In a sample of treatment-seeking smokers and an independent sample of family-based non-treatment seekers consisting of either African-Americans or European Americans, significant ChAT SNP and haplotype associations were identified for multiple measures of nicotine dependence (Ray et al. 2010; Wei et al. 2010). With respect to smoking cessation, Ray and colleagues performed a systems-based genetic association analysis in a discovery sample of 472 treatment-seeking smokers of European ancestry, assessing smoking relapse following 8 weeks of transdermal nicotine therapy. A cluster of SNPs in ChAT haplotype block 6 was significantly associated with relapse (Ray et al. 2010). These results are consistent with Heitjan et al. (2008) who found that ChAT SNP rs1917810 in haplotype 6 was associated with response to bupropion and smokers with the minor allele had higher abstinence rates on placebo.
