1. Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Sahlgrenska University Hospital, Mölndal, Sweden
2. Division of Medical Sciences, Department of Health Sciences, Luleå University of Technology, Luleå, Sweden
3. Capio Artro Clinic, Stockholm, Sweden
4. Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Sahlgrenska University Hospital, Mölndal, Sweden4Department of Molecular Neuroscience, University College London Institute of Neurology, London, United Kingdom