5-Hydroxy tryptamine transporter (5HTT) gene promoter region polymorphism in anxiety and depressive disorders

  Background :5HTTLPR polymorphism (5- Hydroxytryptamine transporter linked promoter region polymorphism) is the most widely studied genetic variant in psychiatry. The present study is a modest effort at ascertaining the role of 5HT transporter linked promoter region polymorphism (5HTTLPR) in anxiety and depressive disorders in Kashmir (India).The aim of this study was to examine 5-Hydroxy tryptamine transporter (5HTT) gene promoter region polymorphism in anxiety and depressive disorders.   Methods :Thirty patients with unipolar depressive disorders, 30 patients with anxiety disorders and 40 healthy volunteers (controls) were studied on a case control design, using polymerase chain reaction (PCR) and agarose gel electrophoresis after digestion with endonuclease enzyme. Genotypes and allele frequencies were compared using chi square tests, and p value of < 0.05 was considered as statistically significant.   Results : The mean (±sd) HAM-A (Hamilton rating scale for anxiety) scores for anxiety and depressive groups were 28.2±5.14 and 17±5.61, respectively (P < 0.001). The mean (±sd)HAM-D (Hamilton rating scale for depression) scores for depressive and anxiety groups were 25±5.58 and 15±6.13, respectively. (p< 0.001). The frequency of S allele was significantly high (83.3% vs 60%) in the group with anxiety (p< 0.05) compared to the control group (p> 0.05).   Conclusion : The genetic studies are still evolving as pathogenesis of anxiety and depressive disorders and involve the interaction of environmental factors with various genes. Genetic variation in different populations and hence different environments is important for elucidation of the mechanisms of these disorders. However, the study concludes that the locus under study is not shared between the two disorders.