Disorders of Carbohydrate Metabolism

Abstract

This chapter discusses disorders that directly affect the metabolism of mono-, oligo-, and polysaccharides. In metabolic disorders of complex glycoproteins and glycolipids, the breakdown of not only carbohydrates but also of other catabolites is impaired. Under the monosaccharidose category, all conditions accompanied by alterations in glucose metabolism are considered, which is justified by the central position of glucose in energy metabolism. Mostly, defects in the enzymes that control glucose catabolism are observed. This chapter further discusses disorders related to respiratory chain. As a result of disturbances on their predominantly lysosomal breakdown, oligosaccharides accumulate and are either excreted in the urine in large quantities or deposited in various organs. For this reason, the corresponding disease entities are called glycoproteinoses. The homopolysaccharide, glycogen forms the reserve carbohydrate in the energy metabolism of vertebrates. It is of paramount importance in the regulation of blood sugar levels. The glycogenoses are a group of metabolic disorders characterized by abnormal storage of glycogen in various organs or by formation of abnormal glycogens. They form a group of genetically determined metabolic disorders, and their classification is based on the underlying enzyme defect.