title: Common PPARγ variants C161T and Pro12Ala are not associated with inflammatory bowel disease in an Australian cohort.
abstract: OBJECTIVE
  Peroxisome proliferator-activated receptor (PPAR) γ is a transcription factor, highly expressed in colonic epithelial cells, adipose tissue and macrophages, with an important role in the regulation of inflammatory pathways. The common PPARγ variants C161T and Pro12Ala have recently been associated with Ulcerative Colitis (UC) and an extensive UC phenotype respectively, in a Chinese population. PPARγ Pro12Ala variant homozygotes appear to be protected from the development of Crohn's disease (CD) in European Caucasians.
  
  
  METHODS
  A case-control study was performed for both variants (CD n=575, UC n=306, Controls n=360) using a polymerase chain reaction (PCR)-restriction fragment length polymorphism analysis in an Australian IBD cohort. A transmission disequilibrium test was also performed using CD trios for the PPARγ C161T variant. Genotype-phenotype analyses were also undertaken.
  
  
  RESULTS
  There was no significant difference in genotype distribution data or allele frequency between CD and UC patients and controls. There was no difference in allele transmission for the C161T variant. No significant relationship between the variants and disease location was observed.
  
  
  CONCLUSIONS
  We were unable to replicate in a Caucasian cohort the recent association between PPARγ C161T and UC or between PPARγ Pro12Ala and an extensive UC phenotype in a Chinese population. There are significant ethnic differences in genetic susceptibility to IBD and its phenotypic expression.
authors.affiliation: Inflammatory Bowel Diseases Laboratory, Queensland Institute of Medical Research, Herston, Australia. georgiaH@qimr.edu.au
authors.forename: Georgia E
authors.initials: GE
authors.lastname: Hume
authors.forename: Elizabeth V
authors.initials: EV
authors.lastname: Fowler
authors.forename: Lyn R
authors.initials: LR
authors.lastname: Griffiths
authors.forename: James D
authors.initials: JD
authors.lastname: Doecke
authors.forename: Graham L
authors.initials: GL
authors.lastname: Radford-Smith
mesh_terms: D016022:Case-Control Studies; D015331:Cohort Studies; D003093:Colitis, Ulcerative / Q000235:genetics; D003424:Crohn Disease / Q000235:genetics; D005787:Gene Frequency; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D005838:Genotype; D060148:HapMap Project; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000235:genetics*; D047495:PPAR gamma / Q000235:genetics*; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide
chemical_list: D047495:PPAR gamma