1. ¹Department of Neuroscience, New York State Psychiatric Institute, Department of Psychiatry, Columbia University College of Physicians & Surgeons, New York, NY, USA
2. ²Division of Child and Adolescent Psychiatry, Western Psychiatric Institute and Clinic, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA

Correspondence: Dr JJ Mann, Department of Neuroscience, New York State Psychiatric Institute, 1051 Riverside Drive, Unit 42, New York, NY 10032, USA. Tel: +1 212 543 5571; Fax: +1 212 543 6017; E-mail: jjm@columbia.edu

Received 19 November 2003; Revised 19 November 2003; Accepted 30 January 2004; Published online 19 May 2004.

Abstract

Monoamine oxidase A (MAOA) activity is altered in mood disorders and lower activity associated with aggressive behavior. The gene has a functional polymorphism with a variable number tandem repeat (VNTR) in the upstream regulatory region (MAOA-uVNTR). In this study, we examined possible associations between the MAOA-uVNTR polymorphism and mood disorders, suicidal behavior, aggression/impulsivity, and effects of reported childhood abuse. In total, 663 unrelated subjects with a psychiatric disorder and 104 healthy volunteers were genotyped for the 30 base pair functional VNTR. A novel repeat variation was identified. No statistically significant associations were found between this functional MAOA-uVNTR polymorphism and mood disorders or suicide attempts. However, the lower expression allele was associated with a history of abuse before 15 years of age in male subjects and with higher impulsivity in males but not females. Our results suggest that the lower expression of the MAOA-uVNTR polymorphism is related to a history of early abuse and may sensitize males, but not females, to the effects of early abuse experiences on impulsive traits in adulthood. The polymorphism may be a marker for impulsivity that in turn may contribute to the risk for abuse. This trait could then be further aggravated by abuse.