Comparison of Clinical and Electrophysiological Characteristics between CMTX with Cx32 Missense Mutation and CMT1A with PMP22 Duplication

J Korean Neurol Assoc > Volume 22(3); 2004 > Article

Journal of the Korean Neurological Association 2004;22(3): 226-234.

Cx32 유전자 돌연변이를 보인 CMTX와 PMP22 유전자 중복을 보인 CMT1A 환자들의 임상 및 전기생리학적 특성 비교

최병옥, 정기화 박기덕 김승민 신상희 선우일남

이화여자대학교 의과대학 신경과학교실, 공주대학교 생명과학과*, 연세대학교 의과대학 신경과학교실

Comparison of Clinical and Electrophysiological Characteristics between CMTX with Cx32 Missense Mutation and CMT1A with PMP22 Duplication

Byung-Ok Choi

Department of Neurology, Ewha Womans University College of Medicine, Seoul; Department of Biological Science, Kongju National University*, Gongju; Department of Neurology, Yonsei University College of Medicine†, Seoul, Korea

Abstract

Background: Charcot-Marie-Tooth (CMT) disease is a clinically and genetically heterogeneous disorder. Connexin32 (Cx32) gene mutations on Xq13.1 cause the X-linked form of CMT disease, and PMP22 gene duplication on 17p11.2-p12 causes CMT1A. The aim of the present study is to determine the clinical and electrophysiological characteristics between X-linked CMT patients with Cx32 missense mutations and CMT1A patients with PMP22 duplications.
Methods: We screened for 17p11.2-p12 duplication, and for point mutations in Cx32 genes of 48 Korean CMT families. Both neurological examination and nerve conduction studies were performed in all patients.
Results: Frequency of CMTX (6.3%) in our study was similar to Japanese, and was lower than those in European peoples. CMTX patients displayed no man-to-man transmission, and had cranial nerve involvement. CMTX patients showed more wide range of motor and sensory nerve conduction velocities than CMT1A patients. We found one family with axonal neuropathy and two families with demyelinating neuropathy in CMTX patients.
Conclusions: Our findings suggest that mutations in Cx32 are probably less frequent in Asian CMT patients than European patients, and CMTX neuropathy is intermediary between CMT1 and CMT2. In addition, inheritance pattern and cranial nerve involvement are useful in differentiating CMTX from CMT1A with duplication.Key Words: Charcot-Marei-Tooth disease, Cx32, PMP22, CMTX, Mutation