摘要目的:探讨SLC25A1基因相关性先天性肌无力综合征（CMS）的临床及遗传学特征。方法:回顾性分析2015年1月至2019年6月复旦大学附属儿科医院诊治的2例SLC25A1基因相关性CMS患儿的临床资料，并以“SLC25A1”“先天性肌无力综合征”为关键词对万方数据知识服务平台、中国期刊全文数据库（CNKI），以“SLC25A1”“congenital myasthenic syndrome”为关键词，对美国国家生物技术中心（NCBI）、生物医学文献数据库（Pubmed）建库至2020年6月收录的论文进行检索。总结SLC25A1基因相关性CMS的临床表型及基因型特点。结果:2例患儿均为男性，分别为9岁、2岁，发病年龄均在婴儿期，其共同临床表现除典型的CMS症状（波动性肌无力，包括上睑下垂、斜视、咀嚼无力、声音低弱、四肢无力）外，还具有智力障碍、发育迟缓及代谢异常（尿中2-酮戊二酸升高、乳酸升高或者2-羟基戊二酸尿症），家系全外显子测序检测发现存在SLC25A1基因复合杂合变异。文献检索到3篇英文文献共15例患儿，包括本组2例共17例纳入分析，均于2岁以内起病，9例合并轻度智力低下，1例合并发育迟缓；共发现5个SLC25A1基因变异，包括3个错义变异及1个无义变异、1个缺失变异，其中6个家系中12例患儿携带c.740G>A（R247Q）纯合变异，本组2例患儿均有c.145G>A（V49M）变异。结论:SLC25A1基因相关性CMS患儿起病早，多合并智力障碍或者发育迟缓，部分有代谢异常表现，基因型中R247Q和V49M具有重复性。

abstractsObjective:To investigate the clinical characteristics and genetic features of congenital myasthenic syndrome (CMS) related to SLC25A1 gene variant.Methods:The clinical data of two SLC25A1 gene variant related CMS patients treated at the Children′s Hospital of Fudan University between January 2015 and June 2019 were analyzed retrospectively. A literature search with “SLC25A1” and “congenital myasthenic syndrome” as key words was conducted at China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform, National Center from Biotechnology Information and Pubmed (up to June 2020). The clinical characteristics and genetic features of congenital myasthenic syndrome related to SLC25A1 gene variant were summarized.Results:Two patients were all males, aged 9 years and 2 years respectively and the onset age was in infancy. In addition to typical CMS symptoms (fatigable muscular weakness, including bilateral ptosis, strabismus, masticatory weakness, low voice and limb weakness), the two patients both had developmental delay along with metabolic abnormalities (elevated urinary 2-ketoglutarate (2-KG), elevated lactic acid levels or 2-hydroxyglutaric aciduria). Trio whole-exome sequencing (WES) revealed two novel pathogenic variants of SLC25A1(c.628C>T, p.R210X; c.145G>A, p.V49M) in case 1 and (c.145G>A, p.V49M; microdeletion) in case 2. After literature search, 15 cases in 3 English articles were found, which made up the complete case data of 17 patients (including these 2 cases). Seventeen patients had very early onset with the age of 2 years. Mild intellectual disability was recorded in 9 patients, and mild developmental delay was observed in one patient. 5 SLC25A1 gene variants (three missense, one nonsense and one microdeletion) were identified in these cases. Twelve patients from 6 pedigrees harbored one same variant (c.740G>A, p.R247Q) and two cases had the other variant (c.145G>A, p.V49M).Conclusions:Patients diagnosed with SLC25A1 related CMS have very early onset, and most of them have intellectual disability or developmental delay. Part of patients had metabolic abnormalities. The variants (c.740G>A, p.R247Q and c.145G>A, p.V49M) are recurrent.