Abstract
Purpose: :
An association has been previously reported between primary open-angle glaucoma (POAG) and a polymorphism within the Nitric Oxide Synthase 3 (NOS3) gene. This gene is involved in regulating aqueous humor dynamics, local modulation of ocular blood flow and may control retinal ganglion cell death by apoptosis. We evaluated the role of a functional polymorphism within NOS3 and susceptibility to POAG in a Caucasian population recruited at the West Virginia University Eye Institute.
Methods: :
Subjects were classified after a comprehensive ophthalmologic examination. Blood samples were collected after obtaining informed consent. Genotypes were obtained for 200 unrelated Caucasian POAG patients and 165 controls for the rs1799983 polymorphism (Glu298Asp) within NOS3 by amplification by PCR and restriction enzyme digestion (BfuCI).
Results: :
Chi-square analysis detected a significant difference in genotypic frequencies between POAG cases and controls (Χ2=6.24, p=0.03). We observed an increase in the frequency of homozygote carriers of the Asp allele in POAG cases compared to controls (0.15 vs. 0.08). Homozygosity for the Asp allele was associated with a significant 2-fold increased risk of developing POAG (95% CI: 1.12-4.52, p=0.03). Interestingly, the association appeared to be stronger in men (OR=2.5, 95% CI: 0.89-7.3) than women (OR=1.5, 95% CI: 0.55-4.01).
Conclusions: :
Our preliminary results indicate that homozygosity for the Asp allele within NOS3 is associated with susceptibility to POAG in our sample. We will continue to expand this finding and will examine additional polymorphisms within NOS3 that may be part of a haplotype that is associated with increased risk of developing POAG.
Keywords: genetics • candidate gene analysis • nitric oxide