Association Of Serotonin Transporter Gene Polymorphisms With Functional Dyspepsia And Accompanying Psychiatric Symptoms

Background and objectiveFunctional dyspepsia is a symptomatically defined clinical disorder, the diagnosis of which is based on chronic or recurrent symptoms thought to be from upper gastrointestinal tract, with the absence of organic diseases likely to explain the symptoms. The main symptoms of FD are postprandial fullness, early satiation, and pain or burning localized to the epigastrium. It is associated with significant morbidity leading to compromised quality of life, and huge economic loss because of direct expenses from medical care and indirect costs from sick leaves and sickness pensions. As a heterogeneous symptom complex, functional dyspepsia may comprise different subsets of patients with diverse pathophysiological mechanisms. To address the issue of heterogeneity, the Romeâ…¢(2006) criteria defined epigastric pain syndrome (EPS) and postprandial pain syndrome (PDS) as specific subgroups of functional dyspepsia. EPS is associated with postprandial fullness, early satiation, and PDS is associated with pain or burning localized to the epigastrium. The pathogenesy of FD is involved in gastric emptying, visceral hypersensitivity and infection factors. Serotonin (5-hydroxytryptamine or 5-HT) is an important factor in gut function, playing a critical role in intestinal peristalsis and secretion, and in sensory signaling in the brain-gut axis. Enterochromaffin cells, located primarily at the base of the epithelial crypts in the gastrointestinal tract, contain more than 95% of the total 5-HT within the human body. Recent research suggested the hypotheses that the functional gastrointestinal disorders(FGIDs)may be partly related to genetic factors.The aim of the present study was to assess the potential association between SERT polymorphisms and the FD subtype by classifying the patients according to Romeâ…¢diagnostic code of FD. Patients with FGIDs, such as chronic constipation, irritable bowel syndrome, and functional dyspepsia are often accompanied by emotional state changes. Some studies have shown that the polymorphism in the SERT gene may be associated with the development of IBS patients with psychiatric symptoms of depression.In the research the potential association between SERT polymorphisms and the FD-associated psychiatric symptoms was assessed to provide more evidence for the clinical treatment of FD.Methods1. Polymerase chain reaction (PCR) was used to detect the SERT gene-linked polymorphic region and the variable number tandem repeats in intron 2 of the SERT gene in 60 patients with FD and 80 healthy subjects.2. Data was entered and analyzed by SPSS version 16.0.Results1. No significant differences were noted in genotype distribution frequency of 5-HTTLPR between controls and FD patients. And there weren't significant differences in 5-HTTLPR genotype distribution frequencies among groups classified according to FD subtype and those according to psychiatric symptoms.2. There were significant differences in 5-HTTLPR S allele frequencies among groups classified according to FD subtype and those according to psychiatric symptoms. (all P<0.05).3. No significant differences were noted in genotype distribution or allele frequency of VNTRs between controls and FD patients.Conclusion1. The S allele of 5-HTTLPR may be associated with the development of FD-PDS subtype and FD-associated psychiatric symptoms.2. The occurrence of FD clinical symptoms and psychiatric symptoms associated with it may have the same genetic mechanism.There is high prevalence of common mental disorders among patients with functional dyspepsia and maybe this needs to be addressed while treating patients.