Role of XmnI(G) Polymorphism in Hydroxyurea Treatment and Fetal Hemoglobin Level at Isfahanian Intermediate β-Thalassemia Patients

BACKGROUND: β-thalassemia is the most common monogenic disorder in human. The (CT) polymorphism at -158 upstream region of the γ(G)-globin gene and pharmacological factors such as hydroxyurea have been reported to influence γ-globin gene expression and the severity of clinical symptoms of β-thalassemia. METHODS: In the present study, 51 β-thalassemia intermediate patients were studied. Xmn1γ(G) polymorphism genotype was determined using Tetra-Primer ARMS-PCR technique. Hemoglobin (Hb) and fetal hemoglobin (HbF) levels were determined by gel electrophoresis. RESULTS: Of 51 patients, 35 (68.6%) patients were heterozygous (CT) and 16 (31.4%) patients were homozygous (CC). Of 30 patients under treatment by hydroxyurea, 20 (66.7%) patients were heterozygous (CT) and 10 (33.3%) patients were homozygous (CC). Our results demonstrated that in the heterozygous (CT) genotype, the Hb (9.58 ± 1.25 gm/dl) and HbF (89.30 ± 21.87) levels were significantly higher in comparison with homozygous (CC) genotype (7.94 ± 1.34 gm/dl and 70.32 ± 40.56, respectively). Furthermore, we observed that after drug usage, the Hb and HbF levels in patients with heterozygous (CT) genotype (0.7 ± 1.26 gm/dl and 5.95±14.8, respectively) raised more in comparison with homozygous (CC) genotype (0.26 ± 1.43 gm/dl and 0.8 ± 1.31, respectively). CONCLUSION: Hb and HbF levels in the patients carrying T allele are increased significantly, and they also response to hydroxyurea treatment.