1. Department of Neurology; Leiden University Medical Center; Leiden The Netherlands
2. Department of Neurology; University of Bern; Bern Switzerland
3. Swiss Huntington Center; Gümligen Switzerland
4. George Huntington Institute; Muenster Germany
5. Department of Radiology; University of Muenster; Muenster Germany
6. Department of Neurodegenerative Diseases and Hertie-Institute for Clinical Brain Research; University of Tuebingen; Tuebingen Germany