1. Department of Medical and Clinical Genetics (L.K., S.M., M.P.), University of Helsinki and Helsinki University Hospital, Finland.
2. Department of Medical Genetics, Turku University Hospital, Finland (S.M.).
3. Northern Finland Laboratory Centre NordLab and Medical Research Centre, Oulu University Hospital and University of Oulu, Finland (H.K.).
4. Department of Pathology, University of Helsinki, Finland (F.Z.).
5. Department of Clinical Neurosciences (A.V.-A.), Helsinki University Hospital and University of Helsinki, Finland.
6. Institute of Biomedicine, University of Turku and Department of Medical Genetics, Turku University Hospital, Finland (J.S.).
7. Department of Clinical Genetics (A.H.H.), Helsinki University Hospital and University of Helsinki, Finland.
8. Neurocenter, Neurology, Kuopio University Hospital, Finland (P.H.).
9. Department of Pathology (L.M.), University of Helsinki and Helsinki University Hospital, Finland.