in a Japanese population and another significantly associated SNP (rs11878604; β = −2.69) located 30 kb downstream of the CYP2A6 gene after adjustment of the CNV. Rs8102683 shared a deletion region with other CNVs ranging from the 3′ end of the CYP2A6 gene to the 3′ end of the CYP2A7 gene; however, this common deletion was not significant in a European population.26 Very recently, Loukola et al.130 conducted the first GWAS on nicotine metabolite ratio (NMR) and identified 719 GWS SNPs within this region. Strikingly, the significant CYP2A6 variants explain a large fraction of variance (up to 31%) in NMR in their sample.
