Microcytic hypochromic anemia is a common condition in clinical practice and alpha-thalassemia has to be considered as a differential diagnosis. Molecular diagnosis of α-thalassemia is possible by polymerase chain reaction. The aim of this study was to evaluate the frequency of α-gene numbers in subjects with microcytosis. In total, 276 subjects with microcytic hypochromic anemia [MCV<80fl; MCH<27pg] were studied. These include 125 with thalassemia trait, 48 with thalassemia major, 26 with sickle-cell thalassemia, 15 with E beta-thalassemia, 40 with iron-deficiency anemia, 8 with another hemolytic anemia, and 14 patients with no definite diagnosis. Genotyping for −α3.7 deletion, −α4.2 deletion, Hb Constant Spring, and α-triplications was done with polymerase chain reaction. The overall frequency of −α3.7 deletion in 276 individuals is 12.7%. The calculated allele frequency for α-thalassemia is 0.09. The subgroup analysis showed that co-inheritance of α-deletion is more frequent with the sickle-cell mutation than in other groups. We were able to diagnose 1/3 of unexplained cases of microcytosis as α-thalassemia carriers. The α-gene mutation is quite common in the Indian subcontinent. Molecular genotyping of α-thalassemia helps to diagnose unexplained microcytosis, and thus prevents unnecessary iron supplementation.
alpha 3.7 deletions evaluation of anemia microcytic hypochromic anemia North India single alpha-gene deletion