title: Polymorphisms of DNA repair genes XPD (Lys751Gln) and XRCC1 (Arg399Gln), and the risk of age-related cataract: a meta-analysis.
abstract: OBJECTIVE
  A meta-analysis of available studies was used to test the association between two DNA repair genes and age-related cataract.
  
  
  METHODS
  A systematic search of the Chinese National Knowledge Infrastructure, EMBASE and PubMed databases identified six studies that were analyzed. Meta-analysis was used to evaluate single nucleotide polymorphisms (SNP) of the DNA repair gene xeroderma pigmentosum complementation group D (XPD) (Lys751Gln) and the X-ray repair cross-complementing gene 1 (XRCC1) (Arg399Gln). Only articles published before June 6, 2014, were included. The quality of the studies was determined using Newcastle-Ottawa Scale tools. The summary odds ratio (OR) and corresponding confidence interval (CI) for XPD Lys751Gln and XRCC1 Arg399Gln polymorphisms and risk of age-related cataract were estimated by random and fixed-effects models. Sensitivity analysis was employed to determine the robustness of the conclusions.
  
  
  RESULTS
  Six studies, with a total of 1518 patients with cataractous lenses and 1437 subjects with clear lenses, were included in the meta-analysis. XRCC1 Arg399Gln polymorphisms were associated with cataract risk (recessive model: ORfixed = 0.79, 95% CI: 0.67-0.93; dominant model: ORfixed = 0.84, 95% CI: 0.64-1.11; additive model: ORfixed = 0.82, 95% CI: 0.72-0.92). Analysis of Chinese, but not non-Chinese subgroups, confirmed this association. The OR of XPD Lys751Gln polymorphisms for cataract was not significant. The associations remained significant after sensitivity analysis.
  
  
  CONCLUSIONS
  This meta-analysis indicates that XRCC1 Arg399Gln polymorphisms, but not XPD Lys751Gln polymorphisms, are associated with risk of age-related cataract.
authors.affiliation: Department of Ophthalmology, Chinese PLA (People's Liberation Army) General Hospital , Beijing , China , and.
authors.forename: Xiao-Cui
authors.initials: XC
authors.lastname: Liu
authors.forename: Xiao-Fei
authors.initials: XF
authors.lastname: Liu
authors.forename: Zhi-De
authors.initials: ZD
authors.lastname: Hu
authors.forename: Zhao-Hui
authors.initials: ZH
authors.lastname: Li
mesh_terms: D000375:Aging / Q000235:genetics*; D044466:Asian People / Q000235:genetics; D002386:Cataract / Q000235:genetics*; D004260:DNA Repair / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D012150:Polymorphism, Restriction Fragment Length; D020641:Polymorphism, Single Nucleotide; D012307:Risk Factors; D000076105:X-ray Repair Cross Complementing Protein 1; D051759:Xeroderma Pigmentosum Group D Protein / Q000235:genetics*
chemical_list: D004268:DNA-Binding Proteins; D000076105:X-ray Repair Cross Complementing Protein 1; C000619371:XRCC1 protein, human; D051759:Xeroderma Pigmentosum Group D Protein; C497292:ERCC2 protein, human
keywords: Age-related cataract; DNA repair genes; meta-analysis; polymorphisms; risk of cataract