A whole genome association study in multiple sclerosis patients from north Portugal. by Martins Silva, B, Thorlacius, T, Benediktsson, K, Pereira, C, Fossdal, R, Jonsson, H, Silva, A, Leite, I, Cerqueira, J, Costa, P, Marta, M, Foltynie, T, Sawcer, S, Compston, A, Jonasdottir, A