In the past two years, the most significant findings in addiction genetics have been the involvement of a few nAChR subunit genes specifically in ND and more generally in substance abuse. As illustrated in Box 2, nicotine exerts its biological function by binding to nAChRs, which are composed of five subunits. There are 12 nAChR subunit genes: nine alpha (α2– α10) and three beta (β2–β4) subunits. Variants have been associated with dependence on nicotine, alcohol, and cocaine and with lung cancer susceptibility, as explained below.
