Serotonin-Related Gene Variants in Patients with Irritable Bowel Syndrome and Depressive or Anxiety Disorders

Abstract

Aim. To assess the association of six polymorphisms in serotonin-related genes with depressive or anxiety disorders in patients with irritable bowel syndrome (IBS).Methods. The lifetime prevalence of depressive and anxiety disorders was assessed in 95 IBS patients (85% women) using the Munich version of the Composite International Diagnostic Interview (CIDI). IBS was diagnosed according to the Rome III criteria.SCL6A4HTTLPR polymorphism (rs4795541) was determined using PCR-based method. Single-nucleotide polymorphisms inHTR1A(rs6295),HTR2A(rs6313 and rs6311),HTR2C(rs6318), andTPH1(rs1800532) were detected by minisequencing method.Results. IBS patients with depressive disorders were characterized by higher frequency of 5-HTTLPR L allele in comparison to IBS patients with anxiety disorders. The lower frequency of 1438 A allele inHTR2Awas found in IBS patients with depressive disorders in comparison to IBS patients without mental disorders. The lower G allele frequency inHTR2Crs6318 polymorphism among IBS patients with anxiety disorders was also observed.Conclusions. Our results provide further evidence for the involvement ofSLC6A4rs4795541 andHTR2Ars6311 polymorphisms in the pathophysiology of depressive disorders in IBS patients. The new findings indicate thatHTR2Crs6318 polymorphism may be associated with the susceptibility to anxiety disorders in IBS patients.