In light of this, we suggest that although the level of association detected in this study may be due to increased type I errors in multiple comparisons, the BACE1 rs638405 polymorphism is worthy of further investigation in PD, as it provides both a novel genetic link to the observed overlap in the amyloid pathology of PD and AD and increases the number of neurodegenerative diseases that this variant is associated with. The gene discussed is BACE1; the disease is Alzheimer disease.