1. Department of Pharmacology and Clinical Neuroscience, Umeå University, Sweden
2. Department of Neurology, Helsinki University Central Hospital, Finland
3. Department of Neurology, Danish Headache Centre, Glostrup Hospital, Denmark
4. University of Copenhagen, Denmark
5. Norwegian National Headache Centre, Trondheim University Hospital, Norway
6. Department of Neurosciences, Norwegian University of Science and Technology, Trondheim, Norway
7. Unit of Research, Education and Development, Östersund Hospital, Region Jämtland Härjedalen, Sweden
8. Department of Neurology, Trondheim University Hospital, Norway
9. Institute of Genetics, Folkhälsan Research Center, Finland
10. Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Finland
11. Department of Neurology and FORMI, Oslo University Hospital and University of Oslo, Norway