A two-stage genome-wide association study of sporadic amyotrophic lateral sclerosis. por Chiò, A, Schymick, J, Restagno, G, Scholz, S, Lombardo, F, Lai, S, Mora, G, Fung, H, Britton, A, Arepalli, S, Gibbs, JR, Nalls, M, Berger, S, Kwee, L, Oddone, E, Ding, J, Crews, C, Rafferty, I, Washecka, N, Hernandez, D, Ferrucci, L, Bandinelli, S, Guralnik, J, Macciardi, F, Torri, F