hematology and oncology
Glycolytic Pathway Defects
Introduction
Glycolytic pathway defects are autosomal recessive red blood cell metabolic disorders that cause hemolytic anemia. (See also Overview of Hemolytic Anemia .) The glycolytic pathway is one of the body's important metabolic pathways. It involves a sequence of enzymatic reactions that break down glucose (glycolysis) into pyruvate, creating the energy sourcesadenosinetriphosphate (ATP) andnicotinamideadenine dinucleotide (NADH). Various inherited defects in enzymes of the pathway may occur. Themost commondefect is Pyruvate kinase deficiency Other defects that cause hemolytic anemia include deficiencies of Erythrocyte hexokinase Glucose phosphate isomerase Phosphofructokinase In all of these pathway defects, hemolytic anemia occurs only in patients who are homozygous for the mutation. The exact mechanism of hemolysis is unknown. Symptoms are related to the degree of anemia and may include jaundice and splenomegaly. Spherocytes are absent, but small numbers of irregularly shaped cells (echinocytes) may be present. In general, assays of ATP and diphosphoglycerate help identify any metabolic defect and localize the defective sites for further analysis. 