RWTH Aachen University - Department of Neurology, Forschungszentrum Jülich GmbH - ARA-BRAIN Institute Molecular Neuroscience and Neuroimaging, RWTH Aachen University - Department of Medical Statistics, UCL - Queen Square Institute of Neurology - Ataxia Centre, Fondazione IRCCS Istituto Neurologico ‘Carlo Besta’ - Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico ‘Carlo Besta’ - Unit of Medical Genetics and Neurogenetics, Hôpital de la Pitié-Salpêtrière - Sorbonne Université, Paris Brain Institute (ICM Institut du Cerveau), Hôpital de la Pitié-Salpêtrière - Sorbonne Université, Paris Brain Institute (ICM Institut du Cerveau), Medical University of Innsbruck - Department of Neurology, Medical University of Innsbruck - Department of Neurology, Ludwig Maximilian University of Munich (LMU) - The Friedrich-Baur-Institute, Ludwig Maximilian University of Munich (LMU) - The Friedrich-Baur-Institute, La Paz Institute for Health Research (IdiPAZ) - Reference Unit of Hereditary Ataxias and Paraplegias, University of Tübingen - Department of Neurology and Hertie-Institute for Clinical Brain Research, University of Tübingen - Department of Neurology and Hertie-Institute for Clinical Brain Research, University Hospital Bonn (UKB) - Department of Neurology, University Hospital Bonn (UKB) - Department of Neurology, RWTH Aachen University - Department of Neurology, Université Libre de Bruxelles (ULB) - Laboratory of Experimental Neurology, Université Libre de Bruxelles (ULB) - Laboratory of Experimental Neurology, RWTH Aachen University - Department of Neurology and Independent