The last region detected by more than one GWAS or meta-GWAS is on chromosome 19q13.2 and includes genes such as CYP2A6/A7/B6, EGLN2, RAB4B, and NUMBL. Thorgeirsson et al.18 identified rs4105144 and rs7937 as significantly associated with CPD in European samples. These two SNPs were reported to be in LD with each other (r2 = 0.32 and D′ = 0.82 in the HapMap CEU samples). Rs4105144 was also in LD with CYP2A6*2 (rs1801272; r2 = 0.13 and D′ = 1.0 in the HapMap CEU samples), which reduces CYP2A6's enzymatic activity.18 The SNP identified by the Tobacco and Genetics Consortium16 (rs3733829) lies between these sites and was reported to show moderate LD with rs4105144 and rs7937. Besides association signals in samples with European ancestry, Kumasaka et al.26 found a copy-number variant (CNV; rs8102683) with a strong effect on CPD (β = −4.00) 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
