Carol Miao         Children's Hospital and Regional Medical Center      Andrew Brayman         Senior Research Scientist         Center for Medical & Industrial Ultrasound         Applied Physics Laboratory         University of Washington	Non viral gene transfer offers a safer alternative to viral gene delivery in the treatment of hemophilia. Although viral gene transfer has shown promise in the treatment of several diseases, including hemophilia, the obstacles associated with it remain: 1) the difficulty of large-scale virus production; 2) host immune responses; 3) possible toxicity of the encapsulated virus; and 4) the possible creation of tumors in the host genome. Recently, University of Washington researchers have developed liver-specific expression cassettes that can produce therapeutic level and persistent factor IX gene expression in mouse livers after naked DNA transfer. This multidisciplinary study explores the development of different non-viral delivery pathways to efficiently transfer factor IX as well as factor VIII gene expression cassettes into liver. These transfer strategies are being tested for efficacy and duration of the phenotype in hemophilia B and A mouse models.