1. Service de Neurologie A and the European Database for Multiple Sclerosis Coordinating Center, Hôpital Neurologique Pierre Wertheimer, Hospices Civils de Lyon, 59 boulevard Pinel, Lyon, F-69677, France,
2. Unité INSERM U842, Université de Lyon, Lyon 1, UMR-S 842, France
3. Service de Neurologie A and EDMUS Coordinating Center, Hôpital Neurologique Pierre Wertheimer, Hospices Civils de Lyon, Lyon, F-69677, France