[1] Leiden Univ, Med Ctr, Dept Neurol, NL-2300 RC Leiden, Netherlands
[2] John Radcliffe Hosp, Weatherall Inst Mol Med, Dept Neurosci, Oxford OX3 9DS, England
[3] Univ Barcelona, Hosp Clin, Serv Neurol, E-08036 Barcelona, Spain
[4] Leiden Univ, Med Ctr, Ctr Human & Clin Genet, NL-2333 AL Leiden, Netherlands
[5] Univ Hosp Maastricht, Dept Neurol, NL-6202 AZ Maastricht, Netherlands