GABRA2 and alcohol drinking: In this respect, a comparison of the results of GWAS with that of the first-generation genetic studies on alcoholism (linkage and candidate gene studies) which emphasize genes involved in alcohol metabolism—e.g., alcohol-dehydrogenase (ADH) gene cluster [79] or genes coding targets of alcohol pharmacodynamic activity—e.g., GABRA2 (GABA-A receptor subunit α-2) [80] is very characteristic.