Phenotype-Genotype Variation In a Sample of Egyptian Patients with Uncommon Beta Thalassemia Mutations

Abstract

Background: Beta-thalassemias represent a group of hereditary blood disorders characterized by anomalies in the synthesis of the beta chains of hemoglobin resulting in variable phenotypes ranging from severe anemia to clinically asymptomatic individuals. Three main forms have been described: Thalassemia major, Thalassemia intermedia and Thalassemia minor. In each population only a few common mutations in the β globin have been found to be responsible for β-thalassemia, which indicate population differences. In Egypt β- thalassemia occurs in high frequency and premarital screening has been implemented for this disorder. Few comprehensive mutational screening for the β–globin gene locus has been carried so far in Egypt. Objective: This study was designed with the objective to sequence the β-globin gene in β-thalassemia patients with uncommon mutations among Egyptian population and to investigate the genotype phenotype correlation. Subjects and Methods: 30 β -thalassemia patients were enrolled in the study and hematological and biochemical data were recorded after full clinical evaluation, DNA was extracted and the β -globin gene was sequenced. Results: Direct sequencing of the β -globin gene identified a total of 9 previously reported point mutations. β -thalassemia patients were either homozygous, heterozygous or compound heterozygous for those mutations, Conclusion: this study characterizes some of the uncommon mutations and variants in the β -globin gene in Egypt and correlate between the genotypes and the phenotypes of the cohort of patients enrolled. Recommendations: Sequencing of more Beta thalassemia Patients whose mutations couldn’t be identified by Regular methods to establish a beta globin gene database specicifc for Egyptian population