A few people with sickle trait have problems at high altitudes, where there is less oxygen. The important issue for people with sickle trait is that, if two persons with sickle trait marry, there is a one in four chance of a child being born with sickle cell anemia. This clotting clogs blood vessels and thereby interferes with the flow of blood, depriving the body tissues of oxygen and causing a painful attack called a crisis. A sickle cell crisis may last several days. Sickle cell anemia may injure almost all parts of the body, especially the bones, central nervous system, liver, lungs, and the spleen.
Some victims suffer blindness, convulsions, paralysis, or loss of speech.
With appropriate medical care, most people with sickle cell anemia live to middle age. Since then, researchers have found that several chemical compounds, including urea, carbamyl phosphate, and sodium cyanate, can reverse the sickling process. However, these drugs can have serious side effects and, under some testing procedures, have not proved as effective as researchers originally hoped. Researchers are experimenting with these and other drugs in an effort to find a safe, effective treatment. Currently, blood transfusions are usually given only when the anemia is severe enough to cause serious illness.