目的 探讨KCNQ2基因（OMIM#602235）变异癫痫患儿的临床表型及基因特点。方法 回顾性分析2018年10月至2022年11月经外显子测序发现的KCNQ2基因阳性癫痫患儿的临床资料，总结基因型特点及治疗情况。结果 24例KCNQ2基因变异（NM_172107）癫痫患儿中，男14例、女10例。癫痫首次发作年龄为生后17小时~5岁，其中≤6个月的16例（66.7%）。根据临床预后分为良性家族性新生儿癫痫（BFNE）1例，良性家族性婴儿癫痫（BFIE）6例，不能分类的自限性癫痫综合征4例；KCNQ2-发育性癫痫性脑病（KCNQ2-DEE）13例。基因变异以错义突变为主（62.5%），同时发现7个新的KCNQ2突变位点，其中c.1411C>T评估为致病性变异，c.602G>C、c.1031G>A、c.2159_2173del（p.720_725delinsR）评估为可疑致病变异。24例患儿的中位随访时间为40个月，13例KCNQ2-DEE存在不同程度的发育迟缓，其余11例总体预后较好，认知发育正常。结论 KCNQ2变异患儿癫痫发病年龄主要为新生儿期及婴儿早期。KCNQ2-DEE预后差。建议婴幼儿期不明原因的癫痫发作应尽早行基因检测，以明确诊断。

Objective To investigate the clinical and genetic characteristics of children with epilepsy caused by variations of the KCNQ2 gene (OMIM #602235). Methods The clinical data of 24 children with KCNQ2 gene variants (NM_172107) detected by whole-exome sequencing (WES) from October 2018 to November 2022 were analyzed, and the genotypic characteristics and treatment were analyzed. Results A total of 24 children (14 boys and 10 girls) with epilepsy caused by KCNQ2 gene variations were included. The age of the first seizure in these children ranged from 17 hours after birth to 5 years old. Among them, 16 children (66.7%) were younger than 6 months. According to the clinical prognosis, there were 1 case of benign familial neonatal epilepsy (BFNE), 6 cases of benign familial infantile epilepsy (BFIE), 4 cases of self-limited epilepsy syndrome that could not be classified, and 13 cases of KCNQ2-related developmental and epileptic encephalopathy (KCNQ2-DEE). The main genetic variation was missense mutation (62.5%), and 7 new KCNQ2 mutation sites were found. Among them, c.1411C>T was evaluated as pathogenic, c.602G>C, c.1031G>A, c.2159_2173del (p.720_725delinsR) was evaluated as likely pathogenic. The median follow-up time of the 24 patients was 40 months. 13 patients had varying degrees of developmental delay in KCNQ2-DEE, and the remaining 11 patients had good overall prognosis and normal cognitive development. Conclusions The age of seizures associated with KCNQ2 variation is mainly distributed in the neonatal period and early infancy. The prognosis of KCNQ2-DEE is poor. It is recommended that genetic testing should be performed as early as possible for the diagnosis of unexplained seizures in infancy.