The link between BACE1 and PD is of clinical importance because of the essential role of BACE1 in the generation of toxic Aβ peptides [26], the observed Aβ pathology in PD [3, 4], and the recent association between detectable changes in Aβ levels and clinical features of PD [14, 27–29]. Here, BACE1 is linked to Parkinson disease.