Association of genetic variants in alcohol dehydrogenase 4 with alcohol dependence in Brazilian patients

Objective: The authors evaluated the association of three functional promoter polymorphisms of the ADH4 gene with alcohol dependence. Method: DNA from 92 alcohol-dependent patients and 92 healthy comparison subjects was genotyped for all three polymorphisms. Results: Variants at the - 75 base-pair ( bp) ( C allele) and - 159 bp ( A allele) positions were associated with alcohol dependence. Individuals with haplotypes carrying both risk alleles showed an odds ratio of 2.9. Conclusions: These preliminary results suggest that ADH4 may play a role in the etiology of alcohol dependence. The association requires further study and replication but is functionally plausible and has a large effect size.