The International COPD Genetics Network (ICGN) was a family-based study of COPD at ten centers in North America and Europe [18], [24]. Probands were ages 45–65 with post-bronchodilator FEV1<60% predicted, FEV1/VC<90% predicted, a smoking history of at least 5 pack-years, and at least one sibling with ≥5 pack-year smoking history. Genotyping was performed on Caucasian subjects only (Table 1).
