Cold extends electromyography distinction between ion channel mutations causing myotonla
Cold extends electromyography distinction between ion channel mutations causing myotonla
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DOI：
10.1002/ana.20905
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发表时间：
2006-09-01
影响因子：
11.2
通讯作者：
Fontaine, Bertrand
中科院分区：
文献类型：
--
作者：
Fournier, Emmanuel;Viala, Karine;Fontaine, Bertrand
目的：肌强直是骨骼肌兴奋性的遗传性疾病。非营养不良形式是由编码肌肉氯或钠通道的基因突变引起的。根据因果突变，肌强直会因反复运动而缓解或恶化，并且在暴露于寒冷时可能会合并为弛缓性无力。我们设计了一种简单的肌电图 (EMG) 方案，结合重复短时间运动和寒冷作为激发测试来区分突变组。方法：使用表面记录的复合肌肉动作电位来监测肌肉电活动。该方案应用于 31 名未受影响的对照受试者和 54 名已知会导致不同形式肌强直的氯离子或钠通道突变患者。结果：在患者中，室温下重复的短期运动测试揭示了复合肌肉动作电位变化 (I-III) 的三种不同的异常模式，这与临床症状相匹配。将反复运动与寒冷暴露相结合，以一种能够明确电生理学和遗传缺陷之间相关性的方式澄清了肌电图模式。解释：我们假设突变分离成不同的肌电图模式取决于潜在的病理生理学机制。结果使我们能够提出分子诊断的肌电图指南，该指南可用于临床实践。
Objective: Myotonias are inherited disorders of the skeletal muscle excitability. Nondystrophic forms are caused by mutations in genes coding for the muscle chloride or sodium channel. Myotonia is either relieved or worsened by repeated exercise and can merge into flaccid weakness during exposure to cold, according to causal mutations. We designed an easy electromyography (EMG) protocol combining repeated short exercise and cold as provocative tests to discriminate groups of mutations.Methods: Surface-recorded compound muscle action potential was used to monitor muscle electrical activity. The protocol was applied on 31 unaffected control subjects and on a large population of 54 patients with chloride or sodium channel mutations known to cause the different forms of myotonia.Results: In patients, repeated short exercise test at room temperature disclosed three distinct abnormal patterns of compound muscle action potential changes (I-III), which matched the clinical symptoms. Combining repeated exercise with cold exposure clarified the EMG patterns in a way that enabled a clear correlation between the electrophysiological and genetic defects.Interpretation: We hypothesize that segregation of mutations into the different EMG patterns depended on the underlying pathophysiological mechanisms. Results allow us to suggest EMG guidelines for the molecular diagnosis, which can be used in clinical practice.