In the group without AD-tau and AGD-tau pathology, APOE4 was significantly associated with higher levels of soluble, detergent-soluble, and insoluble Aβ42 compared to APOE3 (TBS: β = 2.68, p < 0.001; TBSX: β = 2.18, p = 0.002; FA: β = 21.79, p = 0.006). This evidence concerns the gene APOE and Alzheimer disease.