Gene-gene interaction of erythropoietin gene polymorphisms and diabetic retinopathy in Chinese Han

The aim of this study was to investigate the association of three single nucleotide polymorphisms in the erythropoietin gene polymorphisms with diabetic retinopathy and additional role of gene-gene interaction on diabetic retinopathy risk. A total of 1193 patients (579 men, 614 women) with type 2 diabetes mellitus were selected, including 397 diabetic retinopathy patients and 796 controls (type 2 diabetes mellitus patients without diabetic retinopathy); the mean age of all participants was 56.7 +/- 13.9 years. Three single nucleotide polymorphisms were selected: rs507392, rs1617640, and rs551238. The t-test was used for comparison of erythropoietin protein level erythropoietin levels in patients having different erythropoietin genotypes. Logistic regression model was used to examine the association between three single nucleotide polymorphisms and diabetic retinopathy. Odds ratio (OR) and 95% confident interval (95% CI) were calculated. Generalized multifactor dimensionality reduction was employed to analyze the impact of interaction among three single nucleotide polymorphisms on CVD risk. After covariates adjustment, the carriers of homozygous mutant of three single nucleotide polymorphisms have higher diabetic retinopathy risk than those with wild-type homozygotes, OR (95% CI) were 2.04 (1.12-2.35), 1.87 (1.10-2.41) and 1.15 (1.06-1.76), respectively. Generalized multifactor dimensionality reduction model indicated a significant three-locus model (p = 0.0010) involving rs507392, rs1617640, and rs551238. Overall, the three-locus models had a cross-validation consistency of 10 of 10, and had the testing accuracy of 60.72%. Subjects with TC or CC-TG or GG-AC or CC genotype have the highest diabetic retinopathy risk. In conclusion, our results support an important association of rs507392, rs1617640 and rs551238 minor allele of erythropoietin with increased diabetic retinopathy risk, and additional interaction among three single nucleotide polymorphisms.