Senile cataract and genetic polymorphisms of APE1, XRCC1 and OGG1

Polymorphisms of DNA repair enzymes which may influence their repair efficiency lead to diseases, for example, senile cataract. In this study, we aimed to analyze the association of single nucleotide polymorphisms in AP endonuclease-1 (APE1), 8-oxoguanine glycosylase-1 (OGG1) and X-ray repair cross-complementing-1 (XRCC1) genes with the risk of age-related cataract in a Chinese population. Genotyping was carried out by the polymerase chain reaction and DNA sequencing on 402 cataract patients and 813 controls in this study. Differences in the frequencies were estimated by the chi-square test, and risk was estimated using unconditional logistic regression after adjusting for age and gender. Our results demonstrated there was a significant difference between the case and control groups in the APE1-141 G/G genotype (P=0.002). This difference still existed after adjusting for age and gender (P-star=0.003). The APE1-141 T/T genotype and T allele frequencies were significantly higher in cataract patients, while the G/G genotype and G allele frequencies in patients were significantly lower than in controls (P < 0.05). The APE1-141 G/G genotype (OR, 0.49; 95% CI, 0.31-0.77) seems to have a protective role against cataract, and the T allele seems to have a deleterious role in the development of cataract. In OGG1 Ser326Cys and XRCC1 Arg399Gln polymorphisms, there were no significant differences in frequencies of the variant homozygous in patients compared with controls.