[Phenotype study of SCN2A gene related epilepsy].

Objective: To summarize the phenotype of epileptic children with SCN2A mutations. Methods: Epileptic patients who were treated in the Pediatric Department of Peking University First Hospital from September 2006 to October 2017 and detected with SCN2A mutations by targeted next-generation sequencing were enrolled. Clinical manifestations of all patients were analyzed retrospectively. Results: A total of 21 patients (16 boys and 5 girls) with SCN2A mutations were collected. Twenty-one SCN2A mutations were identified. Ten patients had mutations inherited from one of their parents and 11 patients had de novo mutations. The age of epilepsy onset was from 2 days to 2 years and 6 months: six patients with seizure onset in neonates (29%) , six patients with seizure onset between 1 month and 3 months of age (29%), three patients with seizure onset between 4 months and 6 months of age, two patients with seizure onset between 7 months and one year of age, and four patients with seizure onset beyond one year of age. Multiple seizure types were observed. The focal seizure was the most common seizure type which was observed in 18 patients (86%) . Spasm seizure was observed in 6 patients (29%) . Other seizure types were rare. In 19 patients, seizures manifested in clusters (90%) . In 3 patients, seizures manifested fever-sensitive. Nine of ten patients with inherited SCN2A mutations had normal development. However, all patients with de novo SCN2A mutations had mild or severer development delay. In 21 patients with SCN2A mutations, five were diagnosed with benign familial infantile epilepsy, 3 with benign familial neonatal-infantile epilepsy, 3 with Ohtahara syndrome, 3 with West syndrome, 2 with encephalopathy with early infantile onset epilepsy, one with febrile seizures plus, one with Dravet syndrome, one with encephalopathy with childhood-onset epilepsy, one with autism with epilepsy and one with intellectual disability with epilepsy. Conclusions: The clinical features of patients with SCN2A mutations include that main seizure onset is the neonate and early infancy, and the main seizure type is the focal seizure, manifested in clusters. The large spectrum of SCN2A-related epilepsy, which not only includes epilepsy with a comparatively favorable prognosis, but also epileptic encephalopathy. De novo mutations often lead to severe phenotype with development delay.目的： 总结SCN2A基因突变导致的癫痫表型谱。 方法： 收集2006年9月至2017年10月在北京大学第一医院儿科诊治的癫痫患儿，且通过靶向捕获二代测序发现SCN2A基因突变阳性者，回顾性总结和分析患儿临床特点。 结果： 共收集21例SCN2A基因突变阳性的患儿，其中男16例、女5例，检测到21种不同的突变类型，其中11例为新生突变，10例为遗传性突变。21例患儿的癫痫发作起病年龄为2日龄~2岁6月龄，其中新生儿期起病6例（29%），1~3月龄起病6例（29%），4~6月龄起病3例，7月龄~1岁起病2例，1岁后起病4例；表现为多种发作类型，其中局灶性发作18例（86%），痉挛发作6例（29%），其他发作类型少见；19例患儿发作有丛集性的特点（90%）；3例患儿发作有热敏感。10例携带SCN2A基因遗传性突变的患儿中，9例智力、运动发育正常；11例携带SCN2A基因新生突变的患儿均有不同程度的智力、运动发育落后。21例患儿包括多种癫痫表型，其中良性家族性婴儿癫痫5例，良性家族性新生儿-婴儿癫痫3例，大田原综合征3例，婴儿痉挛症3例，不能分类的早发癫痫性脑病2例，热性惊厥附加症1例，Dravet综合征1例，儿童期起病的癫痫性脑病1例，孤独症共患癫痫1例，发育落后共患癫痫1例。 结论： SCN2A基因突变导致的癫痫多在新生儿期或婴儿早期起病，发作具有丛集性的特点，局灶性发作最常见；癫痫表型谱广，既可表现为良性预后的癫痫，也可表现为癫痫性脑病，新生突变的患儿表型重，常伴智力、运动发育落后。.