[Hemolytic anemia due to the dysfunction of the protection against oxidative attack]

The most important products of the hexose monophosphate pathway is reduced nicotinamide adenine dinucleotide phosphate (NADPH). Reduced glutathione (GSH) maintained by the reduction of oxidized glutathione (GSSG) using NADPH as a cofactor, is a major reducing agent in the red cell and the ultimate source of protection against oxidative attack. In the syndromes associated with dysfunction of the hexose monophosphate pathway and glutathione synthesis and metabolism, oxidative denaturation of hemoglobin is the major contributor to the hemolytic process. Glucose-6-phosphate dehydrogenase (G6PD) plays a key role in the generation of NADPH. G6PD deficiency is the most common metabolic disorder, and it is associated with chronic hemolytic anemia and/or drug- or infection-induced acute hemolytic attack. It is estimated that 400 million people are affected worldwide. The mutations responsible for 101 variants have been determined. Some of them have polymorphic frequencies in different populations. Most variants are produced by one or two nucleotide substitutions. Molecular studies have disclosed that most of the class 1 G6PD variants associated with chronic hemolysis have the mutations surrounding the site of dimer formation.