The TaqI A1 allele of the dopamine D2 receptor gene and alcoholism in Brazil: Association and interaction with stress and harm avoidance on severity prediction

Allele and genotype frequencies of the TaqI A polymorphism of dopamine D2 r eceptor (DRD2) gene were compared in 115 alcohol-dependent Brazilian males and 114 ethnically matched controls. Regression analyses were performed to test for an interactive effect Between the DRD2 TaqI Al allele and measures of stress and harm avoidance on severity of alcoholism and number of antis ocial personality symptoms. A slightly positive association of DRD2 TaqIA1 genotypes with alcoholism was observed, by standard and molecular heterosis approaches. The DRD2 TaqI Al allele showed significant interaction with st ress and harm avoidance in predicting the severity of physiologic dependenc e, and with harm avoidance for the number of antisocial personality symptom s. Separate partial correlation analyses showed that stress-related variabl es were significantly correlated with severity scores in alcoholics with th e allele, but not in those without it, This is the first demonstration of a n interaction between a genetic polymorphism and stress-related measures on the severity of psychiatric disorders. Am. J. Med, Genet. (Neuropsychiatr. Genet,) 96: 302-306, 2000, (C) 2000 Wiley-Liss, Inc.