a key role in dopaminergic neurotransmission (Peall et al., 2013). In addition, polymorphisms within epsilon-sarcoglycan are associated with a psychiatric phenotype consisting of compulsivity, anxiety and alcohol dependence in addition to the characteristic motor phenotype (Hess et al., 2007; Peall et al., 2011). Collectively, these results provide strong functional support for the association of a SNP (rs4770403 p < 10-6) in a regulatory genomic region near SGCG and alcohol dependence (Frank et al., 2012). A functional mechanism is hypothesized whereby genetic variation in SGCG affects GABAergic synaptic transmission within the ventral tegmental area that leads to a hypodopaminergic tone that manifests during protracted abstinence and contributes to craving and compulsive drinking.
