Identification of β-globin gene mutations among transfusion-dependent β-thalassemia patients

Abstract

Abstract BACKGROUND: β-thalassemias are widely distributed in Mediterranean and Middle Eastern countries, including Iraq. There are more than 400 transfusion-dependent β-thalassemia patients registered in the thalassemia center. β-thalassemia is a significant problem in Karbala as well as other regions of Iraq. The detection of the most frequent mutations is significant to the implementation of an effective preventive program in this area because of the significant burden it places on the local health authorities, patients, and their families. OBJECTIVES: To define the most common mutations and their frequencies among patients with transfusion-dependent β-thalassemia and to evaluate the reverse hybridization strip assay method for the detection of β-thalassemia mutations. PATIENTS, MATERIALS AND METHODS: Sixty transfusion-dependent β-thalassemia patients were recruited from the thalassemia center in Karbala. Blood samples were aspirated from each patient just before blood transfusions for CBC, reticulocyte count, DNA extraction, PCR amplification, and identification of the mutations by reverse hybridization technique using the β-Globin strip assay method. RESULTS: A total of 60 patients with 120 chromosomes were studied, searching for the most common mutations causing β-thalassemia. Among the twelve identified mutations, the six most frequent mutations represented 79.16% of all β-globin defects. These mutations were IVSII-1 (30.83%), IVSI-110 (15.83%), Codon 5 (10.83%), Codon 44 (8.33%), IVSI-1 (6.67%), and IVSI-5 (6.67%). The detection rate of the method used in our population was 96.66%. CONCLUSION: The most frequent mutations encountered were IVSII.1 and IVSI-110, while IVS 2.745 was the least common mutant allele. Reverse hybridization strip assay molecular techniques used in the current study provide an extremely quick, precise, and simple to carry out molecular diagnostic technique for the detection of β-thalassemia mutations.