University of Oxford - Nuffield Department of Clinical Neurosciences, University of Oxford - Nuffield Department of Clinical Neurosciences, University College London - Department of Renal Medicine, University of Amsterdam - Amsterdam Neuroscience, UCL Institute of Neurology - Centre for Neuromuscular Disease, University of Oxford - Nuffield Department of Clinical Neurosciences, UCL Institute of Neurology - Centre for Neuromuscular Disease, Universitat Autònoma de Barcelona - Neuromuscular Diseases Unit, Hospital La Timone - Referral Centre for ALS and Neuromuscular Diseases, Scientific Institute for Research, Hospitalization and Healthcare (IRCCS) - Ospedale Policlinico San Martino, Lund University - Department of Clinical Sciences, University of Leicester - Department of Cardiovascular Sciences, Royal London Hospital - Barts Neuromuscular Diseases Centre, University of Bristol - Institute of Clinical Neurosciences, Gloucestershire Royal Hospital - Department of Neurology, Trinity College - Department of Neurology, UCL Institute of Neurology - Centre for Neuromuscular Disease, UCL Institute of Neurology - Centre for Neuromuscular Disease, Amsterdam UMC - Department of Neurology and Neurophysiology, Amsterdam UMC - Department of Neurology and Neurophysiology, John Radcliffe Hospital - Department of Cellular Pathology, Royal London Hospital - Barts Renal Unit, University College London - Department of Renal Medicine and University of Oxford - Department of Clinical Neurosciences