Polymorphism is a DNA sequence variation. It usually does not cause overt debilitating diseases, but may contribute to disease susceptibility and influence drug responses. For example, the single nucleotide polymorphism (SNP) of tumor necrosis factor-? (TNF-?) has been shown to play a role in the pathogenesis of primary open-angle glaucoma (POAG) and increase the risk for developing Alzheimer?s disease (AD). Both glaucoma and AD are irreversible neurodegenerative diseases that usually affect the elderly group and inflammatory mechanisms are the relevant etiological factors for these two diseases. Based on the potential similarities between glaucoma and AD, the main purpose of the present study was to investigate the possible associations between the gene polymorphisms of AD related inflammatory cytokines, such as TNF-? (-865), TNF-? (-859), TNF-?(-1032) or IL-6 (-174), and the development of glaucoma.
Subjects were recruited from the outpatient clinic in the Department of Ophthalmology at the Veterans General Hospital, Taichung, Taiwan. All participants received comprehensive ophthalmologic examinations and then were divided into glaucoma (POAG and normal tension glaucoma; NTG) and normal control groups. Genotyping for polymorphisms in TNF-? (-865) C/A, TNF-? (-859) G/A, TNF-? (-1032) T/C, and IL-6 (-174) C/G genes were performed using polymerase chain reactions.
Results indicated that the distribution of the TNF-??(-1032) T allele (TT genotype) was greater in the POAG patients as compared to the control subjects (P=0.01009). However, no clear association was present between the gene polymorphisms in TNF-? (-865) C/A, TNF-? (-859) G/A, or IL-6 (-174) C/G and glaucoma. Therefore, it is concluded that the TNF-? (1032) T allele polymorphism might be a risk factor in the development of POAG.
