BETA-GLOBIN GENE HAPLOTYPES IN EGYPTIAN SICKLE-CELL DISEASE AND BETA-THALASSEMIA

Introduction: This study was a collaborative investigation between Egy pt and Saudi Arabia. The major aim of the study was to identify the be ta(s) globin gene haplotype in Egyptian sickle cell disease and beta-t halassaemia patients. Material and methods: Since the sickle cell (Hb S) gene frequency is low in Egypt, only 6 patients suffering from sick le cell anemia, 4 patients suffering from Hb S/beta degrees-thalassemi a, 4 patients suffering from Hb S/beta(+) thalassaemia and 23 patients suffering from beta-thalassaemia major were included in this study. B lood collected in EDTA was used for the extraction of DNA. The beta-gl obin gene cluster was amplified using polymerase chain reaction and th e DNA fragment generated were restricted with different restriction en donucleases (Xmn I, Hind III, Hinc II and Ava II). The fragments obtai ned were separated by electrophoresis and the presence (+) or absent ( -) of the restriction site was determined from the size of the fragmen t generated. Frequency of each restriction site was calculated and bet a-globin gene haplotypes were constructed. Results: Significant differ ences were encountered in the frequency of the restriction sites and t he 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 ch romosomes) had this haplotype compared to 2.17% of beta-thal. major pa tients (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 hap lotypes associated with sickle cell and beta-thal. genes in Egyptians and showed significant variations.