Phenotypic and genetic heterogeneity among subjects with mild airflow obstruction in COPDGene

Academic Article

Abstract

  • © 2014 Elsevier Ltd. All rights reserved. Background Chronic obstructive pulmonary disease (COPD) is characterized by marked phenotypic heterogeneity. Most previous studies have focused on COPD subjects with FEV 1 < 80% predicted. We investigated the clinical and genetic heterogeneity in subjects with mild airflow limitation in spirometry grade 1 defined by the Global Initiative for chronic Obstructive Lung Disease (GOLD 1). Methods Data from current and former smokers participating in the COPDGene Study (NCT00608764) were analyzed. K-means clustering was performed to explore subtypes within 794 GOLD 1 subjects. For all subjects with GOLD 1 and with each cluster, a genome-wide association study and candidate gene testing were performed using smokers with normal lung function as a control group. Combinations of COPD genome-wide significant single nucleotide polymorphisms (SNPs) were tested for association with FEV 1 (% predicted) in GOLD 1 and in a combined group of GOLD 1 and smoking control subjects. Results K-means clustering of GOLD 1 subjects identified putative "near-normal", "airway-predominant", "emphysema-predominant" and "lowest FEV 1 % predicted" subtypes. In non-Hispanic whites, the only SNP nominally associated with GOLD 1 status relative to smoking controls was rs7671167 (FAM13A) in logistic regression models with adjustment for age, sex, pack-years of smoking, and genetic ancestry. The emphysema-predominant GOLD 1 cluster was nominally associated with rs7671167 (FAM13A) and rs161976 (BICD1). The lowest FEV 1 % predicted cluster was nominally associated with rs1980057 (HHIP) and rs1051730 (CHRNA3). Combinations of COPD genome-wide significant SNPs were associated with FEV 1 (% predicted) in a combined group of GOLD 1 and smoking control subjects. Conclusions Our results indicate that GOLD 1 subjects show substantial clinical heterogeneity, which is at least partially related to genetic heterogeneity.
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    Author List

  • Lee JH; Cho MH; McDonald MLN; Hersh CP; Castaldi PJ; Crapo JD; Wan ES; Dy JG; Chang Y; Regan EA
  • Start Page

  • 1469
  • End Page

  • 1480
  • Volume

  • 108
  • Issue

  • 10