X连锁腓骨肌萎缩症Cx32基因的突变、临床和电生理特点

目的 分析X连锁腓骨肌萎缩症（CMTX）患者Cx32基凶的突变及其临床表现和电生理特点、方法应用多聚酶链反应一单链构象多态性分析结合DNA直接测序的方法，对24例无周围髓鞘蛋白（PMP）22基因大片段重复突变，家系中无男传男的腓骨肌萎缩症（CMT）先证者进行Cx32基因的突变分析；对先证者及其家系内患者进行临床和电生理检查。结果 在6个X连锁遗传家系和1例散发患者中发现了7个不同的Cx32基因突变，其中4个家系临床分型为CMTI型，2个家系为CMT中间型，散发病例为CMT1型检测到有Cx32基因突变的家系成员共38例，其巾男性20例，全部为CMTX患者；女性18例，其中6例为CMTX患者，12例为无临床症状的携带者；26例患者均为周围神经轻、中度受累。结论 CMTX的遗传方式可为X连锁显性、X连锁隐性遗传，也可为散发。根据临床和电生理特点分为CMTI型或CMT中间型，多为周围神经轻、中度受累，男性患者的症状通常较女性重。在没有检测到PMP22基因大片段重复突变和无男传男的CMT家系中应首先进行Cx32基因突变分析。

Mutation of Cx32 gene, clinical and electrophysiological features in patients with Charcot-Marie-Tooth disease

Objective To investigate the mutation of Cx32 gene,clinical and electrophysiological features of Chinese patients with Charcot-Marie-Tooth(CMT) disease.Methods 24 CMT probands were selected for Cx32 mutation screening after the exclusion of the CMT1A 1.5 Mb duplication and male-to-male transmission.The motor and sensory nerve conduction studies were performed in all probands and most of their affected family members to establish the clinical CMT1,CMT2 or CMT intermediate diagnosis.The presence of mutations in the coding region of Cx32 was detected by single-strand conformation polymorphism analysis combined with direct sequencing.Results It was found 7 different point mutations in the coding region of Cx32 in 1 sporadic CMT1 patient and 6 X-linked inherited families,including 4 families with CMT1 diagnosis and 2 families with CMT intermediate diagnosis.There were 20 male CMTX patients,6 female CMTX patients and 12 asymptomatic female carriers among 38 family members bearing Cx32 mutation.All of the 26 patients were mildly to moderately affected clinically.Conclusions Seven different Cx32 point mutations were detected and the percentage of Chinese CMT families with Cx32 mutation is about 10% in our study.The inheritance model of CMT secondary to Cx32 mutation could be X-linked dominant,X-linked recessive or sporadic.Male patients are usually more severly affected than females with slower nerve conduction velocities.Cx32 mutation screening should be firstly performed in those CMT families without male-to-male transmission and CMT1A duplication.