Further, we found that IPF cases, regardless of rs12610495 genotype, had significantly higher methylation levels at cg07317664 (slope = 0.0304, p-value < 2.2 × 10−16) and significantly lower expression of DPP9 (slope = −0.561, p-value = 9.5 × 10−9; Fig 7D–E), suggesting that genotype was just one factor contributing to reduced expression in IPF and underscoring the importance of considering epigenetic regulation. This evidence concerns the gene DPP9 and idiopathic pulmonary fibrosis.