Thalassemic mutations in Southern Iran

Approximately 180 mutations have been described in beta-thalassemia worldwide with specific spectrum in each ethnic population. This study determines the spectrum and the frequency of beta-thalassemia mutations in patients with beta-thalassemia trait and sickle cell-beta-thalassemia. Fifteen compound heterozygous sickle cell thalassemia [SCT] and 23 beta-thalassemia trait patients were studied using reverse dot blot, denaturing gradient gel electrophoresis and direct genomic sequencing. We detected distinct beta-thalassemia alleles in 15 compound heterozygous of SCT and 23 beta-thalassemia trait patients. The most common mutation was IVSII-1[G-A], found in 15 of the 38 thalassemia chromosomes. IVSII.1 [G-A] mutation is a single nucleotide change of G to A at intervening sequence 2 position 1 of beta-globin gene, detected in 11 out of 23 chromosomes in A/beta-thalassemic patients and in four out of 15 chromosomes of SCT patients. This mutation constituted about 39% of the mutations in both groups. The -25bp 3 IVSI, deletion of 25 base pairs from 3' end of intervening sequence 1 of beta-globin gene, was found to be the second prevalent mutation among all chromosomes. Defining thalassemia mutations are necessary to establish prenatal diagnosis programs leading to lower medical cost. Amongst 10 different types of mutation detected in beta- thalassemic patients from South of Iran, two mutations of IVSII-1[G-A] and -25bp 3 IVSI were the most predominant beta-thalassemic alleles