The Xmn1 polymorphic site 5′ to the Gγ gene and its correlation to the Gγ:Aγ ratio, age at first blood transfusion and clinical features in β-Thalassemia patients from Western Iran

β-Thalassemia is the most common single gene disorder in Iran and more than 25,000 affected individuals have been reported. It has been reported that in patients with β-thalassemia in the presence of Xmn1 polymorphic site the level of Hb F and ^Gγ: ^Aγ ratio is increased. The prevalence of Xmn1 polymorphic site, ^Gγ: ^Aγ ratio and Hb F in 197 β-thalassemia major patients from the Kermanshah Province of Iran were studied. The Xmn1 polymorphic site was determined by PCR-RFLP procedure. The levels of ^Gγ and ^Aγ chains were detected by HPLC. The percent of Hb F was determined using electrophoresis method. In β-thalassemia major patients the frequency of presence Xmn1 was 0.39. The mean of ^Gγ: ^Aγ ratio was found to be 2.5. In the present study it was found that in the presence of Xmn1 polymorphic site ^Gγ percent and ^Gγ: ^Aγ ratio were significantly increased (P = 0.01) and the clinical features such as splenomegaly and bone marrow expansion were significantly improved (P = 0.01). We found that in the presence of Xmn1 polymorphic site on both chromosomes (+/+) the level of Hb F tended to be increased compared to the absence of Xmn1 (−/−). The present investigation has studied the frequency of Xmn1 polymorphic site in β-thalassemia major patients from Western Iran and has revealed that the presence of this polymorphic site caused a positive influence on Hb F production and the ^Gγ percent which could improve the clinical symptoms of β-thalassemia patients.