1. Department of Neurology; Washington University School of Medicine in Saint Louis; St. Louis Missouri 63110 USA
2. Department of Pediatrics; Washington University School of Medicine in Saint Louis; St. Louis Missouri USA
3. Department of Pediatrics; The Ohio State University and Center for Gene Therapy; Nationwide Children's Hospital Columbus Ohio USA
4. Division of Biostatistics; Washington University School of Medicine in Saint Louis; St. Louis Missouri USA
5. Department Physical Medicine and Rehabilitation; University of California; Davis Medical Center Sacramento California USA
6. Department of Neurology; University of Minnesota; Minneapolis Minnesota USA
7. Department of Neurology; Stanford University; Stanford California USA
8. Department of Neurology; Harvard University; Boston Children's Hospital Boston Massachusetts USA
9. Department of Neurology; University of Florida College of Medicine; Gainesville Florida USA