In beta-thalassemia, one genetic mutation results in which condition?

• A. Beta thalassemia major
• B. Thalassemia minor
• C. Sickle cell disease
• D. No disease

Answer: (B)

Beta-thalassemia severity depends on how many beta-globin gene copies are mutated. With one mutated beta-globin gene, you have beta-thalassemia trait (minor): a carrier state where symptoms are usually mild or absent, though some people may have subtle anemia, and they can pass the mutation to their children. Beta-thalassemia major happens only when both beta-globin genes are mutated, leading to severe anemia in early life. Sickle cell disease arises from a different mutation in the beta-globin gene that produces hemoglobin S, not from one beta-thalassemia mutation. No disease would not apply because a mutation is present. So one genetic mutation best corresponds to thalassemia minor.