Considering these commonalities, the association between APOE4 with PD and PD-related cognitive impairment has been debated over the years, with discussion that APOE4 may potentially influence AD-type changes that contribute to the development of cognitive changes in PD subjects (Fernández-Calle et al., 2022; Haikal et al., 2024). Here, APOE is linked to Parkinson disease.