Each of the three Finnish cohorts independently showed genome-wide significant association on 19q13.2. In our GWAS meta-analysis 719 SNPs exceeded the genome-wide significance threshold within a 4.2 Mb region on 19q13.2 (chr19:39546965–43710562; according to GRCh37/hg19) (S2 Table). Manhattan and QQ plots are presented in Figs 1 and 2. The strongest evidence for association emerged for CYP2A6 (minimum p = 5.77E-86 for rs56113850, in intron 4) (S3 Table). Other genes of relevance with genome-wide significant signals included CYP2B6 (minimum p = 1.95E-24 for rs7260329, in intron 8), CYP2A7 (ENSG00000198077) (minimum p = 1.43E-38 for rs28602288, beta = -0.48, -83C>T, within predicted promoter region), EGLN2 (ENSG00000269858) (minimum p = 7.87E-16 for rs76443752, in intron 3), and NUMBL (ENSG00000105245) (minimum p = 1.40E-20 for rs4802082, in intron 5) (S2 Table).
