ELOVL2 and Alzheimer disease: By intersecting these 23 CpGs with the 1846 CpGs significantly associated with both aging and AD described above, we identified 9 CpGs, located in the promoter regions of PDE1B, ELOVL2, PODXL2 genes and other genomic regions, that showed both strong concordance in brain-to-blood DNAm levels, as well as association with AD diagnosis or AD neuropathology in independent studies (Supplementary Table 11).