MRCP UK EXAMINATIONS

Detailed explanation-1: -Hb A2 is increased in beta thalassemia because the relative lack of beta globin allows more delta chains to be incorporated into hemoglobin. Beta thalassemia is caused by mutations in the beta globin gene locus on chromosome 11.

Detailed explanation-2: -Hemoglobin A2 levels in normal adults are rarely greater than 3.5%. In patients heterozygous for beta-thalassemia, they average about 5% but do not usually exceed 7%. We studied a family in which four patients with heterozygous beta-thalassemia had HbA2 levels of 8.4% to 11.2%.

Detailed explanation-3: -Heterozygous beta thalassemia minor (HBT) is a benign blood disorder caused by a hereditary reduction in beta globin synthesis, which often leads to mild anemia and is characterized by hypochromic microcytic erythrocyte indexes [1].