Gene therapy is a promising therapeutic option for the treatment of inherited blood borne disorders. Our Institution was one of the pioneers in bringing gene therapy for adenosine deaminase deficiency (ADA-SCID) from preclinical studies to clinical applications. Our recent studies allowed us to improve the technology of ADA gene transfer into blood cells and to design more efficient clinical trials. These efforts led to the first demonstration that gene therapy can cure this disease. The goals of our research project are to further improve gene therapy with blood stem cells for ADA-SCID and to better understand the functional properties of gene corrected cells. At the same time we are developing and studying in preclinical models innovative strategies to deliver therapeutic genes into hematopoietic stem cells.