m.3303C>T突变引起线粒体心肌病一例及文献复习
m.3303C>T Mutation Caused Mitochondrial Cardiomyopathy: A Case and Literature Review

目的：报告1例由m.3303C>T突变引起MCM的患儿的临床表现以及诊断过程，以提高对该病的临床认识以及早期诊断。方法：回顾分析1例于我科确诊的MCM患儿的临床资料，通过高通量测序技术获得突变基因信息，采用Sanger法验证突变位点，最终确诊本病。结果：男性患儿6个月，发现心脏杂音就诊，行心超提示心肌肥厚，考虑心肌病。患儿入院后完善基因检测提示m.3303C>T纯质性变异，为已报道的疑似致病变异。该例患儿在治疗期间心肌呈进行性增大，心功能下降迅速，半年后死亡。结论：由m.3303C>T突变引起线粒体心肌病的患儿病情进展较迅速，如不明原因心脏增大/心肌肥厚的患儿就诊，建议完善线粒体环基因检测协助明确病因，排除线粒体心肌病可能。
Objective: A case of mitochondrial cardiomyopathy caused by the m.3303C>T mutation was reported to improve the clinical understanding and early diagnosis of the disease. Methods: Retrospective analysis of the clinical data of a child diagnosed with MCM in our department. Mutation gene information was obtained using high-throughput sequencing technology, and the mutation site was verified by the Sanger method, which ultimately confirmed the disease. Results: A six-month-old boy was found to have a heart murmur and was diagnosed with myocardial hypertrophy through echocardiography, suggesting cardiomyopathy. Genetic testing after admission indicated a m.3303C>T homoplasmic variation, which is a reported suspected pathogenic variant. During the treatment, the myocardium of the child was progressively enlarged, with the cardiac function decreasing rapidly. This child died six months later. Conclusions: Children with mitochondrial cardiomyopathy caused by the m.3303C>T mutation have rapid progression. If children present with unexplained cardiac enlargement/myocardial hypertrophy, the mitochondrial genetic examination may help us to diagnose the cause of cardiomyopathy and rule out the possibility of mitochondrial cardiomyopathy.