MAOA and Borderline personality disorder: Previous methylation studies in BPD have investigated individual regions coding for BDNF [38, 39], NR3C1 [40–44], FKBP5 [40, 41], DRD2 [45], HTR3A, HTR2A [44, 46], MAOA and MAOB [44], COMT [44], and OXTR [40].