NAGS variants cause NAGS deficiency

N-Acetylglutamate Synthase Deficiency (NAGSD) is a rare autosomal recessive urea cycle disorder caused by a deficiency of the mitochondrial enzyme N-acetylglutamate synthase (NAGS). This enzyme is essential for activating carbamoyl phosphate synthetase I (CPS1), the first and rate-limiting enzyme in the urea cycle. Without NAGS, CPS1 is inactive, preventing the initiation of the urea cycle and leading to accumulation of ammonia (hyperammonemia) (Caldovic et al, 2002; Morizono et al, 2004; Caldovic et al, 2010; reviewed in Sancho-Vaello et al, 2016).

Summary from Reactome (R-HSA-9955693), read 2026-09-23.