CMT 2L:Clinical, pathological and genetic studies in a Chinese family

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Zhejiang Da Xue Xue Bao Yi Xue Ban. 2005 Nov;34(6):529-33. Links

Clinical, pathological and genetic studies in a Chinese Charcot-Marie-

Tooth disease type 2 family.

Luo W, Tang YL, Tang BS, Ding MP, Zhao GH, Zhang BR, Xia K, Tang JG,

Zhang FF, Zhang RX, Yang QD.

Department of Neurology, The Second Affiliated Hospital, College of

Medicine, Zhejiang University, Hangzhou 310009, China.

OBJECTIVE: To report a Chinese Charcot-Marie-Tooth disease type 2

(CMT2) family.

METHODS: 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.

RESULT: 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.

CONCLUSION: The results are consistent with the diagnosis of CMT2.

This family represents a rare genetic type of CMT2 which can be

designated as CMT2L.