Mitochondrial hepatopathy: Anticipated difficulties in management of fatty acid oxidation defects and urea cycle defects

Figure 1 Carnitine shuttle. CoA: Co-enzyme A; FATP: Fatty acid transport protein; OCTN2: Organic cation transporter 2; CPT: carnitine palmitoyltransferase; CACT: Carnitine acyl carnitine transporter.

Figure 2 Beta-oxidation of fatty acids. CoA: Co-enzyme A; NAD: Nicotinamide adenine dinucleotide; NADH2: Nicotinamide adenine dinucleotide (reduced); FAD: Flavin adenine dinucleotide; FADH: Flavin adenine dinucleotide (reduced).

Figure 3 Urea cycle. NAGS: N-acetyl glutamate synthase; NAG: N-acetyl glutamate; CoA: Co-enzyme A; CPS-1: Carbamoyl phosphate synthetase 1; NH3: Ammonia; HCO3: Bicarbonate; ATP: Adenine triphosphate; OTC: Ornithine transcarbamoylase; ORNT: Ornithine transporter; ASS: Argininosuccinate synthetase; ASL: Argininosuccinate lyase.

Figure 4 Approach to individual urea cycle defects. NAG: N-acetyl glutamate; CPS-1: Carbamoyl phosphate synthetase 1; OTC: Ornithine transcarbamoylase; ASS: Argininosuccinate synthetase; ASL: Argininosuccinate lyase; HHH: Hyperornithinemia-hyperammonemia-homocitrullinuria syndrome.