Abstract
Carbamoyl phosphate synthetase 1 (CPS1) deficiency is an autosomal recessive urea cycle disorder which causes hyperammonemia. CPS1 is the first enzyme step in the urea cycle and almost patients present their symptoms during neonatal period. We report a case of CPS1 deficiency in a boy who developed symptoms including lethargy and seizure at 3 days of age. The ammonia level was up to $2,325{\mu}mol/L$, sodium benzoate (250 mg/kg/d) and high calories of both dextrose and lipid was promptly administered. Central access by experienced pediatric surgeon and emergent continuous hemodialysis by pediatric nephrologist was performed within 3 hours and ammonia was less than $100{\mu}mol/L$ at 5 days of age. Currently, he has showed excellent response to treatments including scavenging drugs and a low-protein diet. Despite of diffuse increasing signal intensity on cerebral white matters and basal ganglia on brain MRI, his development and weight gain were good at the last follow-up at 11 months of age. Molecular assay of the CPS1 gene demonstrated that patient had compound heterozygous for c.1529del ($p.Gly510Alafs^*5$) in exon 14 and c.3142-1G>C (IVS25(-1)G>C) in intron 25 and exon 26 boundary. The splicing mutation was novel mutation and inherited from patient's mother. Here, we report a neonatal lethal type CPS1 deficiency patient having novel mutation.
Carbamoyl phosphate synthetase 1 (CPS1) 결핍은 상염색체 열성 유전을 하는 매우 드문 유전질환으로, 요소 회로의 첫 번째 효소인 carbamoyl phosphate synthetase의 결핍에 의해 고암모니아혈증을 유발한다. CPS1 결핍은 신생아시기부터 성인까지 다양한 시기에 고암모니아혈증이 발현될 수 있으나 대부분 신생아 시기의 치명적인 고암모니아혈증으로 발현하여 예후가 불량하며 응급 투석 및 집중 치료가 필요하다. 본 증례는 드문 유전 질환인 CPS1 결핍 신생아에서 새로운 CPS1 유전자의 돌연변이를 발견하였고 조직적인 팀 접근을 통해 심각한 고암모니아혈증에 대한 신속한 투석 및 집중 치료를 시행하여 심한 뇌 병변 및 사망을 예방하고 양호한 경과를 보였음을 보고하는 바이다.
