Definition
A sickle cell is an abnormally shaped red blood cell that looks like a crescent or sickle. This shape is caused by a genetic mutation in the hemoglobin protein. Sickle cells are rigid and can block blood flow in small vessels, leading to pain and tissue damage. Sickle cell disease is a hereditary condition where many red blood cells are sickle-shaped. Normal red blood cells are flexible and disc-shaped. Sickle cells have a shorter lifespan than normal red blood cells. They cause significant health issues.