ALPHA-THALASSEMIA: DELETION ANALYSIS IN IRAN

Background-Alpha-thalassemia is one of the most prevalent hemoglobin disorders in the world. The molecular basis of α-thalassemia is deletions of variable lengths involving one or both α-genes at the α-globin gene cluster. Functional point mutations leading to inactivation of the α-genes are less frequent. So far, no comprehensive population screening for α-thalassemia has been performed in Iran and no molecular diagnostic services are available for this disease. As a result, a considerable number of patients with microcytic, hypochromic anemia and normal Hb A2 levels might be misdiagnosed as silent β-thalassemia. The aim of the present study was to determine the spectrum of common α- thalassemia mutations in Iran. Methods-A total of 57 Iranian subjects were randomly chosen from a pool of patients with microcytic hypochromic anemia and negative β-thalassemia genotyping. They were tested for the 2 most frequent α-thalassemia deletions (-α3.7, -α4.2). Analysis was performed using deletion-specific PCR amplification followed by agarose gel electrophoresis of the resulting PCR fragments. Results- No -α4.2 deletion was detected, however, 18 (31.6%) out of 57 analyzed cases demonstrated the -α3.7 deletion, either in the homozygous or heterozygous state. Conclusion-This study suggests that the -α3.7 deletion is a common cause of microcytic hypochromic anemia in Iran. The results are in accordance with previous studies, which report a remarkably high frequency of -α3.7 in the Middle East. Routine screening for this mutation will improve the molecular diagnosis of anemia in Iran.