[1] Maastricht Univ, Med Ctr, Dept Neurol, NL-6202 AZ Maastricht, Netherlands
[2] Erasmus MC, Dept Neurol, Rotterdam, Netherlands
[3] Maastricht Univ, Med Ctr, Dept Clin Genet, NL-6202 AZ Maastricht, Netherlands
[4] Tufts Univ, Sch Med, St Elizabeths Med Ctr, Dept Neurol, Boston, MA 02111 USA
[5] Univ Med Ctr, Rudolf Magnus Inst Neurosci, Dept Neurol, Utrecht, Netherlands
[6] Cedars Sinai Med Ctr, Dept Neurol, Los Angeles, CA 90048 USA
[7] Univ Milan, Humanitas Clin Inst, Dept Neurol Sci, Milan, Italy
[8] Hop La Pitie Salpetriere, Dept Neurol, Paris, France
[9] St Luc Univ Hosp, Neuromuscular Reference Ctr UCL St Luc, Brussels, Belgium
[10] Fdn IRCCS Ist Neurol Carlo Besta, Dept Clin Neurosci, Milan, Italy
[11] Toronto Gen Hosp, Dept Neurol, Toronto, ON, Canada
[12] Natl Hosp Neurol & Neurosurg, Ctr Neuromuscular Dis, Dept Neurol, London WC1N 3BG, England
[13] Hop Enfants La Timone, Ctr Reference Malad Neuromusculaires & SLA, Marseille, France
[14] Univ Amsterdam, Acad Med Ctr, Dept Neurol, NL-1105 AZ Amsterdam, Netherlands
[15] Johns Hopkins Sch Med, Dept Neurol, Baltimore, MD USA
[16] London Hlth Sci Ctr, Dept Neurol, London, ON, Canada
[17] Spaarne Hosp, Dept Neurol, Hoofddorp, Netherlands