Individuals homozygous for defective B globin gene have which thalassemia condition?

Individuals homozygous for defective B globin gene have which thalassemia condition?

• A. Iron deficiency anemia
• B. Sickle cell disease
• C. Thalassemia minor
• D. Thalassemia major

Answer: (D)

Two defective copies of the beta-globin gene disrupt production of beta chains, causing beta-thalassemia major. Without sufficient beta chains, there’s an imbalance of globin synthesis leading to ineffective erythropoiesis, severe microcytic hypochromic anemia in early childhood, and often need for regular transfusions with complications like iron overload and growth issues. If only one beta-globin gene is defective, the result is a milder carrier state called thalassemia minor. Iron deficiency anemia is unrelated to beta-globin gene defects, and sickle cell disease arises from a different mutation that changes one amino acid in the beta-globin chain (HbS), not from a complete lack of beta-chain production.

Two defective copies of the beta-globin gene disrupt production of beta chains, causing beta-thalassemia major. Without sufficient beta chains, there’s an imbalance of globin synthesis leading to ineffective erythropoiesis, severe microcytic hypochromic anemia in early childhood, and often need for regular transfusions with complications like iron overload and growth issues. If only one beta-globin gene is defective, the result is a milder carrier state called thalassemia minor. Iron deficiency anemia is unrelated to beta-globin gene defects, and sickle cell disease arises from a different mutation that changes one amino acid in the beta-globin chain (HbS), not from a complete lack of beta-chain production.