regulatory influences on expression of genes, suggesting that the highlighted SNP may have a role in regulating nearby genes. Both of the flanking genes have functions relevant for smoking behavior. TRPM4 is a calcium‐activated ion channel involved in many activities including immune response (Guinamard et al. 2010), and is the key gene encoding the channel for most calcium‐activated nonselective cationic currents (I can) observed in native tissues (Mrejeru et al. 2011). I can are involved in the generation of tonic and bursting activity in dopamine neurons (Mrejeru et al. 2011), and the burst firing is proposed to encode a “reward” signal during habit learning and pathological addictions (Phillips et al. 2003). Thus, variants in TRPM4 may affect smoking behavior through the dopaminergic system.
