Regions of differential methylation following folate metabolism perturbations. (A) Comparisons of MTHFR 677CC vs. 677TT genotypes and effect of folic acid supplementation in (B) 677CC or (C) 677TT participants were examined: left panels—total DMCs, isolated single CpG sites, and merged regions obtained after neighboring DMCs found within were merged; right panels—size distribution of merged regions. Note: CpG, 5′-cytosine-phosphate-guanine-3′; DMCs, differentially methylated cytosines; MTHFR, methylenetetrahydrofolate reductase.