1. Department of Human Genetics; Leiden University Medical Center; Leiden, The Netherlands
2. Department of Neurology; University of Rochester Medical Center; Rochester, NY USA
3. Department of Neurology; Radboud University; Nijmegen Medical Center; Nijmegen, The Netherlands
4. Department of Biological Chemistry; School of Medicine; University of California; Irvine, CA USA
5. Division of Human Biology; Fred Hutchinson Cancer Research Center; Seattle, WA USA