Sickle Cell Trait

What is Sickle Cell Trait ?

Sickle cell trait (AS) is not a “type” of sickle cell disease. It is an inherited condition in which both hemoglobin A and S are produced in the red blood cells, always more A than S. Individuals with sickle cell trait are generally healthy.


Sickle cell conditions are inherited from parents in much the same way as blood type, hair color and texture, eye color and other physical traits. The types of hemoglobin a person makes in the red blood cells depend upon what hemoglobin genes the person inherits from both parents. Like most genes, individuals inherit one from each parent.

If one parent has sickle cell anemia (SS) and the other parent has normal (AA) blood, all of the children will have sickle cell trait. If one parent has sickle cell anemia (SS) and the other parent has sickle cell trait (AS), there is a 50% chance (1 chance out of 2) of having a baby with either sickle cell disease or sickle cell trait with each pregnancy. When both parents have sickle cell trait (AS), they have a 25% chance (1 chance out of 4) of having a baby with sickle cell disease with each pregnancy.

How will I know if I have the Trait?

A simple painless blood test followed by a laboratory technique called Hemoglobin Electrophoresis will determine the type of hemoglobin. When an electric charge is passed through a solution of hemoglobin, distinct hemoglobins move at different distances, depending on their composition. This technique differentiates between normal hemoglobin (A), sickle hemoglobin (S), and other different hemoglobins (such as C, D, E, etc.).
Research for the disease did not really begin until about 1952 when researchers discovered that the inherited disease existed in a defect of the hemoglobin