患儿,女,15岁,因发育迟缓14年,运动及认知明显倒退1年余就诊。患儿临床特征为肌阵挛,意向性震颤,共济失调,腱反射亢进,肌张力增高,构音障碍,言语倒退,智力障碍,多灶性癫痫发作,脑电图典型痫性放电,癫痫难治。患儿自幼发育迟缓,逐渐走路步态不稳,行走困难,伴四肢震颤,除了癫痫发作外,语言及认知倒退明显。基因检测发现患儿SEMA6B基因的1个变异,结合遗传学特点及临床表型,判定为致病性变异,确诊为进行性肌阵挛性癫痫（PME）。PME的治疗基本上为抗癫痫发作,以及姑息支持和康复措施。大多预后不良。基因检测有助于难治性癫痫患儿的诊断和治疗。SEMA6B基因变异可导致PME表型,该患儿基因变异〔c.2149（exon17）C>T〕以往未见报道,扩充了PME的基因变异谱。

A 15-year-old female patient was admitted to the hospital due to developmental retardation for 14 years and significant motor and cognitive regression for more than 1 year. The clinical features of this patient were myoclonus, intention tremor, ataxia, tendon hyperreflexia, hypertonia, dysarthria, speech regression, intellectual disability and multifocal seizures. Electroencephalogram showed typical epileptic discharge and the epilepsy was refractory. The patient had developmental retardation since childhood. Walking gait instability gradually aggravated, and eventually developed into walking difficulties with tremor of limbs. In addition of seizures, language and cognitive regression of the patient was evident. Genetic testing found a variation of SEMA6B gene in the child, which was determined as a pathogenic variation combined with genetic characteristics and clinical phenotype, and the child was diagnosed as progressive myoclonic epilepsy (PME). Treatment of PME is generally anti-seizure, as well as palliative support and rehabilitation measures. Most patients have poor prognosis. Genetic testing contributes to the diagnosis and treatment of patients with refractory epilepsy. SEMA6B gene variation can lead to PME phenotype. The gene variation C.2149 (exon17) C>T has not been reported before, which expands the gene variation spectrum of PME.