基因重复的进行性腓骨肌萎缩症1A型临床与电生理研究

摘要

Objective 　To study the clinical and electrophysiological features in Charcot-Marie-Tooth disease type 1A with gene duplication.Methods　Clinical symptoms and signs were summarized in 22 patients from 21 unrelated families. Electromyography (EMG) as well as motor conduction velocities (MCV) and sensory conduction velocities (SCV) examinations were performed in all patients. Results　Evidence of CMT was initially detected within the second decade in 18 patients. Nearly half of patients were sporadic cases. The typical clinical manifestations of CMT1A were weakness and atrophy in the distal limbs, weakness or absence of the tendon reflexes, talipes equinovarus and postural tremor the upper limb. Additionally, some special symptoms and signs were also observed occasionally, including brisk tendon reflexes, extensor plantar responses, scoliosis, foot ulcers and nystagmus. EMG revealed that 77.3% of the patients had fibrillation and positive sharp potentials. 81.8% of them had prolonged motor unit potential limit. Median MCV showed there was no significant difference between CMT1A patients and CMT1 patients without duplication (t=1.63, P＞0.05). Values of SCV and MCV for the lower limbs were not obtained in 20 patients and more than 2/3 of the patients respectively. Conclusions　The clinical features of CMT1A included high frequent of sporadic cases, early onset in the second decade and various manifestations. The electrophysiological features were that the damages of nerves for the lower limbs were more severer than those in the upper limbs and the damages of the sensory nerves were more severer than those of the motor nerves. The phenotype was variable although the genotype was the same in CMT1A patients with PMP22 duplication.%目的研究有基因重复的进行性腓骨肌萎缩症1A型(Charcot-Marie-Tooth病1A，CMT1A)临床与电生理特点。方法对来自21个家系的22名CMT1A病人临床特点进行总结，同时分析其电生理特征，包括肌电图(EMG)、运动神经传导速度(MCV)和感觉神经传导速度(SCV)。结果 18例病人20岁以前发病；20例为散发；均具有肢体远端肌肉无力和萎缩、腱反射减弱或消失、足畸形和上肢姿势震颤等典型的临床表现，偶尔合并膝腱反射活跃、病理征阳性、脊柱侧弯、足部溃疡和眼震等。17/22的病人肌电图上出现纤颤、正相电位，18/22的病人运动单位电位时限延长。有基因重复的CMT1A病人正中神经MCV与无基因重复的CMT1A病人无显著性差异。20/22的病人下肢SCV引不出，2/3以上病人下肢MCV引不出。结论本组病人散发病例多，临床表现差异较大。电生理特点为下肢神经病变重于上肢，感觉神经病变重于运动神经。CMT1A病人虽然基因型相同，表现型却存在差异。