DPP9 and idiopathic pulmonary fibrosis: Plotting DPP9 expression by rs12610495 genotype confirmed a more robust association of this lead GWAS SNP with expression in IPF cases (slope = −0.212; p value = 1.96 × 10−2 using linear regression of pre-PEER adjusted values) compared with controls (slope = −0.074; p value = 0.526) and was consistent with the G allele being associated with lower DPP9 expression (Figures 5G and 5H).