A GENETIC-BASIS FOR FAMILIAL AGGREGATION IN MULTIPLE-SCLEROSIS par Ebers, G, Sadovnick, A, Risch, N, Bulman, D, Rice, G, Hashimoto, S, Paty, D, Oger, J, Metz, L, Bell, R, Warren, S, Hader, W, Auty, T, Nath, A, Gray, T, Oconnor, P, Nelson, R, Freedman, M, Brunet, D, Paulseth, R, Francis, G, Duquette, P, Murray, T, Bahn, V, Prysephillips, W