PNPO and hyperinsulinemic hypoglycemia, familial, 4: The occurrence of hepatotoxicity in the transplanted liver indicates that the hepatotoxicity of PLP in patients with PNPO deficiency is not primarily the result of abnormal PLP metabolism due to hepatic PNPO deficiency and is consistent with other reports of PLP associated hepatotoxicity occurring in people without PNPO deficiency [14].