Yuan Ping, Jiang Li
M.S. Department of Neurology, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, China.
M.S. Department of Neurology, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, China.
Brain Dev. 2015 May;37(5):537-41. doi: 10.1016/j.braindev.2014.08.007. Epub 2014 Sep 15.
The severity of spinal muscular atrophy (SMA) is highly variable and children with heterogeneous clinical features can be classified into three phenotypes (type I-III) on the basis of age of onset and maximum motor function achieved. The aim of this study was to compare the clinical characteristics of three phenotypes in children with SMA.
One hundred and thirty-two SMA patients were classified as type I, II or III according to the SMA classification criteria. The clinical features, deletion of survival motor neuron 1 (SMN1) gene and electrophysiology were analyzed and compared. The survival and functional status were obtained through telephone follow up.
In our study, 90.6% of the patients lacked both copies of SMNl. No difference in the deletion frequency among the 3 groups was observed. Although most of the neurophysiological parameters showed no differences among the groups, the amplitudes of compound muscle action potential (CMAP) was lower in type III SMA. Absent sensory nerve action potential (SNAP) amplitude of the sural nerve was observed in 26 (25.4%) of the patients. The survival pattern and functional status of 66 cases were obtained. Two type II SMA patients could walk unaided during follow-up. The functional ability of lower extremities improved in 4 patients with type III SMA.
In this study, we confirm that EMG examination and homozygous deletion of SMN1 do not correlate with the subtypes. Motor function of patients with SMA type II and III can improve. A period of follow-up is necessary before rendering accurate classification and prognosis.
脊髓性肌萎缩症（SMA）的严重程度差异很大，具有异质性临床特征的儿童可根据发病年龄和所达到的最大运动功能分为三种表型（I - III型）。本研究的目的是比较SMA患儿三种表型的临床特征。
132例SMA患者根据SMA分类标准分为I型、II型或III型。对其临床特征、生存运动神经元1（SMN1）基因缺失情况及电生理进行分析比较。通过电话随访获取生存及功能状态。
在我们的研究中，90.6%的患者缺失SMN1的两个拷贝。3组间缺失频率未观察到差异。虽然大多数神经生理学参数在组间无差异，但III型SMA的复合肌肉动作电位（CMAP）波幅较低。26例（25.4%）患者腓肠神经感觉神经动作电位（SNAP）波幅缺失。获取了66例患者的生存模式和功能状态。2例II型SMA患者在随访期间能够独立行走。4例III型SMA患者下肢功能能力有所改善。
在本研究中，我们证实肌电图检查和SMN1纯合缺失与亚型无关。II型和III型SMA患者的运动功能可以改善。在进行准确分类和预后判断之前需要一段时间的随访。
