NAGS and urea cycle disorder: The most common UCD is an X-linked deficiency in ornithine transcarbamylase (OTC), whereas autosomally recessive inherited deficiency in N-acetyl glutamate synthase (NAGS), carbamoyl synthase (CPS1), argininosuccinate synthetase (ASS), argininosuccinate lyase (ASL), or arginase 1 (AR1) are less frequent [4].