Abstract
Purpose: :
Diabetic retinopathy is a common complication of diabetes involving the development of new blood vessels from retinal circulation. Recent findings suggest that peroxisome proliferators activated receptor gamma (PPARG) ligands inhibit intraocular angiogenesis. Moreover polymorphisms of this nuclear receptor have been associated with type–2 diabetes. We investigated whether Pro12Ala and C1431T PPARG variants could be a risk factor for proliferative retinopathy.
Methods: :
A case–control study was performed in diabetic patients from South Italy. The diabetic subjects were from separate families and gave written consent to participate for further biochemical and genetic analysis. Patients were eligible for the study if they had background (mild) or proliferative (severe) diabetic retinopathy, similar age and similar duration of diabetes. Retinopathy was assessed with the aid of fundusphotography and fluoroangiography. The polymorphisms were determined by PCR followed by direct sequencing. A Chi–square test was performed and a P value <0.05 was considered as statistically significant.
Results: :
We analyzed the allele frequencies in type 2 diabetic patients, 45 with mild retinopathy and 45 with severe. The Pro12Ala polymorphism was detected in 15.6% of the total sample; more precisely 17.8% belonged to the mild group and 13.3% were from the mild. Similar percentages were found for the C1431T variant. Slight differences were observed between the two groups: 15.6% C/T subjects in the mild group and 17.8% in the severe. Small differences were also observed in the two groups of patients when analyzed in detail for the different genotypes. Generally the haplotypes containing at least one rare allele were more represented in the severe group than in the mild one, whereas the frequent haplotype Pro12C1431, was less represented in the severe group (71.1%) than in the mild one (80.0%). However, these differences are not considered significant.
Conclusions: :
No study has addressed the relationship between severe retinopathy and variation in the incidence of 2 polymorphisms. We found no differences in the allele frequencies of Pro12Ala and C1431T variants between patients with mild retinopathy and patients with severe. These data leading to the conclusion that these polymorphisms are not associated with the prevalence of proliferative retinopathy in type 2 diabetic patients.
Keywords: diabetic retinopathy • genetics • gene screening