Tryptophan-hydroxylase 2 haplotype association with borderline personality disorder and aggression in a sample of patients with personality disorders and healthy controls

Background: There is a decreased serotonergic function in impulsive aggression and borderline personality disorder (BPD), and genetic association studies suggest a role of serotonergic genes in impulsive aggression and BPD. Only one study has analyzed the association between the tryptophan-hydroxylase 2 (TPH2) gene and BPD. A TPH2 " risk" haplotype has been described that is associated with anxiety, depression and suicidal behavior. Methods: We assessed the relationship between the previously identified " risk" haplotype at the TPH2 locus and BPD diagnosis, impulsive aggression, affective lability, and suicidal/parasuicidal behaviors, in a well-characterized clinical sample of 103 healthy controls (HCs) and 251 patients with personality disorders (109 with BPD). A logistic regression including measures of depression, affective lability and aggression scores in predicting " risk" haplotype was conducted. Results: The prevalence of the " risk" haplotype was significantly higher in patients with BPD compared to HCs. Those with the " risk" haplotype have higher aggression and affect lability scores and more suicidal/parasuicidal behaviors than those without it. In the logistic regression model, affect lability was the only significant predictor and it correctly classified 83.1% of the subjects as " risk" or " non-risk" haplotype carriers. Conclusions: We found an association between the previously described TPH2 " risk" haplotype and BPD diagnosis, affective lability, suicidal/parasuicidal behavior, and aggression scores.