A genome-wide search for loci contributing to smoking and alcoholism

Using the Collaborative Study on the Genetics of Alcoholism (COGA) data, we performed a sib-pair linkage analysis of two smoking-related traits and on e alcoholism phenotype. The first trait, EVRNVR, was a dichotomous one we c onstructed based on epidemiological definitions of smoking. The second trai t, PKYRS, used the quantitative pack-year history provided, and the third t rait was the COGA alcoholism classification, ALDX1. There was some evidence for linkage of the EVRNVR trait to regions on chromosomes 6, 9, and 14. Sm aller numbers of loci provided nominal evidence for linkage to PKYRS, altho ugh some candidate gene regions were identified. The number of loci identif ied using EVRNVR suggests that a threshold-based phenotype may better ident ify loci affecting smoking history. Approximately one-third of the loci tha t showed evidence for linkage to EVRNVR at a nominal significance level (p < 0.01) also showed evidence for linkage to ALDX1. Some of these regions ma y represent loci increasing vulnerability to both smoking and alcoholism. ( C) 1999 Wiley-Liss, Inc.