Recessive Inheritance
According to the Mayo Clinic, sickle cell anemia is caused by a genetic mutation of the gene that produces hemoglobin. The gene is inherited through a pattern called "autosomal recessive inheritance," which means that the father and the mother must carry and pass on the defective gene for a child to be born with sickle cell anemia. Sickle cell patients have deformed "sickle" shaped blood cells that become sticky and rigid, and which can block or slow oxygen or blood flow to body parts.
Sickle Cell Trait
The National Heart, Lung and Blood Institute states that a person who has one normal hemoglobin gene and one defective hemoglobin gene might carry some sickle cells in their bloodstream, but because they also produce normal hemoglobin they typically don't experience the symptoms of sickle cell anemia. They are, however, carriers of the sickle cell and could pass it on to their offspring.
Chance of Occurrence
When couples who both carry a sickle cell gene have children, the chance of a child being born with sickle cell anemia is 25 percent. The child also has a 25 percent chance of having normal hemoglobin and no signs of the disease, as well as a 50 percent chance of being a carrier only. These percentages hold for each successive pregnancy. While there are treatments and pain management programs for those with sickle cell anemia, there is no cure for the disease.
