report smoking fewer CPD, less nicotine dependence, and are more likely to quit by themselves [65, 66] (except see [67]) or with pharmacologic treatment [68] (see also [69]). However, relative to variants in other genes, including CHRNA5/CHRNA3, CYP2A6 associations less robustly predict nicotine addiction. For example, a genomewide association study (GWAS) meta-analysis found an association between a variant (rs4105144) in linkage disequilibrium with a metabolically deficient CYP2A6*2 allele (and other reduced activity alleles) and daily cigarette consumption, but not nicotine dependence [52].
