Wide Spectrum of Mutations in the Beta-Globin Gene Causing Beta-Thalassemia Major in Southwest Iran

Beta-thalassemia (β-thalassemia) is characterized by the reduced synthesis of the hemoglobin beta chain. Nowadays, more than 200 disease-causing mutations in beta-globin (β-globin) gene have been identified. Betathalassemia is the most common monogenic disease worldwide and one of the widespread hereditary disorders in Iran. Considering the vast spectrum of beta-thalassemia mutations, it has multi-ethnic population. The gene frequency of betathalassemia is high and varies considerably in each region. Therefore, it is necessary to determine the frequency and distribution of beta-thalassemia mutations in different regions. In the present study, two hundred and two beta-thalassemia major patients were subjected for genomic DNA extraction from whole blood. Amplification and subsequent sequencing of the beta-globin gene has been made by specific primers. Thirty mutations were found in 404 studied alleles. Our results show that IVSII-1(G>A) with 21.3% (86/404 alleles) represents the most common mutation, followed by the four mutations namely CD36/37 (-T) (16%), IVSI-110(G>A) (17.8%), IVSI-5(G>C) (6.9 %) and CD5 (-CT) (5.2%), respectively. Our findings indicate that the Khuzestan population possesses a wide variety of thalassemia allelic distribution. These results can be used as basis for prenatal diagnosis of beta-thalassemia, especially in the south west of Iran.