SIRT1 rs7895833 and SOD1-50bp ins/del Gene vVariations in Age-Related Cataract Patients: A Case-Control Study

Oxidative stress is one of the main factors has been implicated in pathophysiology of cataracts. Superoxide dismutase (SOD) can prepare the first line of defense versus detrimental reactive oxygen species (ROS) and Sirtuin (SIRT) confers protection against oxidative stress and retinal degeneration. Correlation of SOD1-50bp ins/del and SIRT1-rs7895833 polymorphisms with risk of cataracts is not studied currently. Therefore, we aimed to explore possible relationship between SOD1 (50bp ins/del) and SIRT1 (rs7895833) polymorphisms with the risk of cataracts in Iranian population.  Our study design consisted of 200 patients with age-related cataracts and 200 healthy individuals as a control group. After DNA extraction, the identification of polymorphisms was conducted using PCR-based methods and data analysis was done by SPSS software.  A significant difference in SOD1 DD genotype distribution was observed between studied groups (OR: 3.42, P:0.037), the D allele was more frequent in patients in comparison with controls (OR: 1.68, P:0.009). Also, in the dominant genetic model for the D allele (comparison between ID+DD vs. II), ID+DD genotypes increased the risk of cataracts (OR: 1.62, P: 034). The association between SIRT1-rs7895833 polymorphism and cataract was significant in the AG genotype (OR: 2.37, P<0.001) and G allele (OR: 1.97, P<0.001). The SIRT1-1 polymorphism increased the risk of cataracts in the dominant tested inheritance model (OR: 2.34, P<0.001). In the combined analysis of two polymorphisms, there is an additive effect of the high-risk putative alleles about the risk of cataracts. Risk estimation according to the number of high-risk alleles showed that χ2 for linear trend for 0, 1, 2, 3 and 4 putative high-risk alleles is equal to 20.10 (P<0.001).  The results showed that for the first time, SIRT1 rs7895833 and SOD1-50bp ins/del gene variations had additive effects on the risk of cataracts.