Alpha-thalassemia subtypes include silent carrier, carrier, major, and which disease?

Alpha-thalassemia subtypes include silent carrier, carrier, major, and which disease?

• A. Hgb H Disease
• B. Sickle Cell Disease
• C. Beta-Thalassemia Minor
• D. Polycythemia Vera

Answer: (A)

Alpha-thalassemia subtypes are defined by how many alpha-globin genes are deleted. With three gene deletions, the disease that fits this pattern is Hemoglobin H disease. In HbH disease, remaining beta-globin chains form unstable beta4 tetramers (HbH) that precipitate in red blood cells, causing hemolytic anemia with symptoms ranging from mild to moderate depending on the individual. If all four alpha-globin genes are deleted, hydrops fetalis due to Hb Barts (gamma4) occurs and is usually fatal in utero or shortly after birth. The other options involve different conditions (sickle cell and beta-thalassemia) or non-hemoglobin disorders, so they don’t align with the alpha-thalassemia deletion pattern described.

Alpha-thalassemia subtypes are defined by how many alpha-globin genes are deleted. With three gene deletions, the disease that fits this pattern is Hemoglobin H disease. In HbH disease, remaining beta-globin chains form unstable beta4 tetramers (HbH) that precipitate in red blood cells, causing hemolytic anemia with symptoms ranging from mild to moderate depending on the individual. If all four alpha-globin genes are deleted, hydrops fetalis due to Hb Barts (gamma4) occurs and is usually fatal in utero or shortly after birth. The other options involve different conditions (sickle cell and beta-thalassemia) or non-hemoglobin disorders, so they don’t align with the alpha-thalassemia deletion pattern described.