Association of polymorphisms rs4680 of the Catechol-O-Methyltransferase gene and rs6265 of the brain derived neurotrophic factor gene with the behavioral inhibition and behavioral activation systems

Background: The Behavioral Inhibition System (BIS) comprises limbic circuitry implicated in avoidance behav-iors. Its increased activation has been identified as a risk factor for anxiety and depressive disorders. In addition, both Catechol-O-Methyltransferase (COMT) and Brain Derived Neurotrophic Factor (BDNF) have been postulated as candidate genes that constitute a vulnerability for the onset of anxiety and depressive disorders. The aim of this study was to evaluate the possible association between the rs4680 polymorphism of the COMT gene and the rs6265 polymorphism of the BDNF gene with the BIS and the Behavioral Activation System (BAS) in a population sample from Colombia. Methods: Genetic information was obtained by extracting DNA from blood samples of 80 participants and using Taqman probes designed for each polymorphism. In addition, participants completed a BIS/BAS scale in order to establish a neuropsychological classification.Results: The frequency of the Met allele of the BDNF gene was greater in the group with BIS sensitivity compared to the group with BAS sensitivity. On the contrary, the frequency of the Met allele of the COMT gen did not show a significant association with the BIS. Conclusions: The rs6265 polymorphism of BDNF gene is associated with the BIS which in turn constitutes a risk factor for anxiety and depression.