In alpha-thalassemia trait,electrophoresis shows:March 2005
Increased HbF and normal HbA2
Normal HbF and normal HbA2
Normal HbF and decreased HbA2
Decreased HbF and normal HbA2
Ans. B: Normal HbF and normal HbA2Alpha (0) thalassemia -Individuals with this disorder are not able to produce any functional alpha-globin and thus are unable to make any functional hemoglobin A, F, or A2. This leads to the development of hydrops fetalis, also known as hemoglobin Ba, a condition that is incompatible with extra uterine life.Alpha (+) thalassemia - genetic mutations that result in decreased production of alpha-globin usually due to the functional deletion of 1 of the 4 alpha globin genes. Based on the number of inherited alpha genes, it is subclassified into 3 general forms:Thalassemia (-u/ a a) is characterized by inheritance of 3 normal a-genes. These patients are referred to clinically as silent carrier of alpha thalassemia. Other names for this condition are alpha thalassemia minima, alpha thalassemia-2 trait, and heterozygosity for alpha (+) thalassemia minor. The affected individuals exhibit no abnormality clinically and may be hematologically normal or have mild reductions in red cell mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH).Inheritance of 2 normal alpha genes due to either heterozygosity for alpha (0) thalassemia (u a/ --) or homozygosity for alpha (+) thalassemia (-u/-a) results in the development of alpha thalassemia minor or alpha thalassemia-1 trait. The affected individuals are clinically normal but frequently have minimal anemia and reduced mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH).Inheritance of one normal alpha gene (-a/ --) results in abundant formation of hemoglobin H. This condition is known as ElbH disease. The affected individuals have moderate to severe lifelong hemolytic anemia, modest degrees of ineffective erythropoiesis, splenomegaly and variable bony changesPersons with alpha-thalassemia traits have normal HbA2 and HbF levels whereas beta- thalassemia patients have elevated HbA2