Figure 5: An approach to diagnosis of hyperammonemia in older children OA: organic acidurias, FAO: fatty acid oxidation defects, PC: pyruvate carboxylase deficiency, PDH: pyruvate dehydrogenase deficiency, ASA: argininosuccinic acid, AS: argininosuccinic aciduria, NAGS: N-acetylglutamate synthetase deficiency, CPS I: carbamoyl phosphate synthetase I deficiency, OTC: ornithine transcarbamoylase deficiency, HHH: hyperornithinemia hyperammonemia homocitrullinuria syndrome, LPI: lysinuric protein intolerance