Table 1.

Metabolic disorders can be classified into the following three broad groups based on a liver transplantation perspective

Category	Description	Examples
A	Disorders with enzyme defect only in the liver and LT is done predominantly for ESLD and its related complications	Tyrosinemia (HT-1); A1AT deficiency; Galactosemia (type 1 Galactosemia); WD; Hereditary fructosemia; GSD 3 and 4; CDG; LSD
B	Disorders with enzyme defects limited to the liver. These patients rarely have ESLD; LT is performed for extrahepatic organ involvement	UCD; Porphyrias; GSD type 1: PH, FH; Crigler-Najjar syndrome
C	Disorders having enzyme defect in the liver and extrahepatic tissue and LT only partially corrects underlying metabolic disease and alleviates symptoms of extrahepatic organ involvement	MMA; PA; MSUD; MH

ESLD: End-stage liver disease; HT-1: Hereditary tyrosinemia type 1; A1AT: Alpha-1 antitrypsin; WD: Wilson disease; GSD: Glycogen storage disorder; CDG: Congenital disorder of glycosylation; LSD: Lysosomal storage disorders; UCD: Urea cycle disorders; PH: Primary hyperoxaluria; FH: Familial hypercholesterolemia; LT: Liver transplantation; MMA: Methyl malonic acidemia; PA: Propionic acidemia; MSUD: Maple syrup urine Disease; MH: Mitochondrial hepatopathies.