目的　探讨高鸟氨酸血症-高氨血症-高同型瓜氨酸尿症（HHH综合征）的临床及基因突变特点。方法　回顾 分析1例HHH综合征患儿的临床资料，并复习文献。结果　患儿，女， 2岁2个月，平素厌食高蛋白食物。生后反应弱，独 走后出现共济失调，感染后加重。实验室检查示高氨血症、转氨酶升高及凝血异常。头颅MRI示半卵圆中心白质容积减少。 基因检测示患儿携带SLC25A15基因c.190T>C（p.Y64H）及c.278G>A（p.R93Q）复合杂合突变，分别来自表型正常的父母。 结论　HHH综合征临床表现以神经系统及肝脏受累为主要，需与其他尿素循环障碍及肝脏疾病相鉴别。

　Objective　To explore the clinical and gene mutation characteristics of hyperornithinemia-hyperammoniahyperhomocysteinuria (HHH syndrome). Methods　The clinical data of HHH syndrome in a child were retrospectively analyzed and the literature was reviewed. Results　A girl, aged 2 years and 2 months, had an aversion to high-protein foods. The child's reaction was weak after birth, and the ataxia occurred when she walked alone and was aggravated after infection. Laboratory tests showed hyperammonia, elevated transaminase and abnormal coagulation. Head MRI showed decreased white matter volume in the semioval center. The genetic test showed that the child carried compound heterozygous mutations of SLC25A15 gene, c.190T>C (p.Y64H) and c.278G>A (p.R93Q), which were derived from her parents with normal phenotype. Conclusion　The main clinical manifestations of HHH syndrome are involvement of nervous system and liver, and required to be differentiated from other urea circulatory disorders and liver diseases. The newly discovered SLC25A15 gene locus mutation may be the pathogenic site of HHH syndrome.