Sickle cell disease is an inherited disorder. More specifically, sickle cell disease is an autosomal recessive disease. This means that to have the disease, you must inherit a gene for the disease from both parents.

• Normally, a person inherits two genes that tell the body to produce normal hemoglobin A. One gene comes from each parent.
• People who inherit one defective hemoglobin S gene and one normal hemoglobin A gene have sickle cell trait. These people don't have symptoms of sickle cell disease, nor do their bodies make sickled blood cells. However, they can pass the defective hemoglobin S gene to their children.
• Sickle cell disease occurs when a person inherits one defective hemoglobin S gene from each parent.
• Similar sickle cell disorders occur when a person inherits a hemoglobin S gene from one parent and another type of defective hemoglobin gene from the other parent. Sickle cell disease is a sickle cell disorder.

For more information, see autosomal recessive disease and an illustration of this risk.