1. Department of Neuromuscular Diseases, Barts Health NHS Trust , London E1 1BB , UK
2. Department of Neuromuscular Diseases, University College London , London WC1N 3BG , UK
3. Centre for Neuromuscular Disease, National Hospital for Neurology and Neurosurgery , London WC1N 3BG , UK
4. Department of Neurology and Neurophysiology, Amsterdam Neuroscience, Amsterdam UMC, Location AMC, University of Amsterdam , 1081 HV Amsterdam , The Netherlands
5. Nuffield Department of Clinical Neurosciences, University of Oxford , Oxford OX3 9DU , UK
6. UCL Clinical and Movement Neurosciences Department, National Hospital for Neurology and Neurosurgery, UCL Institute of Neurology , London WC1E 6BT , UK
7. NHS Neuroimmunology and CSF Laboratory, Queen Square Institute of Neurology , London WC1N 3BG , UK