title: GSTT1 null genotype is a risk factor for diabetic retinopathy in Caucasians with type 2 diabetes, whereas GSTM1 null genotype might confer protection against retinopathy.
abstract: OBJECTIVE
  Substantial data indicate that oxidative stress is involved in the development of diabetic retinopathy (DR). The aim of the present study was to investigate whether the genetic polymorphisms: polymorphic deletions of glutathione S-transferases M1 (GSTM1) and T1 (GSTT1) and Ile105Val of the GSTP1 are associated with DR in Slovenian patients with type 2 diabetes.
  
  
  METHODS
  In this cross sectional case-control study 604 unrelated Slovene subjects (Caucasians) with type 2 diabetes mellitus were enrolled: 284 patients with DR (cases) and the control group of 320 subjects with type 2 diabetes of more than 10 years' duration who had no clinical signs of DR. Genotypes were determined by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP).
  
  
  RESULTS
  In our study, the deletion of the GSTM1 was found less frequent in cases with DR than in the controls (27.5% versus 44.4%; P < 0.001), whereas the deletion of GSTT1 was found significantly more often in cases than in the controls (49.3% versus 29.7%; P < 0.001). We did not find statistically significant differences in the genotype distribution in GSTP1 (Ile105Val) polymorphism between cases and controls (40.5% versus 46.0%).
  
  
  CONCLUSIONS
  We may conclude that individuals homozygous for the deletion of GSTT1 are at an ≈ 2-fold-greater risk of DR, whereas the GSTM1 deficiency is associated with lower frequency of DR in type 2 diabetics.
authors.affiliation: Institute of Histology and Embryology, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Ines
authors.initials: I
authors.lastname: Cilenšek
authors.forename: Sara
authors.initials: S
authors.lastname: Mankoč
authors.forename: Mojca Globočnik
authors.initials: MG
authors.lastname: Petrovič
authors.forename: Daniel
authors.initials: D
authors.lastname: Petrovič
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000235:genetics; D003930:Diabetic Retinopathy / Q000235:genetics*; D005260:Female; D017353:Gene Deletion; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D005838:Genotype; D051549:Glutathione S-Transferase pi / Q000235:genetics; D005982:Glutathione Transferase / Q000235:genetics*; D006720:Homozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D020125:Mutation, Missense; D012307:Risk Factors; D044465:White People
chemical_list: D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase; C413545:glutathione S-transferase T1; C496556:GSTP1 protein, human