Glucose-6-phosphate dehydrogenase (G6PD) deficiency (OMIM305900), an X-linked inherited disease, is the most common human enzyme deficiency. G6PD is the housekeeping gene encoding the first
key enzyme in the pentose phosphate pathway. G6PD deficient erythrocytes do not generate enough NADPH H+, which is essential for protection against oxidative stress from exogenous oxidizing agents in the blood as well as the oxygen radicals continuously generated as hemoglobin cycles between its deoxygenated and oxygenated forms. Red blood cells (RBCs) do not contain a nucleus, so the pentose phosphate pathway is their only source of NADPH. Therefore, RBCs are more susceptible to oxidative damage than any other cells [1]. The hemolytic anemia in G6PD deficiency is usually triggered by medications or fava beans.