The A Allele of the -576G>A Polymorphism of the Transferrin Gene Is Associated with the Increased Risk of Age-Related Macular Degeneration in Smokers

Age-related macular degeneration (AMD) is the leading cause of blindness among the elderly in developed countries, and its pathogenesis is underlined by genetic and environmental factors. Oxidative stress is a major environmental risk factor of AMD; namely, AMD is associated with the increased level of reactive oxygen species, which may be produced in reactions catalyzed by iron present in the retina. Therefore, variability of the genes of iron metabolism may be important in the AMD risk. In the present study, we analyzed the association between AMD and the -576G>A polymorphism of the transferrin gene or the 1892C>T polymorphism of the transferrin receptor 2 (TFR2) gene in 278 patients with AMD and 105 controls. The former polymorphism is located in the promoter region of the transferrin gene and may affect the level of its transcription, while the latter is a synonymous mutation in the exon 16, which may affect the efficiency of translation of TFR2 mRNA. Transferrin and TFR2 are important in iron homeostasis. The A allele of the -576A>G polymorphism was significantly associated with the increased risk of AMD in tobacco smokers, whereas the 1892C>T polymorphism did not influence the risk of AMD related to smoking. Moreover, each polymorphism does not influence the risk of AMD associated with age, sex or the family history of the disease. In conclusion, the A allele of the -576A>G polymorphism of the transferrin gene may increase the risk of AMD in smokers.