Interaction Between the VNTR of the DAT1 gene and DAT1 Methylation in Relation to Impulsivity in Combat Sports Athletes

Background: Dopaminergic signaling is a key mechanism in behavioral regulation and impulse control. While DAT1 promoter methylation has been linked to behavioral dysregulation in clinical groups, its role in high-functioning populations such as elite athletes remains unclear. Objectives: To compare DAT1 promoter methylation, DAT1 VNTR genotype, and impulsivity between elite combat sport athletes and matched controls, and to assess potential gene–environment interactions. Methods: The study included 209 male participants (100 elite combat athletes, 109 controls). Methylation of 33 CpG sites within the DAT1 promoter was quantified from peripheral blood DNA. DAT1 VNTR genotypes were determined via PCR and gel electrophoresis. Impulsivity was assessed using the Barratt Impulsiveness Scale (BIS-11). Group differences and interactions were analyzed using analysis of variance (ANOVA), non-parametric tests, and post hoc comparisons. Results: Athletes displayed significantly higher overall DAT1 promoter methylation and lower impulsivity scores across all BIS-11 subscales compared with controls. A significant group × genotype interaction for methylation indicated genotype-specific epigenetic differences by athletic status. No differences in VNTR genotype or allele frequencies were observed. Conclusions: Elevated DAT1 promoter methylation in elite athletes may be associated with enhanced behavioral control, potentially reflecting neurobiological adaptations to high-intensity training. These results highlight the need to integrate genetic and epigenetic perspectives in sports science. Longitudinal and multi-omics studies are warranted to determine causal links and evaluate the potential of epigenetic markers as indicators of performance-related traits.