目的　分析由脱氧鸟苷激酶（DGUOK）基因突变导致的线粒体DNA缺失综合征（MDS）的临床特征、基因突 变特点。方法　回顾分析1例经二代测序确诊MDS患儿的临床资料。结果　36天男性婴儿，因低血糖、腹胀就诊，有肝功 能异常、低血糖、乳酸增高。二代基因检测发现患儿DGUOK基因存在2个新发现突变，c.169dupT及c.630dupG，父母各 携带1个突变，均为移码突变；产生截短蛋白。应用SWISS-MODE进行蛋白结构预测，对DGUOK结构造成影响，均未有 文献报道。患儿住院治疗无好转，死亡。结论　DGUOK基因突变导致的MDS病情严重，预后极差。早期基因检测有助于 诊断及遗传咨询。

Objective　To analyze the clinical features and genetic change of mitochondrial DNA deletion syndrome (MDS) caused by deoxyguanosine kinase (DGUOK) gene mutation. Methods　The clinical data of a case diagnosed with MDS by next generation sequencing of a boy were retrospectively analyzed. Results　A 36-day-old boy presented with hypoglycemia, abdominal distension, abnormal liver function, low blood glucose and high lactic acid. Gene testing identified two novel compound heterozygous mutations c.169dupT and c.630dupG in DGUOK, both of which were frameshift mutations resulted in truncated protein. Each parent was a heterozygous mutation carrier. SWISS-MODE predicted the damage effect on the structure of DGUOK. After 16 days of hospitalization, the boy was discharged from hospital without any improvement and then died. Conclusion　The MDS caused by DGUOK gene mutation is very serious with poor prognosis. It is necessary to screen genes early when abnormal liver function, hypoglycemia, hyperlactacidemia and other symptoms occur in newborns and infants. Early diagnosis is helpful for genetic counseling and guidance for prenatal diagnosis of the next pregnancy.