DRD2 C32806T modifies the effect of child-rearing environment on adulthood novelty seeking

Preliminary evidence suggests that there may be longitudinal interactions between environmental and genetic factors in predicting Novelty seeking. We have previously found in small and selected subsample from the Cardiovascular Risk in Young Finns study, that an association between the polymorphism of dopamine receptor D4 was moderated by the childhood environment, as indexed by hostile maternal child-rearing. We wanted to replicate this finding in a population based sample of 1,114 men and women using another candidate gene of dopaminergic system, that is, the dopamine receptor D2 (DRD2). The child-rearing environment of the participants was assessed by their mothers when the participants were children or adolescents, and adulthood Novelty seeking was self-rated by the participants 17 and 21 years later at the ages of 24-39. Genotyping of DRD2 C32806T (rs 1800497) was performed using TaqMan 5'nuclease assay. DRD2 was not directly associated with Novelty seeking, but there was a significant DRD2 x strict maternal disciplinary style interaction in predicting Novelty seeking (F = 7.08, P = 0.008). The interaction showed that when the child-rearing environment was punitive, participants carrying any A1 allele of the DRD2 gene had higher scores on Novelty seeking than carriers of the A2/A2 genotype. The genotype had no effect on Novelty seeking when the childhood environment was more favorable. The findings suggest that the DRD2 may have an environmentally moderated impact on Novelty seeking and that the origins of such an association may lie already in childhood.