Tau acts as an independent genetic risk factor in pathologically proven PD.

"Disclosure statement The authors have no conflicts of interest to declare. All DNA samples were obtained in accordance with the approval of local ethics committees."

"Genotyping of UK replication cases on ImmunoChip was part of the WTCCC2 project, which was funded by the Wellcome Trust (083948/Z/07/Z). UK population control data was made available through WTCCC1. This study was supported by the Medical Research Council and Wellcome Trust Disease Centre (grant WT089698/Z/09/Z). This study was also supported by Parkinson's UK (grants 8047 and J-0804) and the Medical Research Council (G0700943). DNA extraction work that was done in the UK was undertaken at University College London Hospitals, University College, London, who received a proportion of funding from the Department of Health's National Institute for Health Research Biomedical Research Centres funding. This study was supported in part by the Wellcome Trust/Medical Research Council Joint Call in Neurodegeneration award (WT089698) to the Parkinson's Disease Consortium (UKPDC), whose members are from the UCL Institute of Neurology, University of Sheffield, and the Medical Research Council Protein Phosphorylation Unit at the University of Dundee, and an NIHR BRC award to the University of Cambridge/Addenbrooke's Hospital."