Association studies of MAO-A, COMT, and 5-HTT genes polymorphisms in patients with anxiety disorders of the phobic spectrum.

Recent studies provide evidence that anxiety disorders may be linked to malfunction of serotonin neurotransmission or impaired activity of enzymes metabolising the catecholamines. Functional polymorphisms in the MAO-A uVNTR promoter gene, the COMT gene (Val158Met) exon 4, and the 5-HTT promoter gene (44 bp ins/del) were investigated in 101 patients with phobic disorders of the anxiety spectrum and 202 controls matched to the patients for sex, age and ethnicity. There were no significant differences between controls and patients in the allele and genotype frequencies of the 5-HTT and COMT gene polymorphisms. The frequency of >3 repeat alleles of the MAO-A gene polymorphism was significantly higher in female patients suffering from anxiety disorders, specifically panic attacks and generalized anxiety disorder. There was also a trend for the more frequent presence of >3 repeat alleles in female patients with agoraphobia and specific phobia, in contrast to female patients with social phobia, who did not differ from controls. The results support a possible role of the MAO-A gene in anxiety disorders.