N-carbamyl-L-glutamate,  also called carbamylglutamate or carglumic acid is a deacylase-resistant NAG analogue that is taken up enterally and replaces NAG in the activation of CPS1, thus being the definitive therapy for NAGSD[131-133]. The gene discussed is CPS1; the disease is hyperammonemia due to N-acetylglutamate synthase deficiency.