The variant T of C677T was identified in 60.65% of RVO</span> patients and 59.10% of control subjects, while the variant C of A1298C was present in 46.45% of RVO patients and 51.14% of controls.
Our results suggest that there may be an association between increased risk for RVO and ACE I/D, MTHFR C677T, PAI-1 4G/5G and factor V Leiden polymorphisms, whereas the Val34Leu variant may exert a protective effect.
There was no evidence of association between homozygosity for the MTHFR C677T genotype and RVO (odds ratio [OR] 1.20; 95% CI, 0.84-1.71), but again marked heterogeneity (P = 0.004, I(2) = 53%) was observed.
A prevalence of up to 30% of fasting hyperhomocysteinemia has been recently reported in patients with retinal vein occlusion (RVO) whereas conflicting data exist on the role of C677T polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene as a risk factor for RVO.
Our data suggests that homozygosity for the MTHFR C677T polymorphism is a risk factor of RVO in addition to arterial hypertension and a family history of stroke.