GABRA2 and alcohol use disorders: no evidence of an association in an Italian case-control study

Alcoholism is a major health and social issue, a highly frequent disease and a cause of premature death. It is also the most expensive addictive disorder being related to high morbidity and mortality, violence, accidents, and social and legal problems. It is a quantitative disorder, where the combined incidence of environmental and multiple genetic factors varies from 1 subject to another. Recent association studies have identified several genes as candidates for alcoholism, including GABAA receptor genes, due to their role in mediating several behavioral effects of alcohol, such as motor incoordination, anxiolysis, sedation, and withdrawal. The proposed association between the 3' half of the gene encoding the alpha-2 subunit of GABA receptor (3'-GABRA2) and alcohol use disorders (AUDs) has received several independent confirmations.

In this study, 10 single nucleotide polymorphisms (SNPs) of the 3'-GABRA2 gene, previously reported to be implicated in alcohol dependence, were used to evaluate the linkage between selected SNPs and AUDs in an Italian sample and to compare findings with those of previous studies.

No evidence of an association was found at the allele, genotype, haplotype, or diplotype levels between the 3'-GABRA2 polymorphisms investigated and alcoholism in 149 Italian alcoholics (98 alcohol dependents and 51 alcohol abusers) and 278 controls.

Despite previous reports, we did not find an association between AUDs and 3'-GABRA2 polymorphisms. This is probably due to the minimal comorbidity of our Italian sample suggesting that this gene is implicated in polysubstance dependence rather than in alcoholism alone.