The consequent accumulation of methylmalonic-CoA results in the competitive inhibition of N-acetylglutamate synthase and carbamoyl phosphate synthase 1 (CPS 1), an enzyme involved in the first and rate-limiting step of the urea cycle, causing hyperammonemia (Alfadhel et al., 2021). The gene discussed is CPS1; the disease is Hyperammonemia.