Hemoglobin A2 is elevated in which disease?

Hemoglobin A2 is elevated primarily in beta-thalassemia due to the underlying genetic defect in the beta-globin chains of hemoglobin. In beta-thalassemia, the body has reduced production of beta globin, which leads to an imbalance in the production of alpha and beta globin chains. This results in a compensatory increase in the production of Hemoglobin A2, which is made up of two delta chains and two alpha chains.

As beta-thalassemia progresses, the proportion of Hemoglobin A2 can rise significantly, often exceeding the 3.5% threshold that is commonly used as a diagnostic marker for the disease. This is critical for differentiating beta-thalassemia from other anemias, as elevated Hemoglobin A2 is characteristic of the disorder and assists in its diagnosis.

Opposed to this, conditions like sickle cell anemia, pernicious anemia, and iron deficiency anemia do not typically feature elevated levels of hemoglobin A2. Sickle cell anemia is primarily associated with the presence of Hemoglobin S instead. Meanwhile, pernicious anemia is characterized by a deficiency in vitamin B12 leading to ineffective erythropoiesis and macrocytic anemia, and iron deficiency anemia is tied to low