In this study, we sought to assess if ATP13A2 levels in Lewy body disease are modified by Alzheimer-type β-amyloid deposition by evaluating cases of pure PD that lack β-amyloid-positive plaques and pure dementia with Lewy bodies (DLB) and also β-amyloid-positive plaques. The gene discussed is ATP13A2; the disease is Lewy body dementia.