Genetic polymorphisms in DNA repair genes OGG1, APE1, XRCC1, and XPD and the risk of age-related cataract.

PURPOSE: To analyze the association of the polymorphisms in 8-oxoguanine glycosylase-1 (OGG1), X-ray repair cross-complementing-1 (XRCC1), and AP endonuclease-1 (APE1) genes in the base excision repair pathway and xeroderma pigmentosum complementation group D (XPD) in the nucleotide excision repair pathway with the risk of cataract in a Chinese population. DESIGN: Case-control study. PARTICIPANTS: Subjects with cataract (n = 415) or no cataract (n = 386) in the Age Related Eye Disease Ancillary Study. METHODS: The study included 415 cataract patients and 386 controls. Genotyping was carried out by the polymerase chain reaction-restriction fragment length polymorphism method. Differences in the frequencies were estimated by the chi-square test, and risk was estimated by using unconditional logistic regression after adjusting for age and gender. MAIN OUTCOME MEASURES: Association of single nucleotide polymorphisms in OGG1-Ser326Cys with the development of age-related cataract. RESULTS: The OGG1 Cys/Cys genotype frequency was significantly higher in cataract patients (P = 0.014; odds ratio [OR], 2.06; 95% confidence interval [CI], 1.171-3.624). The OGG1 Ser/Ser genotype (P = 0.003; OR, 0.647; 95% CI, 0.487-0.860) seems to have a protective role against cataract, and the Cys allele (P<0.001; OR, 1.517; 95% CI, 1.204-1.911) seems to have a deleterious role in the development of cataract. The genotype frequency of the Ser/Ser of OGG1-Ser326Cys was significantly different in the cortical and mixed-type cataract group (P = 0.014; OR, 0.591; 95% CI, 0.391-0.893; and P = 0.035; OR, 0.639; 95% CI, 0.425-0.960; respectively), and the Cys/Cys genotype of OGG1-Ser326Cys was significantly different in the mixed-type cataract group (P = 0.012; OR, 2.610; 95% CI, 1.284-5.306) compared with that of healthy controls. In XRCC1-Arg399Gln, APE1-Asp148Glu, and XPD-Lys751Gln polymorphisms, there were no significant differences in frequencies of the variant homozygous in patients compared with controls. CONCLUSIONS: Results suggest that the Cys/Cys genotype of the OGG1-Ser326Cys polymorphism may be associated with increased risk of age-related cataract. However, in XRCC1-Arg399Gln, APE1-Asp148Glu, and XPD-Lys751Gln polymorphisms, there were no significant differences in frequencies of the variant homozygous in patients compared with controls.

Association of a rare haplotype in Kinesin light chain 1 gene with age-related cataract in a han chinese population.

PURPOSE: The causal genes for congenital cataract are good candidates for the genetic susceptibility for age-related cataract (ARC). The aim of this study was to investigate association between the polymorphisms in the causal genes for congenital cataract and ARC in a Chinese population. Meanwhile, we performed the replication study for previous identified risk genes for ARC. METHODS: We recruited 212 sporadic Han Chinese patients with age-related cataracts (ARC) and 172 normal controls in this study. We analyzed 31 SNPs from 13 genes which mostly possible contributes the progress of ARC in a Chinese population, comprising 212 cataract patients and 172 controls. Polymorphism-spanning fragments were amplified by using the multiplex polymerase chain reaction (PCR) and genotyped using primer extension method in MassARRAY platform. Allelic and haplotypic difference in the frequencies were estimated using the SHEsis software platform. P-value was adjusted by the Bonferroni correction. RESULTS: There was no difference in the frequencies of the genotype and allele of the all SNPs between the patients with ARC and the controls. In the haplotypic analysis, the haplotypes consisting of rs7154572, rs7150141 and rs12432994 in Kinesin Light Chain 1 Gene (KLC1) showed significant association with ARC (p = 0.000878). A rare haplotype CGT was more frequent in patients (p = 0.000106, and p = 0.00795 after corrected for 75 tests). CONCLUSIONS: Our study provides evidence that the combined effect of three variants within the KLC1 gene may predispose to ARC, but the precise mechanism needs further investigating.