1 The Blizard Institute, Centre for Neuroscience, Surgery & Trauma, Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK; Clinical Board Medicine (Neuroscience), The Royal London Hospital, Barts Health NHS Trust, London, UK. Electronic address: g.giovannoni@qmul.ac.uk.
2 The Blizard Institute, Centre for Neuroscience, Surgery & Trauma, Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK.
3 The University of Newcastle, Australia.
4 Massachusetts General Hospital and Harvard Medical School, Massachusetts, USA.
5 Department of Paediatrics, Dalla Lana School of Public Health, University of Toronto.