Late-Onset Ornithine Transcarbamylase Deficiency: A Case Report of a Female Pediatric Patient and Literature Review

鸟氨酸氨甲酰基转移酶缺乏症(Ornithine Transcarbamylase Deficiency, OTCD)是尿素循环障碍中最常见的X连锁隐性遗传病。该病因高氨血症引发进行性脑损伤及肝功能异常，临床表现存在显著个体差异。本文报告1例2岁6个月女性迟发型患儿，以反复呕吐、性格改变及肝功能异常为特征表现，经血浆氨检测、串联质谱、基因测序确诊为OTCD。通过低蛋白饮食、降氨治疗及后续肝移植干预，患儿病情得到有效控制。本病例提示，对于不明原因呕吐伴高氨血症的婴幼儿，需高度警惕尿素循环障碍可能，早期开展血氨筛查及基因检测有助于及时诊断。本研究通过病例分析结合文献复习，为临床识别及管理OTCD提供参考。Ornithine Transcarbamylase Deficiency (OTCD), the most prevalent X-linked recessive disorder in urea cycle defects, induces progressive neurological damage and hepatic dysfunction through hyperammonemia, with marked individual variations in clinical manifestations. This study presents a 2-year-and-6-month-old female patient with late-onset OTCD, characterized by recurrent vomiting, personality changes, and abnormal liver function. Diagnosis was confirmed through plasma ammonia measurement, tandem mass spectrometry, and genetic sequencing. Effective management was achieved via low-protein diet, ammonia-lowering therapy, and subsequent liver transplantation. This case underscores the necessity of suspecting urea cycle disorders in infants with unexplained vomiting accompanied by hyperammonemia, emphasizing that early plasma ammonia screening and genetic testing are crucial for timely diagnosis. Through comprehensive case analysis and literature review, this study provides clinical insights for the identification and management of OTCD.