title: Cannabinoid receptor 1 gene polymorphism and irritable bowel syndrome in the Korean population: a hypothesis-generating study.
abstract: OBJECTIVE
  The cannabinoids affect gastrointestinal function and are thought to be involved in the pathogenesis of irritable bowel syndrome (IBS). We hypothesized that genetic variants of the cannabinoid receptor 1 gene (CNR1) might be associated with IBS.
  
  
  METHODS
  One hundred sixty-two IBS patients, who met the Rome II criteria, and 423 healthy controls were subjected to genotyping of polymorphic triplet AAT repeats located in the 3-flanking region of the CNR1 gene.
  
  
  RESULTS
  Allele frequencies of AAT triplet repeats in the CNR1 gene differed markedly between the controls and IBS patients (P<0.01). Controls had a lower frequency of distribution of 10 alleles or more. We divided the alleles into 2 groups (≤ 10 and >10), and 3 genotypes ≤ 10/≤ 10, heterozygote, and >10/>10. The CNR1 having>10/>10 AAT triplet repeats occurred with greater frequency in IBS patients than in the controls (P<0.01). A strong genotype association was observed between the CNR1 >10/>10 genotype and all IBS subtypes compared with controls (P<0.01 for each). The allele frequencies and the CNR1 genotypes did not differ between the 3 IBS subtypes. Symptom scores for abdominal discomfort or pain were higher in patients with the CNR1 >10/>10 genotype than in patients with the other genotypes (P<0.05).
  
  
  CONCLUSIONS
  We found a different distribution of allelic frequency of AAT repeats in the CNR1 gene in healthy controls and IBS patients, and a significant association between the CNR1 >10/>10 genotype and IBS. These results suggest that the CNR1 gene is a potential candidate gene involved in IBS in Korea.
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Jae Myung
authors.initials: JM
authors.lastname: Park
authors.forename: Myung-Gyu
authors.initials: MG
authors.lastname: Choi
authors.forename: Yu Kyung
authors.initials: YK
authors.lastname: Cho
authors.forename: In Seok
authors.initials: IS
authors.lastname: Lee
authors.forename: Sang Woo
authors.initials: SW
authors.lastname: Kim
authors.forename: Kyu Yong
authors.initials: KY
authors.lastname: Choi
authors.forename: In-Sik
authors.initials: IS
authors.lastname: Chung
mesh_terms: D015746:Abdominal Pain / Q000209:etiology / Q000235:genetics*; D000328:Adult; D000483:Alleles; D044466:Asian People; D016022:Case-Control Studies; D005260:Female; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000235:genetics* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D043884:Receptor, Cannabinoid, CB1 / Q000235:genetics*; D056910:Republic of Korea
chemical_list: D043884:Receptor, Cannabinoid, CB1