What causes sickle cell anaemia?

What causes sickle cell anaemia?

• A. Inherit 2 HbA
• B. Inherit 2 HbS
• C. Inherit 1 HbS and 1 HbA
• D. Inherit HbC and HbS

Answer: (B)

Sickle cell anemia occurs when both copies of the beta-globin gene carry the mutation that produces HbS. With two HbS alleles, red blood cells are prone to polymerizing HbS when oxygen is low, causing the cells to sickle, leading to hemolysis and the characteristic anemia and crises. If one HbS allele and one normal HbA allele are present, you have sickle cell trait, usually without symptoms. Two normal HbA alleles mean no disease, and HbC with HbS is a different sickle-related condition, not the classic sickle cell anemia.

Sickle cell anemia occurs when both copies of the beta-globin gene carry the mutation that produces HbS. With two HbS alleles, red blood cells are prone to polymerizing HbS when oxygen is low, causing the cells to sickle, leading to hemolysis and the characteristic anemia and crises. If one HbS allele and one normal HbA allele are present, you have sickle cell trait, usually without symptoms. Two normal HbA alleles mean no disease, and HbC with HbS is a different sickle-related condition, not the classic sickle cell anemia.