As an allosteric activator of CPS1, carglumic acid reactivates the genetically impaired UC and lowers systemic ammonia.20, 22, 23 In an induced hyperammonemic rat model, the flavonoid fisetin showed the ability to prevent oxidative stress, normalized blood ammonia, and increased the expression of UCD enzymes, including CPS1.24, 25 Hepatocyte or stem cell transplantation and new approaches for gene therapy have become promising treatment for CPS1D.26 This evidence concerns the gene CPS1 and carbamoyl phosphate synthetase I deficiency disease.