Association of endothelial nitric oxide synthase (NOS3) gene polymorphisms with primary open-angle glaucoma in a Saudi cohort

AIM: To investigate the association of endothelial nitric oxide synthase (NOS3) gene polymorphisms in patients with primary open-angle glaucoma (POAG) of Saudi origin. METHODS: This case-control study included 173 patients with POAG (94 men and 79 women) and 171 controls (98 men and 73 women). Genotyping of rs2070744 (T-786C) and rs1799983 (G894T) variants of the NOS3 gene was performed using TaqMan(®) assay. RESULTS: Rs1799983 genotypes showed a significant association with POAG but did not survive Bonferroni correction (p(correction) = 0.01). The minor ‘T’ allele was significantly associated with the risk of POAG among men (p = 0.025, odds ratio (OR) = 1.77, 95% confidence interval (CI) = 1.07–2.94). Likewise, the genotypes were significantly associated with POAG among men in dominant (p = 0.030, OR = 1.92, 95% CI = 1.06–3.48) and log-additive models (p = 0.022, OR = 1.82, 95% CI = 1.08–3.07), and after adjustment for age and smoking. Genotype and allele frequencies of rs2070744 were not significantly different between POAG cases and controls, and after sex stratification. CG haplotype was significantly protective (p = 0.011, OR = 0.52, 95% CI = 0.32–0.87) and CT haplotype conferred significantly increased risk of POAG (p = 0.016, OR = 2.60, 95% CI = 1.16–5.82) among men. Rs1799983 showed trend (p = 0.054) towards risk of POAG independent of age, gender, smoking, and rs2070744 polymorphism in logistic regression analysis. Both the polymorphisms showed no association with POAG phenotypes such as intraocular pressure and cup/disc ratio. CONCLUSION: Our results suggest that the polymorphism rs1799983 and the haplotypes of rs20707440 and rs1799983 in the NOS3 gene may significantly modulate the risk of POAG in Saudi’s, particularly among men. Further larger studies are needed to confirm these findings.