GENETIC ASSOCIATION BETWEEN REDUCED P300 AMPLITUDE AND THE DRD2 DOPAMINE-RECEPTOR A1 ALLELE IN CHILDREN AT HIGH-RISK FOR ALCOHOLISM

Background: There is evidence that both reduction in P300 amplitude an d the presence of the Al allele are risk markers for alcoholism We hyp othesized that demonstration of a relationship between the marker and the trait in young children who had nor begun to drink regularly would provide evidence for dopaminergic mediation of the reduction in P300 often seen among high-risk children. A previous association between th e Al and the P300 amplitude in screened controls supports the hypothes is that this association occurs in the general population. Methods: Ch ildren were assessed using both visual and auditory paradigms to elici t event-related potentials (ERPs). The P300 component of the ERP was i nvestigated with respect to the genetic variation of the Taq1A D2 rece ptor in these children. Results: Generic association between a marker locus (Taq1 A RFLP near the D2 receptor locus) and the amplitude of P3 00 was found to be present in 58 high-risk children and their relative s (a total of 100 high-risk individuals). Conclusions: A higher propor tion of children from alcoholic families may exhibit lower P300 becaus e more of these children carry the Al allele than is seen in the norma l population. (C) 1998 Society of Biological Psychiatry.