title: Functional parkin promoter polymorphism in Parkinson's disease: new data and meta-analysis.
abstract: BACKGROUND
  A functional SNP (rs9347683) in the promoter region of the parkin gene had been implicated as a risk factor in older Parkinson's disease (PD) patients.
  
  
  METHODS
  Using a case-control methodology, we genotyped the SNP in the promoter region of the parkin gene to investigate their association with risk of PD and conducted a pooled analysis of published papers in the English literature.
  
  
  RESULTS
  A total of 1087 study subjects comprising 595 patients with PD and 492 unrelated healthy controls were recruited. The frequency of "GG" genotype in the elderly sub-group (≥ 65 years) was higher in PD compared to controls (OR=1.11) though we did not observe any difference in allele or genotype frequencies between the cases and the controls (P>0.05) in the overall PD population. Those with genotype "GG" were associated with a higher Hoehn-Yahr stage compared with PD patients carrying "GT"+"TT" (P=0.040). A pooled analysis involving more than >3000 subjects revealed that the frequency of genotypes in PD patients did not differ from the controls (OR=0.98, 95% CI: 0.86-1.12). However, in the group ≥ 65 years of age, the "GG" genotype was higher in PD (OR=1.51, 95% CI: 1.06-2.13, P=0.020) among the ethnic Chinese.
  
  
  CONCLUSIONS
  While we did not demonstrate a significant association of the parkin promoter polymorphism with PD in our sample, the pooled data suggest that the variant may increase the risk of PD in the more elderly population among the ethnic Chinese, suggesting possible ethnicity-specific effect. Further in vitro and in vivo studies to evaluate this functional parkin variant are warranted.
authors.affiliation: Department of Neurology, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, China.
authors.forename: Xue-Li
authors.initials: XL
authors.lastname: Chang
authors.forename: Xue-Ye
authors.initials: XY
authors.lastname: Mao
authors.forename: Hui-Hua
authors.initials: HH
authors.lastname: Li
authors.forename: Jin-Hong
authors.initials: JH
authors.lastname: Zhang
authors.forename: Nan-Nan
authors.initials: NN
authors.lastname: Li
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Burgunder
authors.forename: Rong
authors.initials: R
authors.lastname: Peng
authors.forename: Eng-King
authors.initials: EK
authors.lastname: Tan
mesh_terms: D000368:Aged; D002681:China / Q000453:epidemiology; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D044767:Ubiquitin-Protein Ligases / Q000235:genetics*
chemical_list: D044767:Ubiquitin-Protein Ligases; C111567:parkin protein