Institute for Behavioral Genetics, University of Colorado at Boulder, Boulder, CO 80309-0447, USA. brett.haberstick@colorado.edu
OBJECTIVE: Dopaminergic dysfunction has been hypothesized to play an important role in the etiology of alcohol-use disorders. A restriction fragment length polymorphism (RFLP) in the 3' untranslated region (3'UTR) of the DRD2 gene affects gene expression and has been implicated as a risk factor for alcohol dependence. This polymorphism (TaqIA) has been reported as positively associated with alcohol-use disorders in case-control samples, but these results have not been replicated in family-based association studies. The mixed results of association between the DRD2 TaqIA polymorphism and alcohol-use disorders may be the result of differences in sample size, phenotype definition, heterogeneity of the samples, and genetic admixture. METHOD: We conducted tests of association in a sample of 838 adults participating in the National Youth Survey Family Study (NYSFS). We examined whether the DRD2 TaqIA polymorphism was associated with a symptom-count measure of alcohol abuse and dependence derived from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, and the Craving Withdrawal Model. RESULTS: Tests of association were nonsignificant across each classification system examined. Power calculations suggested that these results were despite the ability to detect an effect size of 1%. CONCLUSIONS: This study supports other family-based association tests that have reported no association between the DRD2 TaqIA polymorphism and alcohol abuse and dependence.