title: A genetic association study of single nucleotide polymorphisms in GNβ3 and COMT in elderly patients with irritable bowel syndrome.
abstract: BACKGROUND
  Several polymorphisms have been reported to be associated with irritable bowel syndrome (IBS), including C825T, the single nucleotide polymorphism (SNP), responsible for a truncated G protein β3 subunit (GNβ3), and the Vall158Met substitution in catechol-O-methyltransferase (COMT). We investigated the association between these mutations and the prevalence of IBS in 66 elderly Chinese patients.
  
  
  METHODS
  Sixty-six patients (over age 60 years) were diagnosed with IBS according to the Rome III criteria, and divided into 3 groups based on symptom presentation. The groups consisted of 7 patients with constipation, 46 patients with diarrhea, and 13 patients with both or neither symptoms. We enrolled 115 age-matched individuals without IBS as the control group. All patients were evaluated by using the Geriatric Depression Scale, disease progression was recorded, and GNβ3 and COMT were genotyped by PCR.
  
  
  RESULTS
  There was no significant difference in GNβ3 C825T genotype distribution and allele frequency between the 2 groups. In contrast, compared with control subjects, COMT 158Met was significantly more prevalent in the IBS group (P=0.040) and significantly more prevalent in patients with diarrhea (P=0.029). 158Met was also more prevalent in those patients who had experienced symptoms for over 5 years (P=0.022).
  
  
  CONCLUSIONS
  In elderly Chinese patients, the 158Met SNP in COMT is associated with IBS pathogenesis, but the GNβ3-C825T SNP is not associated with IBS pathogenesis.
authors.affiliation: Department of Gerontology, Huashan Hospital, Affliated Fudan University, Shanghai, China (mainland).
authors.forename: Yuezhi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Gerontology, Huashan Hospital, Affliated Fudan University, Shanghai, China (mainland).
authors.forename: Zhengyu
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Department of Anesthesiology, Eye Ear Nose and Throat Hospital Affiliated to Fudan University, Shanghai, China (mainland).
authors.forename: Hui
authors.initials: H
authors.lastname: Qiao
authors.affiliation: Department of Gerontology, Huashan Hospital, Affliated Fudan University, Shanghai, China (mainland).
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000235:genetics*; D002394:Catechol O-Methyltransferase / Q000235:genetics*; D017931:DNA Primers / Q000235:genetics; D005787:Gene Frequency; D005838:Genotype; D020962:Heterotrimeric GTP-Binding Proteins / Q000235:genetics*; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000235:genetics* / Q000473:pathology; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*
chemical_list: D017931:DNA Primers; C454420:G-protein beta3 subunit; C588010:COMT protein, human; D002394:Catechol O-Methyltransferase; D020962:Heterotrimeric GTP-Binding Proteins