Sickle cell trait is a hemoglobin genotype AS, which means that a person inherits one normal allele and one abnormal allele encoding hemoglobin S. Sickle cell trait is generally regarded as a benign condition, and people with sickle cell trait usually live normal lives without symptoms of sickle cell disease. However, individuals with sickle cell trait may have rare complications, such as severe dehydration and high-intensity physical activity that can lead to serious health issues, including sudden death. Sickle cell trait is not the same as sickle cell disease (SCD), which is caused by inheriting two copies of the gene that produces beta-globin, a protein needed to produce normal hemoglobin (hemoglobin A, genotype AA) . Sickle cell disease and the associated trait are most prevalent in Africa and Central America, which is attributed to natural selection: the sickle-cell trait confers a survival advantage in areas with a high occurrence of malaria, which has a high death rate among individuals without the trait.