In linkage and candidate gene studies, the most consistent finding has been the involvement of GABA functioning in ∼20 Hz beta oscillatory activity. Porjesz et al. (2002) showed significant linkage between beta oscillations on chromosome 4 and the GABRB1 microsatellite marker, which was overlying a cluster of GABAA receptor genes: GABRG1, GABRA2, GABRA4, and GABRB1. Regional SNP association analysis subsequently pointed to SNPs intronic to GABRA2 as accounting for the signal (Edenberg et al., 2004). GABRA2 was subsequently associated with both beta oscillations and alcohol use disorders (Edenberg et al., 2004; Lydall et al., 2011). Our second aim is to replicate these findings and to investigate how genetic variation in GABRA2 affects expression in brain tissue.
