Figure 1. A schematic diagram of potential APOE-related mechanism of Alzheimer’s disease (AD). Blue ovals indicate AD biomarkers. The red rectangle shows the APOE ε4 allele. The purple rounded rectangle indicates cognitive impairment (AD or mild cognitive impairment). Magenta and green rounded rectangles denote the ε4-bearing higher-AD-risk profile (ε4-HRP-AD) and lower-AD-risk profile (ε4-LRP-AD), respectively. The thickness of the arrows denotes tighter (thick lines) and weaker (thin lines) links between genetic variants, AD biomarkers, and cognitive impairment.