While a response to carbamylglutamate aids in the diagnosis, it is not in itself diagnostic of NAGS deficiency, as carbamylglutamate has been shown to be effective in some cases of other inherited metabolic disorders by augmenting ureagenesis and decreasing plasma ammonia, including CPS1 deficiency, ornithine transcarbamylase (OTC) deficiency, citrullinemia type I (argininosuccinic acid synthetase deficiency), methylmalonic acidemia (MMA), propionic acidemia (PA), isovaleric acidemia (IVA), carbonic anhydrase VA (CAVA) deficiency, and multiple acyl-CoA dehydrogenase deficiency (MADD). This evidence concerns the gene CPS1 and isovaleric acidemia.