Purpose: Endothelin-1, and constitutive endothelial nitric oxide synthase, have been implicated in the pathogenesis of diabetic retinopathy. We therefore screened polymorphisms within the genes encoding these two vasoactive agents in a sample of individuals with 15 years of diabetes and no retinopathy (ETDRS level 10 or better) and those with severe retinopathy (ETDRS level 50 or worse).
Methods: PCR primers for highly polymorphic sites within the EDN1 and NOS3 genes were used to genotype individuals with type 1 or type 2 diabetes with severe or no retinopathy. Allele frequencies were compared between groups using chi-squared analysis and adjusting for multiple comparisons.
Results: No significant differences were observed in allele frequencies for these two markers between the patients who had retinopathy and the patients who did not.
Conclusion: Polymorphic variability in the EDN1 and NOS3 genes does not appear to have a major impact on determining susceptibility or resistance to diabetic retinopathy.