The disrupted methylation patterns in blood DNA and rectal biopsies of UC patients at diagnosis and during course of the disease. (A) In blood, DNAm differences observed between IBD cases and controls (x-axis) reverted back to normal after treatment (Gastroenterology, 2019, 156 (8): 2254–2265), evidenced by a strong negative correlation in case-control effect sizes (x-axis) and baseline-follow-up differences (y-axis; R=-0.93; P < 2.2e-16 (B) In contrast, the majority (1828) of the 2446 CpGs showing case-control differences in rectal biopsies at baseline did not show even nominally significant differences between baseline and follow-up in cases, suggesting that they persist during treatment and over the course of disease.