Detection of CPS1 gene mutation in a neonate with carbamoyl phosphate synthetase I deficiency

Objective To explore the genetic basis for a neonate featuring hyperammonemia. Methods The patient was examined and tested by tandem mass spectrometry and next generation sequencing (NGS). Suspected mutations were confirmed by Sanger sequencing of the proband and her parents. Potential impact of the mutation was predicted with SIFT, PolyPhen-2 and MutationTaste software. Results Plasma ammonia and alanine were significantly increased in the proband, while serum citrulline was decreased. The neonate was found to harbor compound heterozygous mutations of the CPS1 gene [c.1631C>T (p.T544M) and c. 1981G>T (p.G661C)], which were respectively inherited from her father and mother. Conclusion The carbamoyl phosphate synthetase Ⅰ deficiency of the proband can probably be attributed to the mutations of the CPS1 gene. Above finding has expanded the spectrum of CPS1 mutations in association with carbamoyl phosphate synthetase Ⅰ deficiency. Key words: Carbamoyl phosphate synthetase Ⅰ deficiency; CPS1 gene; Next generation sequencing