title: [The association of variable number of tandem repeats polymorphism in the endothelial nitric oxide synthase gene and diabetic retinopathy].
abstract: OBJECTIVE
  To investigate the association between the variable number of tandem repeats (VNTR) polymorphism 4a/b in the endothelial nitric oxide synthase (eNOS) gene and diabetic retinopathy (DR) in patients with type 2 diabetes mellitus.
  
  
  METHODS
  cross-sectional study. A total of 278 type 2 diabetes patients were recruited, of whom 130 had DR, and 148 had diabetes without retinopathy (DWR). Of the 130 patients with DR, 34 had proliferative DR (PDR) and 96 had non-proliferative DR (NPDR). A number of 223 volunteers without diabetes from the same area were recruited as the control group. PCR and agarose gel electrophoresis methods were adopted to determine the 4a/b polymorphism genotypes of the eNOS gene. Statistical analysis was performed using the R statistical analysis package. Genotype distribution was compared using the χ(2) test. Numerical data were examined by Student t test. Genotypes and allele frequencies between cases and controls were compared using the χ(2) test or Fisher's exact test. Odd ratios (OR) and 95% confidence intervals (CI) were calculated according to the Woolf's equation.
  
  
  RESULTS
  The frequencies of minor alleles (a) were 10.8% and 11.5% in the DR and DWR group, respectively. There were no statistical differences between the two groups (χ(2) = 0.07, P = 0.789). Also there were no statistical differences (χ(2) = 0.88; P = 0.643) in the distributions of the genotypes between DR group (bb 78.5%, ab 21.5%, aa 0.0%) and DWR group (bb 77.7%, ab 21.6%, aa 0.7%). Statistical differences were found in the frequencies of alleles, and the distributions of genotypes between diabetes group and the control group (χ(2) = 8.75, 10.39, P = 0.003, 0.006). However, after adjustment for age, blood pressure, cholesterol concentration, blood-fat and so on, it became insignificant (χ(2) = 0.97, 1.25, P = 3.224, 0.812). In the multiple regressions model including clinic factors such as the age of onset of diabetes, urinary albumin, insulin using, creatinine, glycated hemoglobin and fast glucose, no evidence showed that eNOS gene VNTR 4a/b was associated with diabetic retinopathy (OR = 0.37, 95% CI: 0.15-0.95).
  
  
  CONCLUSIONS
  There was no significant association between eNOS gene VNTR 4a/b polymorphism and diabetic retinopathy (DR) in patients with type 2 diabetes mellitus.
authors: Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing 100730, China.
authors: Chongyang
authors: C
authors: She
authors: Xiufen
authors: X
authors: Yang
authors: Hong
authors: H
authors: Gu
authors: Yu
authors: Y
authors: Deng
authors: Jun
authors: J
authors: Xu
authors: Kai
authors: K
authors: Ma
authors: Email: nliu001@gmail.com.
authors: Ningpu
authors: N
authors: Liu
mesh_terms: D000483:Alleles; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2; D003930:Diabetic Retinopathy / Q000235:genetics*; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D018598:Minisatellite Repeats / Q000235:genetics*; D052250:Nitric Oxide Synthase Type III / Q000235:genetics*; D011110:Polymorphism, Genetic
chemical_list: C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III