The PMC is particularly susceptible to early amyloid (Aβ) plaque deposition, one of the hallmark pathologic features of AD (Buckner et al., 2005; Maass et al., 2019; Palmqvist et al., 2017), with APOE E4 allele carriers having both a younger age of onset and faster rates of PMC amyloid deposition relative to non-carriers (Burnham et al., 2020; Mishra et al., 2018). Here, APOE is linked to Alzheimer disease.