There are potential candidate genes within the support interval of the locus reported here. For example, the nicotinic acetylcholine α1 gene (CHRNA1) is located near the center of the reported linkage peak. Although originally thought to be found only in muscle tissue, recent gene expression studies have found this gene to be expressed in brain as well (Su et al., 2004) suggesting a potential role in nicotine addiction. Evidence for an association between this gene and smoking behavior has been previously reported (Faraone et al., 2004), but negative findings have also been described (Sherva et al., 2008). In addition, SNPs located in the nearby growth factor receptor-bound protein 14 (GRB14) and grancalcin (GCA) genes were recently associated with nicotine dependence in a genome-wide association study (GWAS) (Vink et al., 2009). Potential mechanisms through which one or both of these genes might confer risk to nicotine dependence are not clear. GRB14 is thought to be involved in insulin receptor signaling and may influence signaling pathways that regulate growth and metabolism (Carre et al., 2008). GCA may be involved in the migration
