In EA cases with AD, promoter regions of seven genes (DRD5, ADH4, ALDH1A1, CHRNA5, DNMT1, OPRL1, and RGS19) showed hypermethylation in association with CA (Padjust = 0.010–0.048) (Figure 2a and Table S7). Here, OPRL1 is linked to Alzheimer disease.