Leukocyte DNA methylation in Alzheimer´s disease associated genes: replication of findings from neuronal cells.

Differences in gene-wide DNA methylation of the Alzheimer's disease (AD)-associated genes , and are reported to be associated with AD in post-mortem brain samples. We investigated whether the same associations could be found in leukocytes collected pre-mortem. Using cohort data of 544 Swedish twins (204 dementia diagnoses), we replicated the findings in and at < 0.05. However, co-twin control analyses indicated that the associations were partly explained by familial confounding. Thus, DNA methylation differences in and are present in both neuronal cells and leukocytes, and not fully explained familial factors.