Sickle cell disease is a blood disorder that is inherited from both parents. This disorder is more common in certain ethnic groups, such as African Americans, Arabs, Greeks, Italians, Latin and Native Americans. Normal red blood cells are very flexible and are circular in shape, resembling a doughnut. Their flexibility and shape allow them to travel freely through small blood vessels called capillaries. In persons with sickle cell disease, the red blood cells become crescent or sickle-shaped and also become inflexible. The abnormal cells stick inside the capillaries, blocking blood flow to vital organs. Persons with sickle cell anemia can have symptoms such as yellow-appearing eyes and skin, pale skin, delayed growth, bone and joint pain, increased risk for infections, development of leg ulcers, eye damage, anemia and damage to the organs affected by the obstruction.