1. Neuromuscular Diseases Unit; Neurology Department; Hospital de la Santa Creu i Sant Pau; Universitat Autònoma de Barcelona; Barcelona Spain
2. Centro para la Investigación Biomédica en Red en Enfermedades Raras (CIBERER); Madrid Spain
3. Service of Neurology and Neuroimmunology; August Pi Sunyer Biomedical Research Institute (IDIBAPS); Hospital Clínic; University of Barcelona; Spain