Several additional SNPs were later analyzed in the CHRNA3/5 region in the Bergen and ICGN populations (Table S2). One non-synonymous polymorphism in CHRNA5 (rs16969968) which coded for the substitution of an asparagine for an aspartic acid at amino acid 398) was associated with COPD in the Bergen (p = 8.8×10−4) and ICGN (p = 2.78×10−6) cohorts (combined p value 5.08×10−8). Since this SNP showed a weaker association than both rs8034191 and rs1051730 it was not considered as a causal variant.
