Hôpitaux Universitaires Paris-Sud-Hôpital Bicêtre, National Referral Centre for Rare Inflammatory Brain and Spinal Diseases, Department of Pediatric Neurology, University Medical Centre, Göttingen, University of Pennsylvania - Perelman School of Medicine, Harvard University - Department of Neurology, University Medical Centre, Göttingen, New York University (NYU) - Neurology, University of California, San Francisco (UCSF) - Weill Institute for Neurosciences, Novartis Pharmaceuticals Corporation, GCE Solutions and Novartis Pharma AG