线粒体呼吸链复合物Ⅰ缺陷导致幼儿肝内胆汁淤积症

线粒体呼吸链复合物缺陷是导致儿童线粒体病的主要原因。本文就1例线粒体呼吸链复合物Ⅰ缺陷导致的幼儿胆汁淤积症患者的临床经过、生化特点、线粒体呼吸链复合物活性分析及基因突变进行回顾性研究。患儿，男，自1岁1个月起腹泻，体重下降，伴无力、进行性黄疸、肝损害。经多种检查、尿液有机酸分析及血液氨基酸、酯酰肉碱谱分析未见特异性改变。外周血白细胞线粒体呼吸链复合物Ⅰ活性降低，线粒体基因分析发现患儿及其母亲tRNA 5821G>A突变，证实患儿存在线粒体呼吸链复合物Ⅰ缺陷。患儿疾病进展迅速，治疗无效，于1岁5个月时夭折。复合物Ⅰ缺陷是线粒体呼吸链缺陷中最常见的类型，本研究首次诊断了1例线粒体呼吸链复合物Ⅰ缺陷所导致的中国儿童患者，其临床表现为胆汁淤积症。线粒体肝病是导致儿童代谢性肝病的主要原因之一，生化分析、线粒体呼吸链复合物活性测定及基因分析是病因诊断的关键。

Intrahepatic cholestasis due to mitochondrial respiratory chain complex I deficiency in a Chinese boy

Mitochondrial respiratory chain deficiency is a common cause of mitochondrial disease in children. This study aimed to review the clinical, enzymatic and genetic characteristics of a Chinese boy with progressive intrahepatic cholestasis due to mitochondrial respiratory chain complex I deficiency. The boy developed diarrhea from the age of 13 months, followed by progressive body weight loss, jaundice and weakness. His urine organic acids, blood amino acids and acylcarnitines profiles were normal. Mitochondrial respiratory chain complexes I to V activities in peripheral leukocytes were measured using spectrophotometric assay. Complex I activity was reduced. 5821G>A mutation was indentified by gene sequencing on tRNA-cys of mitochondrial gene in the patient and his mother. Vitamin supplements, liver protection, antibiotics and plasma infusion were not effective in the patient. Unfortunately, the boy died at the age of 17 months. Mitochondrial respiratory chain complex I deficiency is the most common mitochondrial respiratory chain disorder. This was the first case of intrahepatic cholestasis due to complex I deficiency confirmed by mitochondrial respiratory chain enzyme activity assay and gene analysis in China. It was concluded that mitochondrial hepatopathy is one of major causes of metabolic hepatopathy. Biochemical assay, mitochondrial respiratory chain complex activities assay and genetic analysis are crucial for the etiological diagnosis of metabolic hepatopathy.