How is sickle cell anemia inherited?
Sickle cell anemia is inherited as an autosomal (meaning that the gene is not linked to a sex chromosome) recessive condition whereas sickle cell trait is inherited as an autosomal dominant trait. This means that the gene can be passed on from a parent carrying it to male and female children. In order for sickle cell anemia to occur, a sickle cell gene must be inherited from both the mother and the father, so that the child has two sickle cell genes. The inheritance of just one sickle gene is called sickle cell trait or the “carrier” state. Sickle cell trait does not cause sickle cell anemia. Persons with sickle cell trait usually do not have many symptoms of disease and have normal hospitalization rates and life expectancies. Sickle cell trait is present in some two million blacks in the United States (8% of the U.S. black population at birth). When two carriers of sickle cell trait mate, their offspring have a one in four chance of having sickle cell anemia. (In some parts of Africa,
