迟发型先天性鸟氨酸氨甲酰基转移酶缺陷病临床及家系分析

Clinical and pedigree analysis of late onset congenital ornithine transcarbamylase deficiency in a child

目的总结分析1例先天性鸟氨酸氨甲酰基转移酶缺乏症（OTCD）患儿的临床特征及其家系特点，提高临床医师对该病的认识。方法对本院确诊的1例OTCD患儿临床特点进行分析。采取外周血利用直接测序技术对患儿及其父母、姐姐鸟氨酸氨甲酰基转移酶（OTC）基因的10个外显子及其相邻9个内含子进行基因分析。并对患儿二、三级亲属发病情况进行调查。结果患儿于出生后6个月起病，临床表现为反复发作性呕吐、精神差、血氨增高、肝功能异常。一同胞哥哥因同样表现于生后6个月夭折，一同胞姐姐健康。基因检测显示患儿携带IVS1—2A〉G内含子突变，患儿母亲及姐姐为携带者，父亲未发现基因突变。，患儿外祖父母、舅舅及其子女均健康。结论OTCD是一种先天遗传性疾病，也是高氨血症常见的原因之一，临床表现多样而易误诊。OTC基因IVS1—2A〉G突变是导致本例患儿发病的原因，本家系发病情况提示该患儿为x连锁隐性遗传疾病。

Objective To raise the awareness of congenital ornithine transcarbamylase deficiency （OTCD） by analyzing the clinical features and the family pedigree in a child with OTCD. Methods Clinical characteristics were analyzed in a child with OTCD. The genetic analysis was performed in ten exons and nine intron-exon boundaries in the ornithine transcarbamylase （OTC） gene of the case and his family by direct sequencing of PCR-DNA from peripheral blood. Family history including his grandparents and uncle was registered. Results The onset age of the case was 6 months old, the clinical picture was characterized by recurrent episodes of vomiting, low spirits, hyperammonemia, and abnormal liver function. His brother died of the similar performance at 6 months old. His sister was healthy. IVS1-2A〉G intron mutation of OTC gene was found in the case, while his mother and sister were the carriers and his father revealed no mutation. His maternal grandparents and his unele＇s family were healthy. Conclusion OTCD is a kimi of congenital genetic disease, and is one of the main causes of hyperammonemia. Misdiagnosis is very common because clinical symptoms of this disease are variable. [VS1-2A〉G mutation in OTC gene is the pathogeny of this case. The family genealogy indicates that this case is a kind of X-linked recessive hereditary disease.