A novel δβ fusion gene expresses hemoglobin A (HbA) not Hb Lepore:: Senegalese δ0β+ thalassemia

This study identified and characterized a novel delta beta fusion gene in which the delta -globin gene promoter is linked to intact beta -globin coding sequences in a Senegalese family. It results from a 7.4-kb deletion that removes the delta -globin coding sequences, the delta beta intergenic region as well as the beta -globin gene promoter and causes delta (0)beta (+) thalassemia with hemoglobin A expressed at the 11% to 15% range. The phenotype of this naturally occurring delta beta hybrid gene not only clarifies, in an in vivo context, the respective strength of delta- and beta -globin gene promoters, but also emphasizes the importance of P-globin intragenic sequences in the expression of beta -globin chains.