DBH −1021C>T and COMT Val108/158Met genotype are not associated with the P300 ERP in an auditory oddball task

ObjectiveThe amplitude and latency of the P300 may be associated by variations in dopaminergic genes. The current study was conducted to determine whether functional variants of the catechol-O-methyltransferase (COMT) and dopamine beta-hydroxylase (DBH) gene were associated with P300 amplitude and latency in an auditory oddball task.MethodsThe P300 ERP was assessed by a two-tone auditory oddball paradigm in a large sample of 320 healthy volunteers. The Val108/158Met polymorphism (rs4680) of the COMT gene and the −1021C>T polymorphism (rs1611115) of the DBH gene were genotyped. P300 amplitude and latency were compared across genotype groups using analysis of variance.ResultsThere were no differences in demographic characteristics in subjects for genotypic subgroups. No genotype associations were observed for the P300 amplitude and latency on frontal, central and parietal electrode positions.ConclusionsCOMT Val108/158Met and DBH −1021C>T polymorphisms do not show evidence of association with characteristics of the P300 ERP in an auditory oddball paradigm in healthy volunteers.SignificanceWe failed to find evidence for the association between dopaminergic enzymatic polymorphisms and the P300 ERP in healthy volunteers, in the largest study undertaken to date.

► The results revealed that neither COMT Val108/158Met in isolation nor the interaction with the DBH −1021C>T polymorphism accounted for variation in the P300 ERP.
► The present study for the first time demonstrated that the DBH −1021C>T polymorphism does not significantly mediate the P300 ERP.
► Earlier contradictory results regarding the potential modulation of the P300 ERP by the COMT Val108/158Met gene variant were resolved by showing that no such association exists in a large healthy population sample.