The anticorrelation with APOE genotype between two closely related endothelial modules prompted us to question whether there may be particular subpopulations within each cell type that are affected differently by allelic variation in APOE. To investigate this possibility, we first used a digital sorting algorithm (DSA) (Zhong et al., 2013) to estimate changes in bulk cell type abundance for the five different cell types by APOE genotype (Figure 3B), and correlated these changes in cell type abundance to amyloid plaque load and tau tangle burden. The gene discussed is APOE; the disease is amyloidosis.