1. Mass General Hospital; 275 Charles St./Warren 310 Boston Massachusetts USA MA 02114
2. National Hospital for Neurology and Neurosurgery; Department of Neurology and MRC Centre for Neuromuscular Diseases; Queen Square London UK WC1N 3BG
3. National Hospital for Neurology and Neurosurgery; MRC Centre for Neuromuscular Diseases; PO Box 114 Queen Square London UK WC1N 3BG
4. Academic Medical Centre, University of Amsterdam; Department of Neurology; Meibergdreef 9 PO Box 22700 Amsterdam Netherlands 1100 DE
5. London School of Hygiene & Tropical Medicine; Department of Medical Statistics; Keppel Street London UK WC1E 7HT
6. McGill University; Department of Neurology & Neurosurgery; Montreal General Hospital - Room L7-313 1650 Cedar Avenue Montreal QC Canada H3G 1A4