[1] UCL Inst Neurol, MRC Ctr Neuromuscular Dis, London, England
[2] UCL Inst Neurol, Acad Neuroradiol Unit, Dept Brain Repair & Rehabil, London, England
[3] UCL Inst Neurol, London, England
[4] Univ Hosp Zurich, Inst Clin Chem, Zurich, Switzerland
[5] Natl Hosp Neurol & Neurosurg, Div Neuropathol, London, England
[6] IRCCS Fdn, Neurol Unit 3, Carlo Besta Neurol Inst, Milan, Italy
[7] Natl Hosp Neurol & Neurosurg, Neurogenet Unit, London, England
[8] Nuffield Dept Clin Neurosci, Oxford, England
[9] Norfolk & Norwich Univ Hosp, Dept Clin Neurophysiol, Norwich, Norfolk, England