Genetic polymorphism of the iron-regulatory protein-1 and -2 genes in age-related macular degeneration

Abstract

Iron can be involved in the pathogenesis of AMD through the oxidative stress because it may catalyze the Haber-Weiss and Fenton reactions converting hydrogen peroxide to free radicals, which can induce cellular damage. We hypothesized that genetic polymorphism in genes related to iron metabolism may predispose individuals to the development of AMD and therefore we checked for an association between the g.32373708 G>A polymorphism (rs867469) of the IRP1 gene and the g.49520870 G>A (rs17483548) polymorphism of the IRP2 gene and AMD risk as well as the modulation of this association by some environmental and life-style factors. Genotypes were determined in DNA from blood of 269 AMD patients and 116 controls by the allele-specific oligonucleotide-restriction fragment length polymorphism and the polymerase chain reaction-restriction fragment length polymorphism. An association between AMD, dry and wet forms of AMD and the G/G genotype of the g.32373708 G>A-IRP1 polymorphism was found (OR 3.40, 4.15, and 2.75). On the other hand, the G/A genotype reduced the risk of AMD as well as its dry or wet form (OR 0.23, 0.21, 0.26). Moreover, the G allele of the g.49520870 G>A-IRP2 polymorphism increased the risk of the dry form of the disease (OR 1.51) and the A/A genotype and the A allele decreased such risk (OR 0.43 and 0.66). Our data suggest that the g.32373708 G>A-IRP1 and g.49520870 G>A-IRP2 polymorphisms may be associated with increased risk for AMD.

Fig. 1

Genotypes of the g.32373708 G>A-IRP1 polymorphism (rs867469) determined by the allele-specific oligonucleotide-PCR (ASO-PCR) method and analyzed by a 8% polyacrylamide gel electrophoresis stained with ethidium bromide and viewed under UV light. Lane M displays GeneRuler ^™ 100 bp molecular weight marker, lanes designated G or A show the results of amplification with primer specific to either the G or A allele, respectively and lane X shows a negative control comprising reaction mixture without target DNA. Genotypes are indicated in the lower part of the picture

Fig. 2

Genotypes of the g.49520870 G>A-IRP2 polymorphism (rs17483548) determined by the PCR-RFLP detection and analyzed by a 8% polyacrylamide gel electrophoresis stained with ethidium bromide and viewed under UV light. Lane M shows GeneRuler ^™ 100 bp molecular weight marker, lane X shows a negative control comprising reaction mixture without target DNA, all remaining lanes present genotypes indicated in the upper part of the picture