The CHRNA5-CHRNA3-CHRNB4 gene cluster is of particular interest after our report of association with nicotine dependence (Saccone et al., 2007a) and subsequent evidence of replication in independent samples (Berrettini et al., 2008; Bierut et al., In press; Thorgeirsson et al., 2008). We carried out joint analyses of the two distinct, uncorrelated findings in the CHRNA5-CHRNA3-CHRNB4 cluster, represented by rs16969968 coded recessively and rs578776 coded log-additively to match their best models.
