Analysis of Detailed Phenotype Profiles Reveals CHRNA5-CHRNA3-CHRNB4 Gene Cluster Association With Several Nicotine Dependence Traits

Introduction: The role of the nicotinic acetylcholine receptor gene cluster on chromosome 15q24-25 in the etiology of nico- tine dependence (ND) is still being defined. In this study, we included all 15 tagging single nucleotide polymorphisms (SNPs) within the CHRNA5-CHRNA3-CHRNB4 cluster and tested associations with 30 smoking-related phenotypes. Methods: The study sample was ascertained from the Finnish Twin Cohort study. Twin pairs born 1938-1957 and concor- dant for a history of cigarette smoking were recruited along with their family members (mainly siblings), as part of the Nicotine Addiction Genetics consortium. The study sample consisted of 1,428 individuals (59% males) from 735 families, with mean age 55.6 years.