1. Departments of Pediatrics and Neurology Children's Hospital of Philadelphia Perelman School of Medicine University of Pennsylvania Philadelphia Pennsylvania 19104
2. Department of Neurology University of California Los Angeles Los Angeles California
3. Department of Neurology Emory University Atlanta Georgia
4. Department of Neurology University of Chicago Chicago Illinois
5. Department of Neurology University of Iowa Iowa City Iowa
6. Division of Clinical and Metabolic Genetics The Hospital for Sick Children University of Toronto Toronto Ontario Canada
7. Department of Neurology University of South Florida Tampa Florida
8. Department of Neurology The Ohio State University Columbus Ohio
9. Department of Neurology University of Florida Gainesville Florida
10. Department of Neurology University of Rochester Rochester New York
11. Department of Pathology and Lab Medicine Perelman School of Medicine University of Pennsylvania Philadelphia Pennsylvania 19104