Sickle cell disease (SCD), also known as sickle cell anemia, is a condition that people are born with, and it affects a protein in the blood called hemoglobin. Hemoglobin helps carry oxygen in red blood cells. Normally, red blood cells are round and flexible, which allows them to move smoothly through blood vessels. However, in SCD, the red blood cells become misshaped, often looking like a crescent or "sickle" instead of being round. This happens because of a change in a gene that affects the hemoglobin. When the red blood cells sickle, they can't bend or move easily, and they can block the flow of blood to other parts of the body (National Heart, Lung, and Blood Institute, 2024). This can lead to pain, infections, and other serious problems. The biggest health risks of SCD happen when these sickled cells block blood flow to organs, which can lead to complications like stroke, lung problems, organ damage, disabilities, and, in severe cases, early death (American Society of Hematology).
People with SCD get two special genes for hemoglobin—one from each parent. These genes create a type of hemoglobin called hemoglobin S, which is not normal. SCD can also happen if a child gets one sickle cell gene (hemoglobin S) from one parent and a different type of faulty hemoglobin gene, like beta thalassemia or hemoglobin C, from the other parent (National Heart, Lung, and Blood Institute, 2024).
SCD is the most common inherited blood disorder in the United States, affecting an estimated 70,000 to 100,000 individuals (American Society of Hematology). While the disease can occur in people of any background, it is more prevalent among certain ethnic groups, including:
According to the Centers for Disease Control and Prevention (CDC, 2024):