Genome-wide association analysis of single-breath DL <inf>CO</inf>

Abstract

Copyright © 2019 by the American Thoracic Society DL CO is a widely used pulmonary function test in clinical practice and a particularly useful measure for assessing patients with chronic obstructive pulmonary disease (COPD). We hypothesized that elucidating genetic determinants of DL CO could lead to better understanding of the genetic architecture of COPD. We estimated the heritability of DL CO using common genetic variants and performed genome-wide association analyses in four cohorts enriched for subjects with COPD (COPDGene [Genetic Epidemiology of COPD], NETT [National Emphysema Treatment Trial], GenKOLS [Genetics of Chronic Obstructive Lung Disease study], and TESRA [Treatment of Emphysema With a Gamma-Selective Retinoid Agonist study]) using a combined European ancestry white dataset and a COPDGene African American dataset. We assessed our genome-wide significant and suggestive associations for DL CO in previously reported genome-wide association studies of COPD and related traits. We also characterized associations of known COPD-associated variants and DL CO . We estimated the SNP-based heritability of DL CO in the European ancestry white population to be 22% (P = 0.0004). We identified three genome-wide significant associations with DL CO : variants near TGFB2, CHRNA3, and PDE11A loci (P, 5 3 10 28 ). In addition, 12 loci were suggestively associated with DL CO in European ancestry white (P, 1 3 10 25 in the combined analysis and P, 0.05 in both COPDGene and GenKOLS), including variants near NEGR1, CADM2, PCDH7, RETREG1, DACT2, NRG1, ANKRD18A, KRT86, NTN4, ARHGAP28, INSR, and PCBP3. Some DL CO -associated variants were also associated with COPD, emphysema, and/or spirometric values. Among 25 previously reported COPD loci, TGFB2, CHRNA3/CHRNA5, FAM13A, DSP, and CYP2A6 were associated with DL CO (P, 0.001). We identified several genetic loci that were significantly associated with DL CO and characterized effects of known COPD-associated loci on DL CO . These results could lead to better understanding of the heterogeneous nature of COPD.