Sickle cell trait refers to which genotype?

• A. AS
• B. SS
• C. SS Trait
• D. AA

Answer: (A)

Sickle cell trait is the heterozygous state, meaning a person has one normal beta-globin gene and one sickle beta-globin gene. This genotype is represented as AS, where HbA (normal hemoglobin) and HbS (sickle hemoglobin) are both produced. Because the normal hemoglobin predominates, individuals with this genotype are typically asymptomatic carriers and do not have the full sickle cell disease. They can tolerate normal conditions, though under extreme stress such as severe dehydration, high altitude, or hypoxia, some red cells may sickle temporarily.

In contrast, having two sickle genes (SS) leads to full sickle cell disease with significant symptoms, and having two normal genes (AA) results in normal hemoglobin with no trait. The option labeled as “SS trait” is not a standard genotype term, and AA is simply normal.