Abstract: Ornithine transcarbamylase （OTC） deficiency，also known as hyperammonemia type Ⅱ，is the most common type of congenital urea cycle disorders.The main clinical manifestations of OTC deficient patients are hyperammonemia and neurological abnormalities.The OTC enzyme activity and the blood ammonia level at the onset determines the severity of its clinical manifestations and the prognosis.OTC deficiency may occur from infancy to adulthood. The onset of the disease may occur in the female with pathogenic variation，and it is critical in infancy，which progresses napidly with a poor prognosis and high mortality.This article mainly describes the diagnosis and treatment of OTC deficiency that occurs in childhood，in order to guide the early diagnosis and standard treatment of the disease，improve the prognosis of children，and reduce the death and disability rate

Key words: ornithine carbamytransferase deficiency, urea cycle disorders, hyperammonemia

摘要： 鸟氨酸氨甲酰转移酶（ornithine transcarbamylase，OTC）缺乏症又称为高氨血症Ⅱ型，是先天性尿素循环障碍疾病中最常见的类型。临床主要表现为高氨血症及神经系统损害，OTC活性缺失程度及发病时血氨水平决定其临床表现及预后严重程度。OTC缺乏症在新生儿至成人期均有发病，且携带致病变异的女性也可能发病，其中婴幼儿期发病者起病危重，病情进展迅速且预后差、病死率高。文章主要阐述了儿童期内发病的OTC缺乏症诊断与治疗，以期指导该病早期诊断和规范治疗，改善患儿预后，降低死亡和致残率。

关键词: 鸟氨酸氨甲酰转移酶缺乏症, 尿素循环障碍, 高氨血症