1. Neuromuscular Disorders Unit; Neurology Department; Hospital de la Santa Creu i Sant Pau; Barcelona Spain
2. Medicine Department; Universitat Autònoma de Barcelona (UAB); Barcelona Spain
3. Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER); Valencia Spain
4. Department of Neurology and Neurophysiology; Hospital Universitario Virgen del Rocío; Sevilla Spain
5. Department of Neurology; Hospital Clínico de Santiago; Santiago Spain
6. Department of Neurology; Hospital Universitari Germans Trias i Pujol; Badalona Spain
7. Department of Neurology; Complejo Hospitalario de Navarra; Pamplona Spain