Leader The molecular basis of disorders of red cell enzymes

The mature red cell has no nucleus or organelles and therefore cannot synthesise protein or lipids. It is totally dependent on glycolysis to convert glucose into an energy source. Glucose is phosphorylated by hexokinase to glucose-6-phosphate. This is the substrate for anaerobic glycolysis which proceeds through the Embden-Meyerhof pathway to pyruvate with production of ATP (fig 1). Some of the glucose-6-phosphate may also be processed by oxidative glycolysis in the pentose phosphate pathway (fig 2). Around 20 enzymes facilitate these two major pathways and deficiency of any of these enzymes may cause haemolytic anaemia. The incidence of deficiency varies from over 400 million cases worldwide in glucose-6-phosphate dehydrogenase (G6PD) deficiency to single case report in some of the other enzymes. I shall discuss the molecular basis of some of these enzyme deficiencies in this review.