Polymorphisms of the DNA repair genes XPD and XRCC1 and the risk of age-related cataract development in Han Chinese.

PURPOSE: Epidemiological evidence suggests that ultraviolet (UV) irradiation and oxidative stress play an important role in age-related cataract pathogenesis. UV irradiation and oxidative stress can produce a wide range of DNA damage. Polymorphisms of DNA repair enzymes may affect repair efficiency and the role of DNA repair mechanisms has received attention recently in age-related cataract pathogenesis. In this case-control study, The aim was to determine the frequency of polymorphisms in two DNA repair enzyme genes, xeroderma pigmentosum complementation group D (XPD) codon 751 and x-ray cross-complementing group 1 (XRCC1) codon 399, in patients with age-related cataract and in healthy controls.

METHODS: Polymerase chain reaction and restriction fragment length polymorphisms were used to analyze XPD T751G and XRCC1 G399A in 180 patients with age-related cataract and 174 healthy individuals as controls.

RESULTS: There was a significant difference between the case and control groups in the XRCC1399 genotype. The odds ratio of the XRCC1 G/A polymorphism compared with the G/G wild-type genotype was 1.92 (95% CI = 1.17-3.15, p = 0.01). Moreover, individuals who carried at least one A-allele (G/A or A/A) had a 1.68-fold increased risk of developing age-related cataract compared with those who carried the G/G wild type genotype (OR = 1.68; 95% CI: 1.05-2.68, p = 0.030). No statistically significant difference was found in the genotypic and allelic distributions of the polymorphisms in the XPD gene between the groups.

CONCLUSIONS: These results suggest that polymorphisms in XRCC1 codon 399 may be associated with the development of age-related cataract in Han Chinese.