Polymorphic monoamine oxidase a and 5-HT-transporter genes: Analysis of interactions with panic disorder

An excess of higher active, long MAO-A promoter alleles was described in women with panic disorder (Deckert et al., Human Molecular Genetics 8:621-624, 1999). For the less-active, short allele of a 5-HT-transporter promoter polymorphism an association with anxiety-related personality traits has been reported (Lesch et al., Science 274:1527-1531, 1996). We performed an analysis of possible synergistic effects in a German and an Italian sample (combined n=144, panic disorder and n=175, control). The described excess of higher active, long MAO-A promoter alleles among women with panic disorder was also found in this subsample of the original sample (p=0.02, Chi Square analysis). This effect was not modified by the different 5-HT-transporter promoter alleles. Only in men, a non-significant increase of the odds ratio by a factor of 2 in the presence of both the long MAO-A and 5-HT-transporter promoter alleles was observed (p=0.45). The statistical power even of the combined samples, however, was too small to detect an effect of this size with a significance level of p=0.05. As the contribution of individual genes to the pathogenesis of panic disorder is small, larger samples and wider collaborations will be necessary.