[Clinical, pathological and genetic studies in a Chinese Charcot-Marie-Tooth disease type 2 family].
To report a Chinese Charcot-Marie-Tooth disease type 2 (CMT2) family.



All the members in the family were studied clinically,and 6 patients were studied electrophysiologically. Sural nerve biopsy was performed in the proband. PMP22 gene duplications were detected by highly polymorphic short tandem repeat. Point mutation analysis of PMP22, MPZ and NEFL gene was screened by PCR-SSCP combined with DNA direct sequencing. A genome-wide screening was carried out to the family.



Except 2 who had weakness and atrophy in both proximal and distal muscles of the lower limbs, all patients presented muscle wasting and a predominating weakness of distal parts of the lower limbs, and mild to moderate sensory impairments. In 6 patients who were subjected to elctrophysiological examinations, median-nerve conduction velocity (NCV) of the median nerve was normal. Electromyograms (EMGs) revealed signs of denervation with large motor unit potentials, fibrillation potentials and positive sharp waves. Sural nerve biopsy of the proband confirmed the presence of axonal neuropathy with an important loss of large myelinating fibers and a large number of clusters with mostly thinly myelinated axons. PMP22, MPZ and NEFL gene mutations were not found. The results of genome-wide screening revealed a linkage of CMT2 to a locus at chromosome 12q24.



The results are consistent with the diagnosis of CMT2. This family represents a rare genetic type of CMT2 which can be designated as CMT2L.
Luo
Wei
W
Department of Neurology, The Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310009, China.
Tang
Ye-Lei
YL
Tang
Bei-sha
BS
Ding
Mei-ping
MP
Zhao
Guo-hua
GH
Zhang
Bao-rong
BR
Xia
Kun
K
Tang
Jian-guang
JG
Zhang
Fu-feng
FF
Zhang
Ru-xu
RX
Yang
Qi-dong
QD
D000293:Adolescent; D000328:Adult; D044466:Asian People; D002607:Charcot-Marie-Tooth Disease / Q000235:genetics* / Q000473:pathology*; D002881:Chromosomes, Human, Pair 12 / Q000235:genetics*; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D010375:Pedigree