Background/Aims: Serotonin is an important mediator of intestinal peristalsis and it undergoes reuptake by a transporter protein (SERT). It has been reported that polymorphisms in the promoter for synthesis of SERT (SERT-P) influence the response to a serotonin reuptake inhibitor and a serotonin receptor antagonist. The aim of this study was to investigate gene polymorphism in the SERT-P in healthy adults and patients with irritable bowel syndrome (IBS) and a plasma serotonin level according to genetic polymorphism. Methods: SERT gene polymorphism was assessed by polymerase chain reaction on DNA chains in serum samples from 53 patients with IBS and 56 healthy adults. The platelet-depleted plasma serotonin level of a fasting state was quantitatively measured by ELISA. Results: There was no significant difference in the allele frequency between the IBS and the control group, and according to the subtypes of IBS patients. The platelet-depleted plasma serotonin level was significantly higher in IBS patients than in controls (P<0.05). However, there was no significant difference in the plasma serotonin level according to the subtypes of IBS or genetic polymorphism of SERT-P. Conclusions: SERT-P is not a key factor in determining the development of IBS in Korea. Patients with IBS have significantly higher fasting plasma serotonin levels than controls, irrespective of genetic polymorphism at SERT-P.ope
