Polymorphisms in the Uncoupling Protein 2 Gene Are Associated with Diabetic Retinopathy in Han Chinese Patients with Type 2 Diabetes.

Background: The uncoupling protein 2 (UCP2) gene plays an important role in the complications of type 2 diabetes (T2D). However, the association between variants in the UCP2 gene and diabetic retinopathy (DR) in Han Chinese T2D patients remains unclear. Methods: Two single-nucleotide polymorphisms (SNPs) [rs659366 (-866G/A) and a 45-bp insertion/deletion (I/D) in the 3'-UTR] in the UCP2 gene were genotyped in a study cohort of 209 T2D patients with DR and 199 T2D patients without DR by direct DNA sequencing. Results: Logistic regression analysis showed that the AA and GA genotypes of rs659366 were significantly associated with an increased risk for nonproliferative DR (NPDR) in the codominant model (corrected p-value <0.01) and the dominant model (corrected p-value=0.006). Patients harboring the II and DI genotypes had a higher risk for PDR in the codominant model (corrected p-value=0.011) and the dominant model (corrected p-value=0.006), and the DI genotype showed a higher risk for NPDR in the dominant model (corrected p-value=0.007) or codominant model (corrected p-value=0.006). Further, haplotype analyses verified that the A-I haplotype is a risk haplotype for NPDR and PDR. Conclusion: This study suggests that the UCP2 gene may be involved in the pathogenesis of NPDR and PDR in Han Chinese patients with T2D.