1. Division of Congenital Defects, Department of Pediatrics, University of Washington School of Medicine, Seattle, Washington, and Seattle VA Medical Center, Seattle, Washington
2. Department of Neurology, University of Washington School of Medicine, Seattle, Washington, and Seattle VA Medical Center, Seattle, Washington
3. Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, and Departments of Neurology and Pediatrics, University of Pennsylvania, Philadelphia, Pennsylvania