1. From Avigen, Inc, Alameda, CA; the Department of Urology, University of Southern California School of Medicine, Los Angeles, CA; the Departments of Pediatrics, Pathology, and Molecular and Cellular Engineering, University of Pennsylvania School of Medicine, Philadelphia, PA; the Department of Surgery, The Children's Hospital of Philadelphia, Philadelphia, PA; and the Institute for Human Gene Therapy, University of Pennsylvania, Philadelphia, PA.