The deCODE project offers a preview of things to come.2 In this study the genomes of close to 11 000 Icelandic smokers were interrogated with a platform displaying over 306 000 single-nucleotide polymorphisms. The report shows that a cluster containing the α3, α5 and β4 gene subunits of the nicotinic acetylcholine receptor (nAChR) had a strong effect on nicotine dependence and the risk of lung cancer and peripheral arterial disease. Moreover, the frequency of the variant increases with addiction severity (addiction here is used interchangeably with the term dependence as per DSM IV).4
