Genome-Wide Association Analysis of Single-Breath Dl.

Dl 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 could lead to better understanding of the genetic architecture of COPD. We estimated the heritability of Dl 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 in previously reported genome-wide association studies of COPD and related traits. We also characterized associations of known COPD-associated variants and Dl. We estimated the SNP-based heritability of Dl in the European ancestry white population to be 22% ( = 0.0004). We identified three genome-wide significant associations with Dl: variants near , , and loci ( < 5 × 10). In addition, 12 loci were suggestively associated with Dl in European ancestry white ( < 1 × 10 in the combined analysis and  < 0.05 in both COPDGene and GenKOLS), including variants near , , , , , , , , , , , and . Some Dl-associated variants were also associated with COPD, emphysema, and/or spirometric values. Among 25 previously reported COPD loci, , , , and were associated with Dl ( < 0.001). We identified several genetic loci that were significantly associated with Dl and characterized effects of known COPD-associated loci on Dl. These results could lead to better understanding of the heterogeneous nature of COPD.