[Neonate-onset ornithine transcarbamylase deficiency]

Abstract

The male neonate in this case study was admitted to the hospital at 15 hours of age due to respiratory distress for 15 hours and poor response for 3 hours after resuscitation from asphyxia. The neonate was highly unresponsive, with central respiratory failure and seizures. Serum ammonia was elevated (>1 000 μmol/L). Blood tandem mass spectrometry revealed a significant decrease in citrulline. Rapid familial whole genome sequencing revealed OTC gene mutations inherited from the mother. Continuous hemodialysis filtration and other treatments were given. Neurological assessment was performed by cranial magnetic resonance imaging and electroencephalogram. The neonate was diagnosed with ornithine transcarbamylase deficiency combined with brain injury. He died at 6 days of age after withdrawing care. This article focuses on the differential diagnosis of neonatal hyperammonemia and introduces the multidisciplinary management of inborn error of metabolism.

Keywords: Central respiratory failure; Hyperammonemia; Neonate; Ornithine transcarbamylase deficiency; Seizure.

图1. 患儿及其父母基因变异Sanger测序结果 患儿为OTC基因变异:NM_000531.6(OTC):c.275G>A(p.Arg92Gln)，患儿母亲存在c.275G>A杂合突变，患儿父亲无突变。红色圈内所指为基因突变所在碱基位置。

图2. 患儿头颅磁共振成像 双侧脑干及丘脑见弥散加权显像信号异常（箭头所示）。

图3. 高氨血症鉴别诊断及尿素循环

图4. 患儿诊疗经过时间轴 ［OTCD］鸟氨酸氨甲酰基转移酶缺乏症；［WGS］全基因组测序；［CVVHDF］持续静脉-静脉血液透析滤过。