Yang Yan-ling, Sun Fang, Qian Ning, Song Jin-qing, Wang Shuang, Chang Xing-zhi, Yang Hong-yun, Wang Shu-qin, Li Long, Zhang Yue-hua, Bao Xin-hua, Li Ming, Qi Yu, Qin Jiong, Wu Xi-ru
Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
Zhonghua Er Ke Za Zhi. 2005 May;43(5):331-4.
To investigate the incidences of urea cycle defects (UCDs) in the patients with hyperammonemia and study their etiology, clinical and laboratory features.
In the past 7 years, 26 cases (10.2%) of UCDs were detected from 254 patients with hyperammonemia. The etiological diagnoses were made by blood amino acids analysis, urinary organic acid analysis and blood acylcarnitine profile analysis. Three patients with citrullinemia type II were further confirmed by liver pathological analysis and gene diagnosis.
Among 26 cases with UCDs, 15 had ornithine transcarbamylase (OTC) deficiency, 5 had citrullinemia type I, 3 had citrullinemia type II and 3 patients had arginemia. The age of onset of the patients ranged from 3 days to 13 years. Three cases (11.5%) developed hyperammonemic encephalopathy during neonatal period. Thirteen (50.0%), 7 (26.9%) and 3 (11.5%) cases developed clinical symptoms at the age of 1 to 12 months, 1 to 3 years and 6 to 13 years, respectively. Positive family history was found in 11 cases (42.3%). Among 26 patients with UCDs, 9 (34.6%) were hospitalized with the complains of seizures, psychomotor retardation, vomiting and unconsciousness, 8 (30.8%) with recurrent vomiting, headache and coma, 6 due to liver dysfunction. Intrahepatic cholestatic jaundice was found in 3 patients with citrullinemia type II. Blood ammonia ranged from 58 to 259 micromol/L on their first visit to our hospital. Twenty cases (76.9%) had liver dysfunction, 4 patients (15.4%) were diagnosed postmortem. Twenty-one patients got treatment and were followed up. Among them, 7 cases died of hyperammonemic encephalopathy or upper alimentary tract bleeding. Clinical improvement was observed in 14 cases. A boy with OTC deficiency who received a partial liver transplant from his mother showed normal general condition for two years.
UCDs are the most frequent causes of congenital hyperammonemia. In this study, 26 patients (10.2%) with UCDs were identified from 254 patients with hyperammonemia resulting in encephalopathy and liver dysfunction. Early diagnosis and treatment can contribute a lot to improve the prognosis of the patients. Blood ammonia assay and further etiological analysis should be considered in the differential diagnosis of neurological and hepatic abnormality.
探讨高氨血症患者中尿素循环障碍（UCDs）的发生率，并研究其病因、临床及实验室特征。
在过去7年中，从254例高氨血症患者中检测出26例（10.2%）UCDs患者。通过血氨基酸分析、尿有机酸分析及血酰基肉碱谱分析进行病因诊断。3例Ⅱ型瓜氨酸血症患者通过肝脏病理分析和基因诊断进一步确诊。
26例UCDs患者中，15例为鸟氨酸转氨甲酰酶（OTC）缺乏，5例为Ⅰ型瓜氨酸血症，3例为Ⅱ型瓜氨酸血症，3例为精氨酸血症。患者发病年龄为3天至13岁。3例（11.5%）在新生儿期发生高氨血症性脑病。13例（50.0%）、7例（26.9%）和3例（11.5%）患者分别在1至12个月、1至3岁和6至13岁出现临床症状。11例（42.3%）有阳性家族史。26例UCDs患者中，9例（34.6%）因惊厥、精神运动发育迟缓、呕吐和昏迷入院，8例（30.8%）因反复呕吐、头痛和昏迷入院，6例因肝功能障碍入院。3例Ⅱ型瓜氨酸血症患者出现肝内胆汁淤积性黄疸。首次来我院就诊时血氨浓度为58至259 μmol/L。20例（76.9%）有肝功能障碍，4例（15.4%）为尸检确诊。21例患者接受治疗并进行随访。其中7例死于高氨血症性脑病或上消化道出血。14例临床症状改善。1例OTC缺乏男孩接受其母亲的部分肝移植后，两年内一般情况正常。
UCDs是先天性高氨血症最常见的病因。本研究中，从254例高氨血症患者中确诊26例（10.2%）UCDs患者，导致脑病和肝功能障碍。早期诊断和治疗对改善患者预后有很大帮助。在神经和肝脏异常的鉴别诊断中应考虑血氨检测及进一步的病因分析。
