Sickle cell trait

Sickle cell trait (SCT) is the inheritance of one copy of the sickle-cell hemoglobin gene (HbS) from one parent and one normal hemoglobin gene (HbA) from the other. Carriers usually do not have symptoms of sickle cell disease, but rare adverse events have been documented under conditions of severe dehydration, high-altitude exertion, or extreme physical stress.

About 1 in 13 Black Americans carries SCT. The trait does not cause sickle cell disease, which requires two copies of the HbS gene. SCT does have implications for family planning and is the basis for newborn screening programs.