Microcytic - Thalassemia

The hemoglobin electrophoresis pattern for patient #2 shows an increase in Hb F and a decrease in both Hb A and Hb A2. These results correlate best with which of these thalassemias? Beta thalassemia minor. Beta thalassemia major. Delta-beta thalassemia minor. Alpha thalassemia major.

Delta-beta thalassemia minor. Decreases in both Hb A and A2 and an increase in Hb F correlates with delta-beta thalassemia minor. Delta-Beta Thalassemia results from a deletion in both the delta and beta genes on chromosome 11, preventing the appropriate production of hemoglobins A2 and A respectively. The gamma genes on the affected chromosome increase their production of gamma globin thereby increasing the amount of HbF. Beta thalassemia minor is the result of one beta gene on chromosome 11 being defective that will show a minor decrease in beta globin due to the fact that one gene is still producing functioning beta globins. Beta thalassemia major is the result of both beta genes on chromosome 11 being defective that leads to a severe decrease in beta globin. Alpha thalassemia major is a deletion of all four alpha globin genes on chromosome 16 that leads to hydrops fetalis. Most patients with this die soon after birth or in utero.

Which hemoglobin will be increased in delta-beta thalassemia? Hb A. Hb A2. Hb F. Hb H.

Hb F. HbF is increased in delta-beta thalassemia. It is increased to 100% in delta-beta thalassemia major. In beta thalassemia HbA, a2ß2, is decreased or absent. In delta beta thalassemia HbA2, a2d2, is decreased. HbH is beta globin tetramer seen in alpha thalassemia HbH disease. HbH is not seen in beta thalassemia.

Which of the following alpha thalassemia syndromes has the genotype -a/aa ? Silent carrier. Alpha thalassemia minor. Hemoglobin H disease. Alpha thalassemia major.

Silent carrier. The genotype -a/aa is known as silent carrier. Only one of the four genes is missing. Individuals who are silent carriers show no clinical disease and demonstrate normal results during routine laboratory testing (Enough alpha chains can be made with only three functioning gene loci). This form of alpha thalassemia is usually discovered upon family studies. Alpha thalassemia minor occurs when two of the four alpha genes are missing (--/aa, -a/-a). Hemoglobin H disease occurs when three of the four alpha genes are missing (--/-a). Alpha thalassemia major occurs when all four of the alpha genes are missing.