儿童型脊肌萎缩症肌电图特征及基因诊断  

Electromyogram Characteristics and Gene Diagnosis in Child Type of Spinal Muscular Atrophy

作　　者：王春芝[1] 牟海燕[1] 丁勇民[1] 

机构地区：[1]南昌大学第二附属医院神经内科,南昌330006

出　　处：《实用儿科临床杂志》2008年第12期906-907,共2页Journal of Applied Clinical Pediatrics

摘　　要：目的探讨儿童型脊肌萎缩症(SMA)神经电生理特征和基因诊断及产前诊断的临床意义,以提高对本病的认识。方法收集SMA患儿15例。男9例,女6例;发病年龄5个月～12岁。根据发病年龄和病程临床分为3型。其中SMAⅠ型5例。男3例,女2例;年龄5～18个月。SMAⅡ型7例。男4例,女3例;年龄12个月～3岁。SMAⅢ型3例。男2例,女1例;年龄3～12岁。3型SMA各有特点,但临床均表现为近端肌无力伴肌萎缩,肌张力明显低下和自主运动丧失,不能坐或站立。应用丹麦产MedocKeypoint肌电/诱发电位仪对15例SMA患儿进行肌电图(EMG)、神经传导速度测定。采用PCR-酶切分析法对患儿进行运动神经元生存基因(SMN)检测。结果EMG自发电位平均出现率为94%,运动单位电位平均时限增宽90%,波幅平均增高89%。78条运动神经检测结果显示52条神经肌肉复合动作电位波幅衰减,其中36条并末端潜伏期延长及运动传导速度轻度减慢。所测45条感觉神经的传导速度在正常范围。10例患儿行SMN检测,9例患儿缺失SMN第7、8号外显子,1例仅缺失第7号外显子。10例患儿父母进行SMN基因检测,未发现SMN第7、8号外显子缺失。结论SMA确诊有赖于典型的临床和电生理特点及基因诊断。基因诊断可为产前诊断提供依据。Objective To explore the importance of gene diagnosis and prenatal diagnosis of spinal muscular atrophy （SMA） , and improve the clinical diagnosis of SMA by analyzing the electrophysiological and gene characteristics of SMA. Methods Fifteen cases with SMA including 9 male and 6 female were enrolled in this study. The age was 5 months to 12 years. The 15 cases were subdivided into 3 clinical types ,5 cases of type I including 3 male and 2 female aging 5 - 18 months ; 7 cases of type Ⅱ including 4 males and 3 females aging 5 months - 3 years;3 cases of type m including 2 male and 1 female aging 3 - 12 years. They were all characterized by symmetric muscle weakness （ more proximal than distal） associated with atrophy, absence or marked decrease of deep tendon reflexes ,loss of voluntary movement and inability to sit or stand. The clinical characteristics and changes of electromyography （EMG） and nerve conduction velocity were assessed in all cases by using Danish Medoc Keypoint myoelectricity and evoked potentials inducer. The survival of motor neuron （SMN） gene was detected by PCR and restriction endonuclease spectrum analysis in 10 cases. Results EMG analysis found 94% patients had spontaneous potential, 90% patients had increased duration of motor unit, and amplitude increased in 89% patients. Motor nerve conduction velocity was determined in 78 nerves. Motor nerve compound action potential wave amplitude decreased in 52 nerves, among them, distal latent period prolonged and motor conduction velocity reduced slightly in 36 nerves. Sensory nerve conduction velocity was determined in 45 nerves and remained normal. The SMN gene detection revealed deletion of exon 7 and 8 in 9 cases, deletion exon 7 in 1 case. The SMN gene detection in 10 patients and their parents didn＇t find any deletion of exon 7 and 8. Conclusions The definite diagnosis of SMA will rely on the typical clinical characteristics, changes of EMG and gene deletion analysis. Gene diagnosis of SMA lays a basis for prenatal diagnosis.

关 键 词：脊髓性肌萎缩 诊断 儿童 

分 类 号：R746[医药卫生—神经病学与精神病学]