Base editing of an α-globin enhancer to treat β-thalassemia

Gene therapy is the new frontier of medicine, based on modifying the gene material in cells to cure diseases. This strategy comes from the discovery of clustered regularly interspaced short pal-indromic repeats (CRISPR)-Cas system, which has revolutionized the field of molecular biology and medicine. Base editing represents the newest category of this technology, which can directly install point-mutations in cellular DNA without inducing double-strand DNA breaks (DBS). Base editing is used in this project to install transition mutation in the binding sites of the alpha globin genes, to develop a gene therapy approach as a treatment for beta-thalassemic patients. This idea comes from the observation that the co-inheritance of the two different types of thalas-semia turns out as a mild phenotype of the disease. Among the four alpha globin regulatory regions, the second one is the key regulator, and it is composed of four GATA1 binding sites, and two NF-E2 potential binding sites. The use of a Cas9 Nickase coupled with a gRNA targeting specific nucleotides inside the different motif, performing a point mutation is useful to understand which one among these six potential binding sites is criti-cal for the recruitment of the activators of the α-globin expression.