Washington University in St. Louis, Washington University in St. Louis - Department of Neurology, University of Utah - Department of Pediatrics, University of Utah - Department of Pediatrics, Mayo Clinic - Department of Neurology and Laboratory Medicine and Pathology and the Center for MS and Autoimmune Neurology, Loma Linda University - Department of Pediatrics, Harvard University - Department of Neurology, Harvard University - Department of Neurology, UCSF Regional Pediatric MS Center, Harvard University - Pediatric Multiple Sclerosis and Related Disorders Program at Boston Children’s Hospital, Washington University Pediatric MS and other Demyelinating Disease Center, Rady Children's Hospital - University of California San Diego Health, University of Texas Southwestern and Children’s Health - Department of Neurology, UCSF Regional Pediatric MS Center, New York University (NYU) - Neurology, Texas Children’s Hospital - Department of Neurology, University of Pennsylvania - Children's Hospital of Philadelphia, Mayo Clinic - Department of Neurology and Laboratory Medicine and Pathology and the Center for MS and Autoimmune Neurology, Cleveland Clinic - Mellen Center for Multiple Sclerosis, Mayo Clinic - Department of Neurology, University of Utah - Department of Neurology, University of Colorado, Aurora - Department of Neurology & Pediatrics, Mayo Clinic - Mayo Clinic Pediatric MS Center, University of Pennsylvania - Children's Hospital of Philadelphia, State University of New York (SUNY) - Department of Neurology, University of Alabama at Birmingham - Department of Nursing, University of California, San Francisco (UCSF) - Weill Institute for Neurosciences, Mayo Clinic - Department of Neurology and Laboratory Medicine and Pathology and the Center for MS and Autoimmune Neurology and Independent