[1] Univ Helsinki, Folkhalsen Inst Genet, Biomedicum, FIN-00290 Helsinki, Finland
[2] Univ Helsinki, Dept Med Genet, Biomedicum, FIN-00290 Helsinki, Finland
[3] Kings Coll London, Randall Div, London SE1 1UL, England
[4] Kings Coll London, Div Cardiovasc, London SE1 1UL, England
[5] ETH Honggerberg, Inst Cell Biol, CH-8093 Zurich, Switzerland
[6] Karolinska Inst, Karolinska Hosp, Dept Clin Neurosci, S-17176 Stockholm, Sweden
[7] Orebro Univ Hosp, Dept Environm Med, S-70185 Orebro, Sweden
[8] Genethon, CNRS, UMR 8115, F-91000 Evry, France
[9] Astrid Lindgren Childrens Hosp, Dept Woman & Child Hlth, Neuropediat Unit, S-17176 Stockholm, Sweden
[10] Vasa Cent Hosp, Dept Neurol, Vaasa 65130, Finland
[11] Tampere Univ Hosp, Dept Neurol, Tampere 33520, Finland