[1] Queens Univ Belfast, Sch Pharm, McClay Res Ctr, Cytokine Biol & Genet Programme, Belfast, Antrim, North Ireland
[2] Queens Univ Belfast, Dept Med Genet, Belfast, Antrim, North Ireland
[3] Univ Louvain, Univ Hosp Gasthuisberg, Rega Inst Med Res, Louvain, Belgium
[4] Univ Louvain, Univ Hosp Gasthuisberg, Dept Neurol, Louvain, Belgium
[5] Royal Victoria Hosp, Dept Neurol, Belfast BT12 6BA, Antrim, North Ireland