Supplementary Material for: Genetic Variants in ICAM1, PPARGC1A and MTHFR Are Potentially Associated with Different Phenotypes of Diabetic Retinopathy

Purpose: To explore phenotype-genotype correlations that may contribute to a better understanding of diabetic retinopathy (DR). Procedures: An exploratory association study was performed to identify genetic variants associated with non-proliferative DR (NPDR) in 307 type 2 diabetic patients who were previously stratified into 3 different phenotypes of NPDR progression. The 307 patients were genotyped for 174 single nucleotide polymorphisms of 11 candidate genes (ACE, AGER, AKR1B1, ICAM1, MTHFR, NOS1, NOS3, PPARGC1A, TGFB1, TNF and VEGFA). Results: Significant associations were observed for PPARGC1A rs16874120 with phenotype A (odds ratio, OR = 0.60, 95% confidence interval, CI 0.36-0.99), ICAM1 rs1801714 with phenotype B (OR = 3.32, 95% CI 1.05-10.50) and both PPARGC1A rs10213440 (OR = 2.00, 95% CI 1.07-3.73) and MTHFR rs1801133 (OR = 1.84, 95% CI 1.08-3.11) with phenotype C. Conclusions: Results indicate that specific gene variants in ICAM1, PPARGC1A and MTHFR are associated with different NPDR phenotypes, being likely candidates to explain different disease mechanisms underlying the different phenotypes. This is the first study to show correlations between specific gene variants and NPDR phenotypes, opening new perspectives on DR.