Sickle cell disease is an inherited
blood disorder, passed from parent to child. Children with sickle cell disease
have two defective
hemoglobin S genes, one from each parent. Various forms of
sickle cell disorder occur when a person inherits one
hemoglobin S gene (sickle cell gene) from one parent and one other type of defective
hemoglobin gene from the other parent.
Normally, a person inherits two genes that tell the body to
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, and their bodies don't make sickled blood cells. But they can
pass the defective hemoglobin S gene to their children.