Enrico Bertini1, Sidney M Gospe2. 1. From the Unit of Neuromuscular and Neurodegenerative Disorders (E.B.), Laboratory of Molecular Medicine, Bambino Gesu' Children's Research Hospital, Rome, Italy; and Departments of Neurology and Pediatrics (S.M.G.), University of Washington, and Division of Neurology, Seattle Children's Hospital, Seattle, WA. 2. From the Unit of Neuromuscular and Neurodegenerative Disorders (E.B.), Laboratory of Molecular Medicine, Bambino Gesu' Children's Research Hospital, Rome, Italy; and Departments of Neurology and Pediatrics (S.M.G.), University of Washington, and Division of Neurology, Seattle Children's Hospital, Seattle, WA. sgospe@uw.edu.