SLC6A4 and Borderline personality disorder: We studied 76 patients diagnosed with borderline personality disorder (BPD), characterized by extreme levels of personality traits, especially neuroticism (N), in which we genotyped two polymorphisms, the 5HTTLPR of the Serotonin transporter (SERT) gene, and the Val66Met of the Brain-derived neurotrophic factor (BDNF) gene.