临床资料男，8岁，河北省清河人，因发作性四肢无力3次就诊。患儿子3月前无明显诱因在上课时自觉双下肢无力、站立困难，继之双手无力，不能持笔写字，持续1小时自行缓解。每月发作1次，均在白天发作，不伴意识丧失。既往身体健康，无头部外伤史，家族中直系三代均无类似发作者 Clinical data Male, 8 years old, Qinghe, Hebei Province, due to the onset of limb weakness 3 times treatment. Suffering from his son 3 months ago no obvious incentive to consciously lower limb weakness in class, standing difficulties, followed by weakness in his hands, can not hold pen and writing, sustained 1 hour to ease. 1 episode per month, all during the day attack, without loss of consciousness. Past physical health, no history of head trauma, the family did not directly send three generations of similar fathers