MTHFR and ischemia: Polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) gene lead to reduced methylation, elevation of Hcy, reduction of nitric oxide, microvascular disease- particularly capillary endothelial injury and apoptosis, microaneurysms, leakage, ischemia, retinal atrophy, neovascularization, and vision loss [22].