From the Service de Neurologie (A.G., F.R., R.C., S.V.), Sclérose en Plaques, Pathologies de La Myéline et Neuro-inflammation, Hôpital Neurologique Pierre-Wertheimer, Hospices Civils de Lyon, Bron; Université de Lyon (A.G., M.R., F.S.), Université Claude Bernard Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Évolutive UMR 5558, Villeurbanne; Service de Biostatistique-Bioinformatique (A.G., M.R., F.S.), Hospices Civils de Lyon; Université de Lyon (F.R., R.C., S.V.), Université Claude Bernard Lyon 1; Observatoire Français de La Sclérose en Plaques (F.R., R.C., S.V.), Centre de Recherche en Neurosciences de Lyon, INSERM 1028 et CNRS UMR; EUGENE DEVIC EDMUS Foundation Against Multiple Sclerosis (F.R., R.C., S.V.), State-approved Foundation, Bron; Nancy University Hospital (M.D.), Department of Neurology, Université de Lorraine, APEMAC; CHU Pontchaillou (E.L.P.), CIC1414 INSERM, Rennes; CHU de Toulouse (J.C.), Hôpital Pierre-Paul Riquet, Department of Neurology, CRC-SEP, Toulouse; Infinity (J.C.), INSERM UMR1291–CNRS UMR5051, Université Toulouse III; CHU de Strasbourg (J.D.S.), Department of Neurology and Clinical Investigation Center, CIC 1434, INSERM 1434; Univ. Bordeaux (A.R.), F-33000 Bordeaux INSERM U1215, Neurocentre Magendie, F-33000 Bordeaux CHU de Bordeaux, Department of Neurology, CIC Bordeaux CIC1401; Département de Neurologie (E.M.), Hôpital Pitié-Salpêtrière, APHP, Paris; Centre de Ressources et de Compétences SEP Paris (E.M.); CHU de Montpellier (P.L.), MS Unit; University of Montpellier (MUSE) (P.L.); CHU Lille (H.Z.), CRCSEP Lille, Univ Lille, U1172; Fondation Rotschild (C. Papeix), Department of Neurology, Paris; CHU de Caen (G.D.), MS Expert Centre, Department of Neurology, Avenue de La Côte-de-Nacre, Normandy University, Caen; Neurology (C.L.-F.), UR2CA, Centre Hospitalier Universitaire Pasteur2, Université Nice Côte d'Azur, Nice; CHU de Dijon (T.M.), Department of Neurology, EA4184; CHU de Nantes (D.A.L.), Service de Neurologie & CIC015 INSERM; CRTI-Inserm U1064 (D.A.L.), Nantes; CHU de Besançon (E.B.), Service de Neurologie; Sorbonne Universités (B.S.), UPMC Paris 06, Brain and Spine Institute, ICM, Hôpital de La Pitié Salpêtrière, Inserm UMR S 1127, CNRS UMR 7225, and Department of Neurology, AP-HP, Saint-Antoine Hospital; CHU Clermont-Ferrand (Pierre Clavelou), Department of Neurology, F-63000 Clermont-Ferrand Université Clermont Auvergne, Inserm, Neuro-Dol, F-63000 Clermont-Ferrand; Department of Neurology (E.T.), Nimes University Hospital; Institut de Génomique Fonctionnelle (E.T.), UMR5203, INSERM 1191, Univ. Montpellier; Hôpital de Poissy (O.H.), Department of Neurology; Aix Marseille Univ (J.P.), APHM, Hôpital de La Timone, Pôle de Neurosciences Cliniques, Service de Neurologie; CHU d'Amiens (A.A.K.), Department of Neurology; CHU Grenoble Alpes (O.C.), Department of Neurology, La Tronche/Grenoble; CHU de Rouen (B.B.), Department of Neurology; CHU de La Martinique (Philippe Cabre), Department of Neurology, Fort-de-France; APHP (A.W.), Hôpital Henri Mondor, Department of Neurology, Créteil; CHU de Limoges (L.M.), Hôpital Dupuytren, Department of Neurology; CHU de Saint-Étienne (J.-P.C.), Hôpital Nord, Department of Neurology; CHU de Tours (A.M.), Hôpital Bretonneau, CRC SEP and Department of Neurology; CHU de Reims (S.M.), CRC-SEP, Department of Neurology; Hôpital Sud Francilien (N.H.B.), Department of Neurology, Corbeil Essonnes; CHU Bicêtre (D.D.B.), Department of Neurology, Le Kremlin Bicêtre; Department of Neurology (K.H.), Hôpital Pierre Delafontaine, Centre Hospitalier de Saint-Denis; CHU La Milétrie (J.-P.N.), Hôpital Jean Bernard, Department of Neurology, Poitiers; CH de Pontoise (C. Pottier), Hôpital René Dubos, Department of Neurology; and Centre Hospitalier de Versailles (C.N.), Department of Neurology, F-78150 Le Chesnay, France.