DNMT3A and Alzheimer disease: DNA methylation by DNMT1 or DNMT3A enzymes has been broadly implicated in neural development and differentiation (Takizawa et al, 2001; Wu et al, 2010, 2012) as well, but here we aim to validate whether DNA methylation regulates oligodendrocyte differentiation genes in the 242-gene subnetwork disrupted in AD and HD.