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Sickle Cell Anemia. What Causes Sickle Cell Anemia ?. An inherited condition that is autosomal recessive People with Sickle Cell Anemia inherit two copies of the recessive sickle cell gene (S), one from each parent. The sickle cell gene makes abnormal
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What Causes Sickle Cell Anemia? An inherited condition that is autosomal recessive People with Sickle Cell Anemia inherit two copies of the recessive sickle cell gene (S), one from each parent. The sickle cell gene makes abnormal hemoglobin. The abnormal hemoglobin clumps together when it gives up its oxygen. These clumps are crystals that cause red blood cells to become shaped like a sickle, instead of the normal disk shape.
What Causes Sickle Cell Trait? • People who inherit only one copy of the sickle cell gene (from one parent) will not have Sickle Cell Anemia. They will have Sickle Cell Trait. • People with Sickle Cell Trait generally have no symptoms and lead normal lives. Like people with Sickle Cell Anemia, however, they can pass the sickle cell gene on to their children. • People with Sickle Cell Trait are also resistant to Malaria, leading to an increase in this genotype and phenotype.
Malaria and Sickle Cell Trait • People with normal hemoglobin A are susceptible to death from malaria. • People with Sickle Cell Anemia are susceptible to death from the complications of their disease. • People with Sickle Cell Trait, who have one gene for hemoglobin A and one gene for hemoglobin S, have a greater chance of surviving malaria and do not suffer adverse consequences from the hemoglobin S gene.
People who have Sickle Cell Trait are resistant to Malaria. • Therefore, Malaria is causing an increase in the number of people who have Sickle Cell Trait.
Prevalence of Sickle Cell • Sickle hemoglobin is found in people whose ancestors come from Africa, the Arabian States, South India and from countries around the Caribbean Sea, such as Puerto Rico, Cuba, Haiti and Jamaica, and also from countries around the Mediterranean Sea, such as Italy, Cyprus, Greece, Turkey, and Syria. • Sickle Cell Trait occurs in approx. 1 in 12 (8%) African-Americans. Sickle cell anemia occurs in approx.1 in 375 African-Americans and affects more than 50,000 Americans in total.
