APOE and Alzheimer disease: In a UK‐Biobank sub‐sample (mean age = 64, range = 45–81 years), we associate WMHV with (1) AD‐PRS estimated via SNPs across the genome (minus apolipoprotein E [APOE] locus) and (2) AD‐PRS estimated with SNPs proximal to specific genes that are overexpressed in cerebrovascular cell species.