How common is sickle cell anemia?
Originally Published: February 8, 2002
Dear Alice,What percentage of African Americans in the U.S. are diagnosed with Sickle Cell Anemia?
Although Sickle Cell Anemia is a relatively rare condition (about one in four
thousand Americans have some form of the disease), its significant impact on
the African American community and its life-threatening consequences have made
it one of the better-known genetic disorders. Approximately 80,000 (or about
one in 400) African Americans have some form of Sickle Cell Disease, and another
two million (or 1 in 12) African Americans carry the sickle cell trait —
a genetic predisposition toward the disease that can be passed down to their
children. Even though both sickle cell disease and trait are most common among
African Americans, other Americans who trace their ancestry back to the Mediterranean
region, South and Central America, Saudi Arabia, and India can also be affected.
Sickle cell disease is caused by a defect in the gene that controls the production of hemoglobin. Hemoglobin is the part of red blood cells that is responsible for carrying oxygen in the blood stream throughout the body. Defective hemoglobin produced by the sickle gene become stiff, causing the red blood cells to change from rounded, doughnut-shaped cells that can flow easily through small blood vessels, to pointy sickle-shaped cells. These sickle-shaped cells get stuck in narrow blood vessels and cause traffic jams that interrupt the flow of oxygen to various parts of the body. The body attempts to get rid of these abnormal cells by destroying them, creating sickle cell anemia (anemia is a condition caused by a subnormal level of hemoglobin or red blood cells) that, in turn, can lead to chronic fatigue and decreased resistance to infection.
When sickle-shaped cells form and create roadblocks in the vessels, a person has what is called a sickle cell crisis (also known as a painful crisis). Sickle cell crises can last from a few hours to a few days. The amount of pain caused by a crisis can be moderate and controlled by pain medications at home, or can be so excruciating that hospitalization and IV pain medications are required. Proper diet, exercise, and fluid intake can help reduce the frequency and severity of sickle cell crises. In the severe form, these crises can cause damage to the lungs, kidneys, liver, and bones, and bring about leg ulcers and blindness.
In order to get sickle cell disease, a person must get a defective hemoglobin gene from both parents. If a person gets only one defective gene, they have sickle cell trait, and can pass the sickle gene to their children. People with sickle cell trait usually don't experience health problems, but may occasionally have a painful crisis when they're in environments with low oxygen pressure (e.g., when flying on un-pressurized aircraft).
Current treatment of sickle cell disease consists of antibiotic regimens to fight infection, and blood transfusions, when necessary, to treat anemia. Many states now routinely screen newborns for sickle cell disease. Early detection and treatment of the disease are, in part, responsible for increasing the life expectancy of those who have sickle cell disease from young adulthood into the mid-forties.
To learn more about sickle cell disease, or how you can help work for a cure, check out the American Sickle Cell Anemia Association web site.