Association between a functional polymorphism in the monoamine oxidase A gene promoter and major depressive disorder

Various polymorphisms of the X-chromosomal monoamine oxidase A (MAO-A) gene were investigated for association with affective disorders. However, none of the studied variants could consistently be associated with either major depressive or bipolar affective disorder. Recently, a positive association between panic disorder and a novel functional repeat polymorphism in the MA O-A gene promoter, with the longer alleles being more active, was reported. Since monoaminergic neurotransmission is supposed to play an important rol e in affective disorders, we investigated a potential association of this p olymorphism with major depressive illness in a sample of 146 unrelated pati ents of German descent and a control group of 101 individuals with a negati ve life history for affective disorders, Similarly to the recent findings i n panic disorder, we observed a significantly increased frequency of genoty pes containing only long alleles in female patients with recurrent major de pression in comparison with age- and sex-matched controls, Thus, our data s uggest that an excess of high-activity MAO-A gene promoter alleles resultin g in an elevated MAO-A activity is a risk factor for major depressive disor der in females. (C) 2000 Wiley-Liss, Inc.