Associations of the genetic polymorphisms in the promoter region and the signal peptide sequence of the transforming growth factor-beta (TGF-beta1) gene with proliferative diabetic retinopathy (PDR) in patients with non-insulin-dependent diabetes mellitus (NIDDM) were studied. A total of 245 Caucasian subjects comprised the two groups: NIDDM patients with PDR (n = 73) and NIDDM patients without PDR (n = 172). Allele frequencies of common TGF-beta1 polymorphisms (at positions -988C/A, -800G/A, -509C/T, +869T/C (L10P), and +915G/C (R25P)) were determined by PCR-based methodology. All polymorphisms were in strong linkage disequilibrium (P < 10(-2)). Significantly higher frequencies of both the L allele and the R allele of the signal sequence polymorphisms in PDR subjects were found (after a correction for multiple comparisons, P(corr) < 10(-2) and P(corr) < 10(-4), respectively). Calculated odds ratios (ORs) for the LL and RR genotypes were 2.89 (95% confidence interval (CI), 1.6-5.1) and 19.73 (95% CI, 2.6-146.8), respectively. No significant differences between groups were found for the -800G/A and -509C/T polymorphisms. The -988A allele was not represented in our sample. Multiple logistic regression identified age, diabetes duration, and R25P polymorphism as significant predictors (P = 0.002, P = 0.000003, and P = 0.007, respectively). The frequencies of genotype combinations of the -800G/A, -509C/T, L10P, and R25P TGF-beta(1) polymorphisms were significantly different between the PDR and non-PDR groups (chi(2) = 37.83, df = 20, P < 10(-2)). The frequency of haplotype consisting of majority alleles was found significantly associated with PDR (P < 0.03). The presented data indicate that the R25P polymorphisms in the TGF-beta1 gene could be regarded as a strong genetic risk factor for PDR.

No abstract

No abstract

The object of the study was to investigate the share of the polymorphisms I/D ACE, endothelin 1 4127G/A and TNF-β NcoI in the susceptibility to proliferative diabetic retinopathy (PDR) in non-insulin-dependent diabetes mellitus (NIDDM). Genotypes were detected by polymerase chain reactions and determined in a set of 246 Caucasian NIDDM subjects with defined PDR status. The relevance of genotypes and clinical characteristics to the PDR occurrence was tested using multiple linear regression models and discrimination analysis. The best predictive value for PDR was given by a combination of two parameters – NIDDM duration and the TNF-β genotype (p < 1·10^–6 and p = 1·10^–2, respectively) with a correct retrograde prediction of 82.6%. A comparison of the TNF-β NcoI allele frequencies revealed no difference between NIDDM and nondiabetic subjects (n = 176), but a statistically significant difference was found between PDR and non-PDR NIDDM subjects (after a correction for the number of comparisons p = 0.03), allele β₂ being associated with PDR. Our results identified the allele variant TNF-β₂ being associated with PDR in NIDDM. Diabetes duration and the TNF-β NcoI genotype were proven to significantly predict PDR occurrence. The TNF-β₂ allele could be regarded as a separate genetic risk factor that increases the relative incidence of PDR in patients with NIDDM.

No abstract