Two β-globin cluster-linked polymorphic loci in thalassemia patients of variable levels of fetal hemoglobin

Objective: To correlate different polymorphisms of the beta-globin cluster with fetal hemoglobin (HbF) level in beta-thalassemia and E-beta thalassemia patients. Methods: Fifteen thalassemia patients, seven with high HbF and not requiring transfusion, eight with lower HbF and requiring transfusion were studied for beta-globin mutation, concurrent inheritance of alpha-thalassemia, RFLP haplotype, a C -> T polymorphism at -158 of G gamma and configuration of an (AT)(x)T-y motif at -540 of beta-globin gene. Results: Senegal 5'beta-haplotype and the polymorphism at -158 of G(gamma) was (P = 0.063) was linked to the high-HbF phenotype but the (AT)(9)T-5 configuration of the (AT)(x)T-y motif was not (P = 0.6). Study of 30 chromosomes revealed 7 different configurations of the (AT)(x)T-y motif. Association of these motifs with specific beta-globin mutations of this region has also been determined. Conclusion: The senegal haplotype and the polymorphism at -158 of G(gamma) was linked to the high-HbF phenotype.