APOE and Parkinson disease: Of note, whether APOE ε4 increases the risk of vascular dementia (Rohn, 2014), frontotemporal dementia (Verpillat et al., 2002), dementia with Lewy bodies (Lovati et al., 2010), and Parkinson’s disease (Fagan & Pihlstrøm, 2017) is unclear (Lovati et al., 2010).