Background: Diabetic retinopathy is the most severe diabetic microvascular complication that causes changes in the vessel wall. One of the genes involved in this disease is PON1, which encodes paraoxanase1 protein in liver and kidney. It might regulate inflammatory and microvascular responses to the disease. The rs662 T>C is one of the single nucleotide polymorphisms of this gene that changes glutamine to arginine at position 192. Methods: In this study, 300 samples were collected, including 100 healthy and 100 diabetics without retinopathy, and 100 diabetics retinopathies were studied and their age range was from 30 to 80 years. Then 2.5 ml of blood was collected from all relevant individuals in tubes containing EDTANa2. This polymorphism was examined by tetra-ARMS PCR. Results: Results showed that there is no significant correlation between genotypes and alleles related to PON1 and Diabetes (CC genotype: p=0.609; C allele: p=0.228). On the other hand, an association was observed between PON1 and diabetic retinopathy (CT+CC genotype: p<0.001; CT allele: p<0.001). Considering that the Polyphen database examined the changes caused by replacing the amino acid arginine instead of glutamine at position 129 on the protein, it does not consider these changes dangerous and has introduced this polymorphism as benign. Conclusion: Based on the findings of this study, the rs662 locus could be considered as one of the molecular markers in future research.
