COMT and Borderline personality disorder: Using targeted approaches aimed at well-known psychiatric candidate genes, epigenetic dysregulation in the blood of BPD patients has been reported e.g., for the serotonin receptor 2A (HTR2A), the monoamine oxidase A and B (MAOA and MAOB), the soluble catechol-o-methyltransferase (S-COMT), the glucocorticoid receptor (GR/NR3C1) (all reported by [16]), and the brain-derived neurotrophic factor (BDNF) [17].