Sickle Cell Disease is a term for a group of hereditary blood disorders. Sickle Cell Disease is caused by abnormal hemoglobin, the protein in red blood cells that carries oxygen from the lungs to the tissues. People with sickle cell disease make hemoglobin S (Hb S) instead of the normal hemoglobin A. The red blood cells of persons with sickle cell disease don't last as long as 'normal' red blood cells. This results in chronic anemia.
Also, these red blood cells become rigid and bend, taking on a 'sickle ' or crescent shape. These odd shaped cells are not flexible enough to squeeze through small blood vessels. This may result in blood vessels being blocked. The areas of the body served by those blood vessels will then be deprived of their blood circulation. This damages tissues and organs and causes pain. Organs that can be damaged include bones, kidneys, lungs and the brain.
In the United States, sickle cell disease is found primarily in people of African ancestry. However, many other people, especially those coming from the Mediterranean, Middle East and some part of India have this disorder. The most common type of sickle cell disease is sickle cell anemia which affects more than 50,000 Americans. One in 375 African Americans is born with sickle cell anemia.