Sickle cell trait occurred as a natural mutation of the hemoglobin gene. Sickle trait serves as a protective mechanism against malaria. Malaria is a deadly disease found in countries along the equator. People with sickle cell trait are protected from malaria while those with sickle cell anemia and normal hemoglobin are susceptible to it. Over (he years people with sickle trait migrated to other continents.

Sickle cell disease is seen predominantly in the black population but is also seen in people of other ethnic groups. These ethnic groups include individuals from parts of the Middle East, Central India, and countries bordering the Mediterranean Sea, especially Italy and Greece.

Origin and Distribution of Sickle Cell Disease, Genetics, Sickle Red Blood Cells, Infections ,Splenic Sequestration, Pain, Chest Syndrome, Aplastic Crisis, Strokes, Gall Stones and Jaundice, Growth and Development, Retinopathy, Priapism