1 Department of Neurology and Neurophysiology, Karolinska University Hospital, Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden.
2 Neuromuscular Centre and Clinical Genetics, Sahlgrehnska University Hospital, Gothenburg, Sweden.
3 Department of Neurology, Örebro University Hospital, Örebro, Sweden.
4 Department of Pharmacoepidemiology, Karolinska Institute, Stockholm, Sweden.
5 Karolinska University Hospital, Centre for Inherited Metabolic Diseases, Stockholm, Sweden.