Polymorphisms of the Serotonin Transporter Gene and G-Protein β3 Subunit Gene in Korean Children with Irritable Bowel Syndrome and Functional Dyspepsia

BACKGROUND/AIMS Many candidate gene studies have revealed that polymorphisms of the 5'-flanking controlled SERT gene linked polymorphic region (5HTT-LPR) gene and G-protein β3 C825T gene might be associated with functional dyspepsia (FD) and irritable bowel syndrome (IBS). This study was performed to investigate polymorphisms of the 5HTT-LPR gene and G-protein β3 C825T gene in FD and IBS in Korean children. METHODS In total, 102 patients with FD, 72 patients with IBS based on the Rome III criteria and 148 healthy controls without gastrointestinal symptoms were included in the study to analyze 5HTT-LPR and G-protein β3 C825T polymorphisms. RESULTS 5HTT-LPR genotype analysis revealed no signifi cant differences in FD and IBS patients compared with controls. The GNβ3 C825T genotype distribution for CC, CT, and TT was 23.6%, 53.4%, and 23.0% in controls, 36.3%, 38.2%, and 25.5% in FD and 37.5%, 38.9%, and 23.6% in IBS, respectively. The CC genotype was more common in FD and IBS patients than controls (p<0.05). When the IBS patients were grouped according to IBS subtypes, CC genotype GNβ3 C825T was common in diarrhea-dominant IBS, and the TT genotype was common in constipation-dominant IBS (p<0.05). CONCLUSIONS The CC genotype of G-protein β3 C825T may be associated with FD and diarrhea-predominant IBS. The TT genotype may be associated with constipation-predominant IBS.