Urea cycle disorder (UCD) is one of inborn error diseases.Citrullinemia is the most common disease (1/57000) among them, followed by argininosuccinic acidemia (ASA) (1/70000).

• 摘要尿素循环功能障碍为先天性代谢缺陷的一类，瓜胺酸血症为最常见的一种，发生机率为1/57000；