication year - 1995
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/mus.880180610
Subject(s) - peripheral myelin protein 22 , gene duplication , electrophysiology , medicine , pathology , myelin , hereditary motor and sensory neuropathy , compound muscle action potential , anatomy , neuroscience , gene , biology , genetics , central nervous system , disease
Hereditary neuropathy with liability to pressure palsies (HNPP) and hereditary motor‐sensory neuropathy type IA (HMSN IA) are quite distinct clinical entities recently associated to deletion and duplication, respectively, of the 17p11.2 segment including the gene for peripheral myelin protein 22 (PMP‐22). We studied the electrophysiological features of 48 HNPP and 62 HMSN IA motor nerves. Conduction velocities (CV) and compound muscle action potential amplitudes were significantly reduced and distal latencies prolonged in HMSN IA compared to HNPP. CV was uniformly slowed in HMSN IA nerves whereas in HNPP it was focally slowed in 80% of ulnar and 12% of peroneal nerves at usual compression sites. Conduction block was present in 6% of HNPP nerves but in none of HMSN IA. In conclusion: (1) HMSN IA with 17p11.2 duplication presents marked, diffuse, and uniform slowing; (2) HNPP with 17p11.2 deletion presents focal electrophysiological abnormalities possibly correlated with the presence of tomaculae; and (3) under‐and overexpression of PMP‐22 in concurrence with environmental factors might be responsible for the distinctive features of HNPP and HMSN IA. © 1995 John Wiley & Sons, Inc.