We also noted novel genome-wide significant signals of association with smoking behaviour in NOL4L, LPPR5, and DNAH8 (table 2, appendix pp 110–112). A SNP in C20orf203, near to NOL4L, but independent of our sentinel variant, has previously been implicated in nicotine dependence.45 We identified secondary independent signals, which did not reach genome-wide significance, at three of the loci associated with smoking behaviour (appendix pp 56–57, 99–101),46 including a novel rare (MAF=0·09%) intergenic SNP near NCAM1. For novel signals for smoking behaviour, we did a meta-analysis of summary statistics from two previous, less powerful studies17,19 and found corroborative evidence for NCAM1, TEX41/PABPC1P2, and NOL4L (eg, for smoking initiation p=0·0003, p=0·017, and p=0·0006, respectively; appendix pp 24, 83–84). We identified a further eight loci with suggestive (5 × 10−8<p<5 × 10−7) evidence of association with smoking behaviour (appendix p 72–73), including CHRNA4 at 20q13.33 (p=1·01 × 10−7).47
