title: Association between exudative age-related macular degeneration and the G6721T polymorphism of XRCC7 in outdoor subjects.
abstract: OBJECTIVE
  To investigate whether the G6721T polymorphism (rs.7003908) of the non-homologous end-joining DNA repair XRCC7 gene contributes to the development of exudative age-related macular degeneration (ARMD).
  
  
  METHODS
  The present case-control study consisted of 111 patients with exudative ARMD and 112 sex frequency-matched healthy controls that were randomly selected from unrelated volunteers in the same clinic. Genotypes were determined by the Restriction Fragment Length Polymorphism (PCR-RFLP) based method. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for ARMD risk associated with polymorphism of XRCC7. In all analysis the GG genotype was considered to be the reference genotype.
  
  
  RESULTS
  There was no significant association between genotypes of XRCC7 and susceptibility to ARMD. Considering the significant difference in age distribution between cases and controls, age was used as a covariate in further analysis. After ORs were adjusted for age, the same result was observed. In the next step we stratified our subjects into outdoor and indoor groups according to their job titles. The outdoor and indoor patients were occupationally exposed to sunlight and not exposed to sunlight, respectively. Our present study showed that among indoor subjects there was no association between XRCC7 polymorphism and susceptibility to ARMD. However, among outdoor subjects, the GT + TT genotypes compared to the GG genotype increased the risk of ARMD (OR, 3.13; 95% CI, 1.04-9.39; p = 0.042).
  
  
  CONCLUSIONS
  Our study revealed that the T allele of the G6721T polymorphism of XRCC7 increased the risk of ARMD among outdoor subjects.
authors.affiliation: Department of Biology, Shiraz University College of Sciences, Shiraz, Iran.
authors.forename: Iraj
authors.initials: I
authors.lastname: Saadat
authors.forename: Roghayyeh
authors.initials: R
authors.lastname: Vakili-Ghartavol
authors.forename: Majid
authors.initials: M
authors.lastname: Farvardin-Jahromi
authors.forename: Mostafa
authors.initials: M
authors.lastname: Saadat
mesh_terms: D000368:Aged; D004247:DNA / Q000235:genetics*; D051747:DNA-Activated Protein Kinase / Q000235:genetics* / Q000378:metabolism; D004781:Environmental Exposure; D005122:Exudates and Transudates; D005260:Female; D005500:Follow-Up Studies; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008268:Macular Degeneration / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D009687:Nuclear Proteins; D004247:DNA; D051747:DNA-Activated Protein Kinase; C497263:PRKDC protein, human