Definition:

N-acetylglutamate synthase (NAGS) deficiency is a rare inborn error of metabolism affecting ammonia detoxification in the urea cycle. The N-acetylglutamate is the absolutely required allosteric activator of the first urea cycle enzyme carbamoylphosphate synthetase 1 (CPS1). In defects of NAGS, the urea cycle function can be severely affected resulting in fatal hyperammonemia in neonatal patients or at any later stage in life. Clinical features of NAGS deficiency include poor feeding, vomiting, altered level of consciousness, seizures, and coma.