Alpha-thalassemia major results in which outcome?

Alpha-thalassemia major results in which outcome?

• A. Affected foetus suffers from severe anaemia, which leads to its death before birth or shortly after birth
• B. No symptoms
• C. Mild anaemia
• D. Regular transfusions

Answer: (A)

The key idea is that alpha-thalassemia major happens when all four alpha-globin genes are missing, so the fetus cannot produce alpha-globin chains. Without alpha chains, hemoglobin can't form properly, and the fetus relies on abnormal Hb Bart’s (gamma4) that carries oxygen very poorly. This severe imbalance causes profound anemia and often hydrops fetalis, leading to death before birth or within the neonatal period. That outcome—death in utero or shortly after birth due to severe anemia—is the typical course for alpha-thalassemia major, making the described outcome the best fit. The other scenarios reflect milder forms: fewer gene deletions can cause no symptoms or only mild anemia, and regular transfusions aren’t the expected outcome for this lethal prenatal condition.

The key idea is that alpha-thalassemia major happens when all four alpha-globin genes are missing, so the fetus cannot produce alpha-globin chains. Without alpha chains, hemoglobin can't form properly, and the fetus relies on abnormal Hb Bart’s (gamma4) that carries oxygen very poorly. This severe imbalance causes profound anemia and often hydrops fetalis, leading to death before birth or within the neonatal period. That outcome—death in utero or shortly after birth due to severe anemia—is the typical course for alpha-thalassemia major, making the described outcome the best fit. The other scenarios reflect milder forms: fewer gene deletions can cause no symptoms or only mild anemia, and regular transfusions aren’t the expected outcome for this lethal prenatal condition.