In light of the occurrence of Aβ pathology in PD, we sought to determine if genetic variations within five genes involved in APP processing and clearance (ADAM10, BACE1, BACE2, PSEN2, and CLU1) are risk factors for PD in an unselected, population-based cohort of patients with incident PD and age-matched controls. This evidence concerns the gene BACE2 and Parkinson disease.