Results for markers in the GABAA receptor gene cluster on chromosome 5 are still controversial, with associations reported in some samples, but not others (Dick et al. 2005; Sander et al. 1999; Song et al. 2003). Thus, a positive association between ethanol dependence and SNPs at the GABRG2 gene, encoding for the γ2 subunit, was observed in Scottish (Loh et al. 1999), Finnish (Radel et al. 2005), and Japanese populations (Loh et al. 2000). Association with the GABRB2 gene, encoding for the β2 subunit, was reported in Scottish (Loh et al. 1999), Finnish, and Southwestern Native American (Radel et al. 2005) populations. The GABRA1 gene, encoding for the α1 subunit, was associated with several drinking behavior phenotypes, including history of blackouts, age at first drunkenness, level of response to ethanol, and ethanol dependence (Dick et al. 2006). Associations with the GABRA6, encoding for the α6 subunit, have been found in Scottish (Loh et al. 1999) and Finnish (Radel et al. 2005) populations. Furthermore, sons of alcoholics with the proline385 to serine polymorphism at GABRA6 were less sensitive to the effects
