The other flanking gene, SLC6A16, is a member of the Na+/Cl− dependent neurotransmitter transporter gene family (Farmer et al. 2000), and little is known about its substrates and functional significance. Another member of the solute carrier gene group, SLC17A7, located 211 kb from rs73050610, is a vesicular glutamate transporter previously found to be induced by smoking (Flatscher‐Bader et al. 2008). Blockade of glutamatergic transmission inhibits the rewarding‐enhancing effects of nicotine, thus reducing nicotine‐seeking behavior (Li et al. 2014). Alterations in glutamatergic neurotransmission are involved in several psychiatric disorders, such as schizophrenia and alcohol dependence (Shigeri et al. 2004; Comasco et al. 2014), which also influence smoking behavior; however, in this study we did not assess comorbid psychiatric disorders. Inclusion of such phenotypes in future studies would allow scrutiny of potential pleiotropic effects.
