1. 1 Centre for Neuromuscular Disease, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
2. 2 Department of Neuromuscular Disease, Institute of Neurology, University College London, WC1N 3BG, UK
3. 3 Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
4. 4 Department of Neurology, Erasmus University Medical Center, Rotterdam, The Netherlands
5. 5 Department of Immunology, Erasmus University Medical Center, Rotterdam, The Netherlands
6. 6 Department of Neurology, Hospital de la Santa Creu I Santa Pau, 8025, Barcelona, Spain
7. 7 College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK