title: Lack of association between polymorphisms of the DNA base excision repair genes MUTYH and hOGG1 and keratoconus in a Polish subpopulation.
abstract: BACKGROUND
  Keratoconus (KC) is a non-inflammatory thinning of the cornea and a leading indication for corneal transplantation. Oxidative stress plays a role in the pathogenesis of this disease. The products of the hOGG1 and MUTYH genes play an important role in the repair of oxidatively modified DNA in the base excision repair pathway. We hypothesized that variability in these genes may change susceptibility to oxidative stress and predispose individuals to the development of KC. We investigated the possible association between the c.977C>G polymorphism of the hOGG1 gene (rs1052133) and the c.972G>C polymorphism of the MUTYH gene (rs3219489) and KC occurrence as well as the modulation of this association by some KC risk factors.
  
  
  METHODS
  A total of 205 patients with KC and 220 controls were included in this study. The polymorphisms were genotyped with polymerase chain reaction (PCR) restriction fragment length polymorphism and PCR-confronting two-pair primer techniques. Differences in genotype and allele frequency distributions were evaluated using the χ(2) test, and KC risk was estimated with an unconditional multiple logistic regression with and without adjustment for co-occurrence of visual impairment, allergies, sex and family history for KC.
  
  
  RESULTS
  We did not find any association between the genotypes and combined genotypes of the c.977C>G polymorphism of the hOGG1 gene and the c.972G>C polymorphism of the MUTYH gene and the occurrence of KC.
  
  
  CONCLUSIONS
  Our findings suggest that the c.977C>G-hOGG1 polymorphism and the c.972G>C-MUTYH polymorphism may not be linked with KC occurrence in this Polish subpopulation.
authors.affiliation: Department of Molecular Genetics, University of Lodz, Lodz, Poland.
authors.forename: Ewelina
authors.initials: E
authors.lastname: Synowiec
authors.affiliation: Department of Molecular Genetics, University of Lodz, Lodz, Poland.
authors.forename: Katarzyna A
authors.initials: KA
authors.lastname: Wójcik
authors.affiliation: Department of Molecular Genetics, University of Lodz, Lodz, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Czubatka
authors.affiliation: Department of Ophthalmology, Medical University of Warsaw, SPKSO Ophthalmic University Hospital, Warsaw, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Polakowski
authors.affiliation: Department of Ophthalmology, Medical University of Warsaw, SPKSO Ophthalmic University Hospital, Warsaw, Poland.
authors.forename: Justyna
authors.initials: J
authors.lastname: Izdebska
authors.affiliation: Department of Ophthalmology, Medical University of Warsaw, SPKSO Ophthalmic University Hospital, Warsaw, Poland.
authors.forename: Jerzy
authors.initials: J
authors.lastname: Szaflik
authors.affiliation: Department of Molecular Genetics, University of Lodz, Lodz, Poland.
authors.forename: Janusz
authors.initials: J
authors.lastname: Błasiak
authors.affiliation: Department of Ophthalmology, Medical University of Warsaw, SPKSO Ophthalmic University Hospital, Warsaw, Poland.
authors.forename: Jacek P
authors.initials: JP
authors.lastname: Szaflik
keywords: DNA glycosylases; DNA repair; genetic variability; oxidative DNA damage; oxidative stress