Finally, fine mapping of a GABAA receptor gene cluster on chromosome 15 reported modest evidence of haplotypic association to ethanol dependence for the GABRG3 gene, encoding the γ3 subunit (Dick et al. 2004). Moreover, Song et al. (2003) showed evidence for imprinting association, with paternal, but not maternal, transmission of GABRA5 and GABRB3 genes, encoding the α5 and β3 subunits, being associated with alcoholism.
