Epistatic interaction between COMT and DAT1 genes on eating behavior: a pilot study

Problems related to food and weight in women may be influenced by the (DA) dopamine system. Catechol-o-methyl transferase (COMT) and the dopamine transporter (DAT) exert control on concentrations of extracellular DA. High and low functioning alleles of the COMT Val158Met and DAT1 3' UTR VNTR polymorphisms have been identified, and their associations with reward and cognition suggest a role in the modulation of eating behavior. A sample of undergraduate college women (N=71) was characterized for binge eating and eating psychopathology and genotyped for the COMT and DAT1 markers. Results revealed a significant epistatic interaction between COMT and DAT1 genes on eating psychopathology and binge eating (p=.02 for both). This suggests that genetic studies of risk for maladaptive eating behavior involving the dopamine system should explicitly consider epistasis.