The LMVR has ongoing in vitro studies to characterize the effects of hemoglobin mutations and erythrocyte polymorphisms on the pathogenesis of Plasmodium falciparum, the agent of the most deadly malaria in humans. G6PD deficiency, hemoglobinopathies such as HbS, HbC, and HbE, and the thalassemias are thought to have evolved as protective traits against malaria in endemic areas of the world. However, the mechanisms by which these mutations exert their protective influence are largely unknown. Culturing P. falciparum in erythrocytes carrying protective traits will allow researchers in LMVR to characterize the cellular and molecular bases of protection using in vitro methods such as growth analyses and electron microscopy. To this effect, patients with known or suspected erythrocyte variants will be recruited in addition to normal controls.