Little current data indicates which specific genes contain variants that are likely to contribute to vulnerability to nicotine dependence and/or to success in abstaining from nicotine in formerly-dependent individuals. Linkage based genome scans for nicotine dependence, age of smoking onset and other nicotine dependence related phenotypes (see discussion) have identified a number of linkage peaks [12-20]. The most prominent linkage peaks from these efforts largely differ from sample to sample, however.
