There are very few human genetic studies examining the role of the CHRNA7 gene with smoking behavior phenotypes. The results from a study of Jewish females indicate that CHRNA7 SNPs are associated with severity of nicotine dependence in females (Greenbaum et al. 2006) but there is no known association of CHRNA7 with smoking cessation (Conti et al. 2008; Ray et al. 2010). In a systems-based genetic study of smoking cessation, 1,295 SNPs in 58 genes within the neuronal nAChR and dopamine systems were investigated for their role in cessation within a bupropion placebo-controlled randomized clinical trial (Conti et al. 2008). A follow-up study on an independent sample of smokers treated with transdermal nicotine also assessed genes involved in acetylcholine synthesis and transport (Ray et al. 2010). Neither study identiWed significant SNPs in the CHRNA7 gene that contributed to smoking cessation phenotypes. However, King et al. (2011) recently reported that, in treatment-seeking smokers randomized to varenicline, CHRNA7 SNP rs6494212 was associated with abstinence.
