目的 探讨NADH脱氢酶1（ND1）基因m.3688G>A变异导致线粒体脑肌病Leigh病的临床特征。方法 回 顾分析1例由ND 1基因m. 3688 G>A变异导致Leigh病患儿的临床资料。结果 1岁3个月男性患儿，以表情淡漠为首发症 状，伴有精神运动发育迟滞。头颅MRI示双侧基底节、丘脑、大脑脚以及大脑皮质区多发异常信号影，病灶大致呈对称分布。 基因检测在ND1上发现一个意义未明的线粒体碱基变异m.3688G>A。结合临床特征及文献复习，患儿确诊为新发基因变 异的Leigh病。文献复习显示，mtDNA变异数量是决定临床表型的关键因素。结论 线粒体基因检测技术是诊断线粒体疾 病的重要手段。

Objective To explore the clinical features of Leigh disease caused by the mutation of m. 3688 G>A in NADH dehydrogenase 1 (ND 1) gene. Methods The clinical data of a child with Leigh disease caused by the mutation of m. 3688 G>A in ND1 gene were analyzed retrospectively. Results A 1 -year- and 3 -month-old boy presented with apathy as the first symptom, accompanied by psychomotor development retardation. Head MRI showed multiple abnormal signal shadows in the bilateral basal ganglia, thalamus, cerebral peduncle and cerebral cortex, and the lesions were roughly symmetrically distributed. An unexplained mitochondrial base mutation of m. 3688 G>A was found in ND 1 by gene test. Combined with clinical features and literature review, the child was diagnosed with Leigh disease with a new genetic variant. Through literature review, it was found that the number of mtDNA variants was a key factor in determining the clinical phenotype. Conclusion Mitochondrial gene detection technology is an important means to diagnose mitochondrial diseases.