Sickle cell disease results from a mutation that alters the gene that controls the production of hemoglobin A, a pigment inside the red blood cells that carries the oxygen to all parts of the body. These cells are fragile and have a shortened life span resulting in anemia and most of the medical complications that are seen in sickle cell anemia. Sickle cell disease is inherited as an autosomal recessive condition. This condition occurs in the presence of two copies of a mutant or non-working gene. Each parent of an affected individual carries one copy of the non-working gene and one copy of the working gene and is referred to as a carrier.
Carriers generally have no symptoms.
When 2 carriers marry, they have a 1 in 4 chance with every pregnancy of having an affected child, a 2 in 4 chance of having a carrier child, and 1 in 4 chance of having a child who is free of the sickle cell gene. It is estimated that 1 in 10 African Americans in the U.S. is a carrier for the sickle cell gene and 1 in 400 is affected with the disease. Sickle cell disease and carrier state are easily diagnosed by specific blood tests. In addition, sickle cell disease can be diagnosed prenatally. Most newborns in the USA are screened for sickle cell disease to identify affected infants and provide them and their families with early treatment, anticipatory guidance, education and genetic counseling.