This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ; Background . Parkinson’s disease (PD) and Alzheimer’s disease (AD) share pathological features, including amyloid-beta pathology. Amyloid-beta peptide is generated by sequential proteolysis of amyloid precursor protein (APP), and genetic variations in the processing pathway genes have been found to increase the risk of AD; however, the contribution in PD is unknown. Methods . The aim of this study was to investigate whether candidate polymorphisms in five genes ( ADAM10 , BACE1 , BACE2 , PSEN2 ,and CLU ) involved in the APP processing pathway affect PD risk in a population-based cohort of patients with incident PD and control subjects from the Norwegian ParkWest study. Results .Wefoundanassociationofrs638405in BACE1 with increased risk of PD, thus providing a novel link, at the genetic level, between amyloid-beta pathology and PD.