Neural electrophysiological features and gene diagnosis of 85 patients with spinal muscular atrophy
10.3760/cma.j.issn.1671-8925.2016.10.012
- VernacularTitle:85例脊髓性肌萎缩症临床、神经电生理特征与基因诊断分析
- Author:
Yunqian ZHANG
1
;
Yinhong ZHANG
;
Xuan HE
;
Xiaomin ZHANG
;
Tingjuan WANG
;
Jianlin WANG
Author Information
1. 昆明医科大学第四附属医院神经内科
- Keywords:
Muscular atrophy,spinal;
Electromyography;
Nerve conduction;
Gene
- From:
Chinese Journal of Neuromedicine
2016;15(10):1036-1041
- CountryChina
- Language:Chinese
-
Abstract:
Objective To explore the relations of clinical phenotypes of type Ⅰ-ⅣV spinal muscular atrophy (SMA) with neural electrophysiological features and survival motor neuron (SMN)gene.Methods A total of 85 patients with SMA,including 46 with infantile form in which 19 of type Ⅰ and 27 of type Ⅱ,24 with juvenile form (type Ⅲ),and 15 with adult form (type ⅣV),were involved in this clinical study.Their clinical data were analyzed.The neural conduction,needle electromyography (EMG)and SMN1 gene deletion were analyzed.Results There existed different clinical features among patients who suffered from type Ⅰ to type ⅣV SMA.However,the major clinical features of SMA were displayed by progressively aggravating of flaccid paralysis in muscles of the four limbs,and the younger of the patients,the more serious of the clinical manifestations.EMG exhibited neurogenic lesion in all 43 SMA patients,33 patients presented generalized neurogenic lesions,and the abnormal degree of muscles in lower limbs was more severe than that of upper limbs,and the proximal muscles was more severe than that of the distal ones.The abnormal rate of spontaneous potential,weak contraction with raise potential and amplitude of compound motor active potential in adult and juvenile SMA were significantly lower than those in infantile SMA.SMN1 gene exon 7 and 8 were detected in all 85 patients with SMA.A total of 61 patients were found with deletion of exon 7 and/or 8 in SMN1 gene.Infantile SMA patients enjoyed 95.7％ (44/46) detection rate,juvenile SMA patients enjoyed 70.8％ (17/24) detection rate;no adult SMA patients were found with deletion ofexon 7 and/or 8 in SMN1 gene.Conclusions The more serious of clinical manifestations in SMA patients,the higher abnormality rote in electrophysiological tests.The exons deletion in SMN1 gene could result in alterations of SMA phenotypes,but it has nothing to do with the severity of SMA.Gene deletion analysis of SMN1 gene can be considered as the preferred fimal diagnosis method for infantile SMA patients.But as for juvenile form,its diagnosis depending on gene deletion analysis of SMN1 gene will be analyzed with precaution.While as for adult form of SMA,the incidence of SMA may be independent with SMN1 gene deletion.Therefore,generally,SMN1 gene assay is not taken as the routine diagnose method for adult form SMA.
