Doctors noticed that patients who had sickle cell anemia, a serious hereditary blood disease, were more likely to survive malaria, a disease which kills some 1.2 million people every year.

In sickle cell disease (SCD), the hemoglobin is abnormal and distorts the RBCs into a sickle shape. This shape causes the RBCs to clump together, thus impairing blood flow and oxygen delivery ...