β-globin mutations in Egyptian patients with β-thalassemia

Abstract

β-thalassemia is a common hereditary disorder, particularly in Middle Eastern countries. More than 200 mutations in the β globin gene have been reported; most are point mutations in functionally important regions (HBB; OMIM #141900)). The spectrum of mutations varies significantly between different geographical regions; only a few common mutations of β-globin cause β-thalassemia in each population. The aim of this study was to determine the spectrum of mutations that cause β-thalassemia in the North Coast of Egypt and to investigate their correlation with the phenotypic severity of β-thalassemia. We carried out our study with a total of 47 Egyptian patients (25 male and 22 female) confirmed to have β-thalassemia. Evaluation of β-thalassemia mutations revealed the presence of 10 β-globin mutations. The most frequently encountered mutations were intronic: IVS 1.6 [T>C] (27.66%) and IVS 1.110 [G>A] (22.35%), followed by IVS 2.848 [C>A], IVS 1.1 (G>A), and IVS 2.745 [C>G]. We observed the exonic and promoter mutations less frequently. A homozygous mutation was found in 24 patients (51%) and compound heterozygous mutations were found in 13 patients (28%). However, in 9 patients (19%), we identified only 1 mutation. In 1 patient (2%), we detected no mutation. The detection rate of the method that we used in our population was 88% (83 of the tested 94 alleles). The results we obtained did not reveal any correlation between genotype and phenotype among patients with β-thalassemia.