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 and adherence of neutrophils (Jia et al., 2000). Thus, further studies are necessary to determine whether a causal variant is located in GRB14 or GCA or whether the associated SNPs are in linkage disequilibrium with a causal variant located in a nearby gene such as CHRNA1.
