Beta globin gene haplotypes in Egyptian sickle cell disease and beta-thalassemia

Introduction: This study was a collaborative investigation between Egypt and Saudi Arabia. The major aim of the study was to identify the beta(s) globin gene haplotype in Egyptian sickle cell disease and beta-thalassaemia patients. Material and methods: Since the sickle cell (Hb S) gene frequency is low in Egypt, only 6 patients suffering from sickle cell anemia, 4 patients suffering from Hb S/beta degrees-thalassemia, 4 patients suffering from Hb S/beta(+) thalassaemia and 23 patients suffering from beta-thalassaemia major were included in this study. Blood collected in EDTA was used for the extraction of DNA. The beta-globin gene cluster was amplified using polymerase chain reaction and the DNA fragment generated were restricted with different restriction endonucleases (Xmn I, Hind III, Hinc II and Ava II). The fragments obtained were separated by electrophoresis and the presence (+) or absent (-) of the restriction site was determined from the size of the fragment generated. Frequency of each restriction site was calculated and beta-globin gene haplotypes were constructed. Results: Significant differences were encountered in the frequency of the restriction sites and the beta-globin gene haplotypes in the patient groups. Over 91% of the SCA patients (11/12 chromosomes) had the Benin haplotype, while 37.5% (3/8 chromosomes) Hb S beta degrees and 50% S beta(+) patients (4/8 chromosomes) had this haplotype compared to 2.17% of beta-thal. major patients (1/46 chromosomes). Discussion: The pattern of beta-globin gene haplotypes in the beta-globin thal. major patients was significantly different from the SCA group. This study revealed beta-globin gene haplotypes associated with sickle cell and beta-thal. genes in Egyptians and showed significant variations.