Overlap of Genetic Risk between Interstitial Lung Abnormalities and Idiopathic Pulmonary Fibrosis

Abstract

Rationale Interstitial lung abnormalities (ILA) are associated with the highest genetic risk locus for IPF; however, the extent to which there is additional overlap with IPF, or unique associations among those with ILA is not known. Objectives To perform a genome-wide association study (GWAS) of ILA. Methods: ILA and the subpleural-predominant subtype were assessed on chest computed tomography (CT) scans in the AGES, COPDGene, Framingham Heart, ECLIPSE, MESA, and SPIROMICS studies. We performed a GWAS of ILA in each cohort and combined the results using a meta-analysis. We assessed for overlapping associations in independent GWASs of IPF. Measurements and Main Results Genome-wide genotyping data were available in 1,699 ILA cases and 10,274 controls. The MUC5B promoter variant rs35705950 was significantly associated with both ILA (p=2.6x10-27) and subpleural ILA (p=1.6x10-29). We discovered novel genome-wide associations near IPO11 (rs6886640, p=3.8x10-8) and FCF1P3 (rs73199442, p=4.8x10-8) with ILA, and HTRE1 (rs7744971, p=4.2x10-8) with subpleural-predominant ILA. These novel associations were not associated with IPF. Of 12 previously reported IPF GWAS loci, 5 (DPP9, DSP, FAM13A, IVD, and MUC5B) were significantly associated (p<0.05/12) with ILA. Conclusions In a GWAS of ILA in six studies, we confirmed the association with a MUC5B promoter variant and found strong evidence for an effect of previously described IPF loci; however, novel ILA associations were not associated with IPF. These findings highlight common and suggest distinct genetically-driven biologic pathways between ILA and IPF.