目的 提高对线粒体复合物 I 缺乏症20型（MC 1 DN 20）临床表型及基因型的认识。方法 回顾分析1例 MC 1 DN 20患儿的临床资料并复习相关文献。结果 男性患儿，出生后即表现为精神及反应差，顽固性代谢性酸中毒及高 乳酸血症和肝脏增大。全外显子基因测序发现ACAD 9基因变异，c.1278+1G>A为母源性剪切变异，c.895 A>T 为父源 性错义变异；线粒体基因二代测序及MLPA未发现受检者有临床意义的线粒体基因变异及大片段变异。结论 发现导致 MC 1 DN 20的新的线粒体核基因ACAD9的c. 1278 + 1 G>A剪切变异和c. 895 A>T错义变异 。

Objective To improve the understanding of the clinical phenotype and genotype of mitochondrial complex I deficiency nuclear type 20 (MC 1 DN 20 ). Methods The clinical data of mitochondrial complex I deficiency nuclear type 20 in a child was analyzed retrospectively and the related literature was reviewed. Results A boy was born with poor spirit and reaction, refractory metabolic acidosis, hyperlactacidemia and liver enlargement. A maternal splicing mutation of c.1278 +1 G>A and a paternal missense mutation of c. 895 A>T were found in ACAD 9 gene by whole exome gene sequencing. No significant mitochondrial gene variation and large fragment variation was found in the second-generation sequencing of mitochondrial gene and multiplex ligation-dependent probe amplification. Conclusion It was found that the c.1278 + 1 G>A splicing mutation and the c.895 A>T missense mutation of the new mitochondrial nuclear gene ACAD9 leads to MC1 DN 20 .