Smoking and Genetics

Tobacco smoking is a complex phenotype that is directly associated with early death and morbidity. The genetic and environmental factors affecting several smoking-related phenotypes have been studied in many different designs including family, twin, and genome-wide association studies. In this regard it may be the best studied substance use disorder; however, while overall heritability for several smoking phenotypes seem to be moderately high, the function of discovered genetic variants remains largely unexplored. Several studies indicate that genetic variation in and around nicotinic acetylcholine receptor subunits and CYP2A6, involved in nicotine catabolism, are strongly associated with several smoking phenotypes, while other discovered variants implicate dopamine, glycogenesis, and epigenetic gene regulation. This chapter explores current knowledge of genetics of smoking behavior phenotypes and future perspectives.