Polymorphisms of DNA repair genes OGG1 and XPD and the risk of age-related cataract in Egyptians

PURPOSE: To analyze the association of the polymorphisms of xeroderma pigmentosum complementation group D (XPD) and 8-oxoguanine glycosylase-1 (OGG1) genes with the risk of age-related cataract (ARC) in an Egyptian population. METHODS: This case-control study included 150 patients with ARC and 50 controls. Genotyping of XPD Asp(312)Asn was performed by amplification refractory mutation system PCR assay and genotyping of OGG1 Ser(326)Cys was carried out by PCR including confronting two-pair primers. RESULTS: The Asn/Asn genotype of XPD gene was significantly associated with increased risk of ARC (odds ratio [OR] = 2.74, 95% confidence interval [CI] = 1.01–7.43, p = 0.04) and cortical cataract (OR = 5.06, 95% CI = 1.70–15.05, p = 0.002). The Asn(312) allele was significantly associated with an increased risk of ARC (OR = 1.75, 95% CI 1.06–2.89, p = 0.03) and cortical cataract (OR = 2.81, 95% CI = 1.56–5.08, p<0.001). The OGG1 Cys/Cys genotype frequency was significantly higher in ARC (OR = 4.13, 95% CI = 0.93–18.21, p = 0.04) and the Cys(326) allele (OR = 1.85, 95% CI = 1.07–3.20, p = 0.03). Moreover, the Cys/Cys genotype of the OGG1 gene was significantly higher in cortical cataract (OR = 6.00, 95% CI = 1.24–28.99, p = 0.01) and the Cys(326) allele was also significantly associated with cortical cataract (OR = 2.45, 95% CI = 1.30–4.63, p = 0.005). CONCLUSIONS: The results suggest that the Asn/Asn genotype and Asn(312) allele of XPD polymorphism, as well as the Cys/Cys genotype and Cys(326) allele of the OGG1 polymorphism, may be associated with increased risk of the development of ARC, particularly the cortical type, in the Egyptian population.