This is in keeping with previous studies (in cohorts of healthy controls, MCI, and AD) showing PET Aβ burden is strongly associated with APOE genotype, but AD‐PRS beyond the APOE locus explains a low proportion of variance, or effects are non‐significant.41, 57, 58, 59, 60, 61, 62. Here, APOE is linked to Alzheimer disease.