Abstract
Abstract: :
Purpose: Expression of the endothelial Nitric Oxide Synthase (eNOS) gene has been reported in the eye and some alterations of the NO system have been found in human eyes with glaucoma. Here we examine the frequency of eNOS T-786-C and G894-T polymorphisms in POAG patients and in normal controls. Methods: Peripheral blood samples were collected from 53 consecutive POAG patients and from 66 healthy controls with no history of glaucoma. Subjects with diabetes, cardiovascular pathology or other ocular diseases were not enrolled in the study. ENOS polymorphisms were studied by means of polymerase chain reaction followed by restriction enzyme digestion. Results: Regarding the T-786-C alteration, in POAG we found a higher frequency of the C allele than in controls, even if the difference was not statistically significant. However, the two groups significantly differed in genotype distribution, being the heterozygous CT genotype more common in glaucoma patients (p= 0.003). As much as it concerns the G894-T polymorphism, this was more frequent in glaucoma subjects than in normals, even if the difference between the two groups did not attain statistical significance. The odds ratio of allele frequencies showed a significant association between the presence of eNOS 786C allele and POAG (OR= 2.7, p= 0.009), while the presence of the G894-T alteration could not be related to the disease (OR= 1.16, p= 0.73). Conclusion: Our data indicate an increased risk of POAG in carriers of the eNOS 786C allele. This gene variant has been reported to reduce the NO production suppressing the eNOS gene transcription. Decreased eNOS concentration in tissues with altered NO levels could influence both optic nerve circulation and aqueous humor hydrodynamics.
Keywords: 420 genetics • 491 nitric oxide • 358 clinical laboratory testing