远端型遗传性运动神经病V型一家系

Distal hereditary motor neuropathy type V ：a report of a Chinese family

目的报道1个远端型遗传性运动神经病V型（dHMN—V）家系的临床、病理和基因改变特点。方法该家系中连续4代有9例（4例男性，5例女性）在13～40岁之间发病，其中6例出现下肢无力；有2例女性患者仅出现双手肌肉无力和萎缩，其中1例出现锥体束征。先证者为20岁女性，13岁时发现双手肌肉萎缩和无力，15岁后出现下肢无力；肌电图提示神经源性损伤，神经传导速度检查显示运动神经复合肌肉动作电位波幅显著降低，伴随传导速度轻度减慢，感觉神经传导速度和动作电位波幅均正常。对先证者进行腓肠神经活体组织病理检查，并对先证者和其他4例发病者进行血Berardinelli—Seip先天性脂肪营养不良基因2（BSCL2）基因检查。结果病理检查显示腓肠神经的有髓神经纤维数量轻度减少，伴随个别有髓神经纤维再生簇以及洋葱球样改变。基因检查显示BSCL2基因的第3号外显子存在263A→G杂合突变。结论临床和基因检查证实该家系为dHMN-V，其发病年龄和临床表现在同一家系中存在异质性，可以伴随轻微锥体束征和感觉神经损害。

Objective To report the clinical, pathological and genetic features in a Chinese family with distal hereditary motor neuropathy type V （ dHMN-V ）. Methods Four men and 5 women in 4 generations were involved. The onset of disease was from 13 to 40 years old. Six of them showed predominantly weakness of low extremities. Two women had only weakness and atrophy of hand muscle and 1 woman presented additionally pyramidal signs. The proband, a 20 year-old girl, presented asymmetrical atrophy and weakness of both hands since 13 years old. She had weakness of low extremities after 15 years old. Neurogenic changes were observed in the electromyography. Amplitude of compound muscle action potentials were markedly reduced, while the motor nerve conduction velocity were mildly decreased. Sensory nerve conduction velocity and amplitude of action potential were within the normal range. Sural nerve biopsy was performed in the proband. Berardinelli-Seip congenital lipodystrophy 2 （BSCL2） gene were sequenced in the proband and other 4 patients. Results Nerve biopsy showed mild loss of myelinated fibers with a few regeneration cluster of myelinated fibers. DNA analysis revealed a heterozygous 263A→G mutation in exon 3 of BSCL2 gene. Conclusions dHMN-V has been genetically and clinically confirmed in this family. The phynotypo is obviously heterogeneous in onset time and clinical symptoms within the same family. The patients present mild pyramidal tract signs and axonal lesions in the sensory nerve.