We previously carried out a high-density association study covering the complete family of 16 CHRN genes in European-ancestry subjects from the United States and Australia (Saccone et al., 2009a). Evidence for association was observed not only for CHRNA5-CHRNA3-CHRNB4, but also for the CHRNB3-CHRNA6, CHRND-CHRNG, CHRNA4 and CHRNB1 genes. This evidence nominates additional CHRN genes in the development of nicotine dependence.
