Metabolic Liver Disease

Abstract

This chapter willdealwithsomeofthemorecommon inborn errors of metabolism that lead to hepatic dysfunction. This includes three inborn errors of carbohydrate metabolism: Galactosemia, hereditary fructose intolerance, and glycogen storage disease types I, III, and IV and VI. Tyrosinemia, a disorder of amino acid metabolism will also be reviewed. Galactosemia Galactose is the end product of hydrolysis of lactose. Galactosemia is a rare inherited defect in galactose metabolism transmittedbyautosomalrecessiveinheritance.Threedistinct disorders of galactose metabolism and several variant forms have been identified. These disorders are expressed as a cellular deficiency of one of the three enzymes in the metabolic pathway through which galactose is converted to glucose: galactose-1-phosphate uridyl transferase, galactokinase, and uridine diphosphate (UDP) galactose-4epimerase. Each enzymatic defect results in a distinctive clinical presentation. Thus, the disease is now classified in terms of transferase deficiency Galactosemia, galactokinase deficiency Galactosemia, and epimerase deficiency Galactosemia.