Most common genentic enzyme defect in urea cycle is

OTC combines carbamyl phosphate with ornithine to make citrulline which is subsequently processed tourea (see: cycle diagram). Along with CPSI and NAGS deficiency, OTCdeficiency is the most severe of theurea cycle disorders. Patients with complete OTC deficiency rapidly develop hyperammonemia in the newborn period Ref-Harpers illustrated biochemistry 30/e p583