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How does the sickle cell trait differ from sickle cell anemia?

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The distinction between sickle cell trait and sickle cell anemia lies in the inheritance of the hemoglobin S (HbS) gene.1

Sickle Cell Anemia: This is a hereditary disease that occurs when a person inherits the variant HbS gene from both parents (the homozygous state). It causes red blood cells to become rigid and sickle-shaped, leading to chronic anemia, severe pain, and organ damage due to obstructed blood flow.1
Sickle Cell Trait: This occurs when an individual inherits the HbS gene from one parent and a normal hemoglobin gene (HbA) from the other (the heterozygous state). Because these individuals possess both HbA and HbS, their red blood cells are less likely to sickle. Consequently, the condition is usually asymptomatic, and individuals with the trait generally have the same life expectancy as the general population.12

While sickle cell anemia requires ongoing medical management, those with the trait are typically healthy, though they may experience symptoms during extreme exertion at high altitudes. Interestingly, the trait persists in certain populations because it provides resistance to malaria.1