DPP9 and idiopathic pulmonary fibrosis: Further, we found that IPF cases, regardless of rs12610495 genotype, had significantly higher methylation levels at cg07317664 (slope = 0.030; p <2.2 × 10−16) and significantly lower expression of DPP9 (slope = −0.561; p value = 9.5 × 10−9; Figures 7D and 7E), suggesting that genotype was just one factor contributing to reduced expression in IPF and underscoring the importance of considering epigenetic regulation.