The effect of SLC6A3 variable number of tandem repeats and methylation levels on individual susceptibility to start tobacco smoking and on the ability of smokers to quit smoking.

Objective: Nicotine acts through the dopamine pathway in the brain affecting reward processing through cigarette consumption. Thus, both genetic and epigenetic factors related to dopamine metabolism may influence individual's smoking behavior.

Materials And Methods: We studied variations of two variable numbers of tandem repeats (VNTRs), 40 and 30 bp in length, in SLC6A3 gene together with six DNA methylation sites located in a first intron of the gene in relation to several smoking-related phenotypes in a study population consisting of 1230 Whites of Russian origin.

The genotypes and methylation of MAO genes as factors behind smoking behavior.

Objective: Smoking dependence is the main cause for tobacco-related illnesses. The addiction-causing substance in tobacco, nicotine, acts through the dopamine pathway in the brain, causing several pleasurable experiences through cigarette smoking. Thus, both genetic and epigenetic factors related to dopamine metabolism may play an important role in influencing an individual's smoking behavior.

Effect of genotype and methylation of CYP2D6 on smoking behaviour.

Objective: Cigarette smoking is one of the most influential environmental factors affecting the DNA methylation patterns. The addiction-causing substance of tobacco smoke, nicotine, has also shown the potential to alter DNA methylation patterns. However, genetics has a strong influence on DNA methylation patterns, which in turn may affect an individual's smoking behaviour.