A 26-year-old woman (patient 1 on the family tree—figure 1) gave a 6-year history of dysarthria, occasional jerks and progressive gait unsteadiness with frequent falls, and had become bedridden. On examination, she had dorsal kyphosis and pes cavus. There was severe truncal and appendicular ataxia, generalised action myoclonus, hyporeflexia, hypotonia and bilateral extensor plantar reflexes. Electromyography with nerve conduction studies identified a sensorimotor polyneuropathy, with intermediate conduction velocities. Figure 1 Family tree depicting genetic and phenotypic status of the family members. Her medical history was unremarkable, with a normal development. She had experienced one recent generalised tonic–clonic seizure. She had an older sister (patient 2 on the family tree—figure 1) with a rapidly progressive nephrotic syndrome starting at the age of 17, becoming steroid resistant and needing haemodialysis after a few months. She also had a normal development and unremarkable medical history. At age of 21, she had developed action myoclonus of the lower limbs, with subjective loss of strength and frequent falls, later progressing to the upper limbs. She started having generalised tonicclonic seizures and lost walking ability in the next year. At aged 28 years, she underwent renal transplantation and died 5 years later due to graft-related complications. Their parents were consanguineous (they were half-siblings) and they had a healthy sister. ### How can you localise her myoclonus and what should be the initial steps in the evaluation? Clinical assessment of pathological myoclonus requires a systematic approach. On neurological examination, it is important to note if the myoclonus appears at rest, on posture or during action. If present at rest, a spinal or brainstem source is more likely, whereas, if action induced, a cortical source should be suspected. Distribution is also important: cortical myoclonus is typically focal or multifocal, spinal segmental myoclonus can also be focal (but usually is stimulus sensitive and not action induced), while generalised myoclonus is generally subcortical (brainstem or propriospinal). Generalised myoclonus …

中文翻译：

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患有肌阵挛和共济失调的两姐妹

一名 26 岁女性（家谱中的患者 1 - 图 1）有 6 年构音障碍病史，偶尔抽搐，步态不稳，经常跌倒，卧床不起。在检查时，她有背侧后凸和 pes cavus。出现严重的躯干和四肢共济失调、全身性肌阵挛、反射减退、肌张力减退和双侧伸肌足底反射。带有神经传导研究的肌电图确定了一种感觉运动性多发性神经病，具有中等传导速度。图 1 描述家族成员遗传和表型状态的家谱。她的病史无异常，发育正常。她最近经历了一次全身性强直-阵挛发作。她有一个姐姐（家谱中的患者 2 - 图 1），从 17 岁开始患有快速进展的肾病综合征，几个月后变得类固醇耐药并需要进行血液透析。她也有正常的发育和不起眼的病史。21岁时出现下肢动作性肌阵挛，主观上失去力量，经常跌倒，后来发展到上肢。第二年，她开始出现全身性强直痉挛发作并丧失行走能力。28 岁时，她接受了肾移植，5 年后因移植相关并发症死亡。他们的父母是近亲（他们是同父异母的兄弟姐妹），他们有一个健康的妹妹。### 你如何定位她的肌阵挛，评估的初始步骤应该是什么？病理性肌阵挛的临床评估需要系统的方法。在神经系统检查中，重要的是要注意肌阵挛是否出现在静止、姿势或动作过程中。如果在休息时存在，则更有可能是脊髓或脑干来源，而如果引起动作，则应怀疑皮质来源。分布也很重要：皮层肌阵挛通常是局灶性或多灶性的，脊髓节段性肌阵挛也可以是局灶性的（但通常对刺激敏感而不是动作诱发），而全身性肌阵挛通常在皮层下（脑干或脊髓本体）。广泛性肌阵挛… 在姿势或动作中。如果在休息时存在，则更有可能是脊髓或脑干来源，而如果引起动作，则应怀疑皮质来源。分布也很重要：皮层肌阵挛通常是局灶性或多灶性的，脊髓节段性肌阵挛也可以是局灶性的（但通常对刺激敏感而不是动作诱发），而全身性肌阵挛通常在皮层下（脑干或脊髓本体）。广泛性肌阵挛… 在姿势或动作中。如果在休息时存在，则更有可能是脊髓或脑干来源，而如果引起动作，则应怀疑皮质来源。分布也很重要：皮层肌阵挛通常是局灶性或多灶性的，脊髓节段性肌阵挛也可以是局灶性的（但通常对刺激敏感而不是动作诱发），而全身性肌阵挛通常在皮层下（脑干或脊髓本体）。广泛性肌阵挛… 而全身性肌阵挛通常位于皮层下（脑干或脊髓本体）。广泛性肌阵挛… 而全身性肌阵挛通常位于皮层下（脑干或脊髓本体）。广泛性肌阵挛…