1. Institute of Clinical Medicine-Neurology, University of Eastern Finland, and Department of Neurology, Kuopio University Hospital, FI-70211 Kuopio, Finland
2. Department of Anatomy and Cell Biology, Institute of Biomedicine, University of Oulu, FI-90014 Oulu, Finland
3. Biocenter Oulu, University of Oulu, FI-90014 Oulu, Finland
4. Neuropsychiatric Genetics Group, Department of Vertebrate Genomics, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
5. Genetics and Aging Research Unit, Massachusetts General Hospital, Charlestown, and Harvard Medical School, Boston, Massachusetts 02129