We tested a fourth locus representing rs12914008, a relatively uncommon (MAF ∼5%) non-synonymous SNP in CHRNB4 that has previously shown suggestive evidence for association in European-Americans [4]. In both the univariate analysis and the joint analysis with locus 1, locus 4 is not associated with smoking behavior after multiple test correction. Because of the low allele frequency of this variant, the power to detect an effect is lower than for the other three loci.
