Disorders of Carbohydrate Metabolism
© 2014 Elsevier Inc. All rights reserved.Inborn errors of carbohydrate metabolism covered in this chapter include disaccharidase deficiencies, disorders of monosaccharide metabolism, glycogen storage diseases, and gluconeogenic disorders. This chapter focuses mainly on clinical aspects, genetics and current treatments for these disorders.The defective digestion of dietary disaccharides starch, lactose and sucrose is due to deficiencies of congenital lactase, adult-type lactase, or sucrase-isomaltase. Disorders of monosaccharide metabolism include defects in transport (glucose-galactose malabsorption), enzymes of galactose metabolism (galactokinase, galactose-1-phosphate uridyl transferase, and uridine diphosphate galactose-4-epimerase deficiency), enzymes of fructose metabolism (liver fructose-1-phosphate aldolase), and dehydrogenases of pentose metabolism (fructose-6-phosphate and glucose-6-phosphate). To date, there are over 12 glycogenoses, or glycogen metabolism disorders, that have been cataloged. Glycogen storage diseases (GSD), a major category of glycogenoses, are categorized by the type of tissue involved: liver, muscle, and/or cardiac. Gluconeogenic disorders entail deficiencies of fructose-1,6-diphosphatase, pyruvate carboxylase, phosphoenolpyruvate carboxykinase, and pyruvate dehydrogenase complex.
