Can Heterozygosity of MTHFR and Hyperhomocysteinemia be Risk Factors for Both Retinal/Vitreal Hemorrhages in Retinal Vasculitis and Retinal Vein Occlusion?

Abstract

Retinal vein occlusion (RVO) is one of the most common vascular diseases of the eye and a frequent cause of severe visual loss. It is multifactorial in origin with both local factors and systemic diseases being of etiological importance. Many thrombophilic conditions have recently been identified and studies looking at their potential role in RVO have been undertaken. The aim of this study was to investigate the role of methylenetetrahydrofolate reductase (MTHFR) heterozigosity associated with normal homocysteine level in blood as risk factor for thromboembolic retinal/vitreal manifestations in patients with retinal vasculitis (RV) and RVO where the other risk factors (such as hypertension; atherosclerosis; diabetes; antiphospholipid syndrome) are excluded. Second question was if anticoagulation treatment should be applied together with systemic corticosteroids and/ immunosuppressive therapy? Results obtained from the examined group showed that heterozigosity for MTHFR C677T gene is of statistical significance and correlates with raised values of homocysteine (correlation coefficient = 0.23). At the same time increased levels of homocysteine correlate (correlation coefficient = 0.01) with appearance of RVO. At r = 0.67, if there is no RV present, existence of a single mutated allele for MTHFR C677T gene does not correlate with RVO. There is however significant correlation between the mutation for MTHFR and hemorrhagic type of RV associated with RVO and/ with isolated hemorrhagic vasculitis without RVO (correlation coefficient = 0.33; correlation coefficient = 0.27; respectively).

Investigation of methylenetetrahydrofolate reductase C677T and factor V Leiden mutation as a genetic marker for retinal vein occlusion

“…Paovic et al . [ 17 ] showed that patients with CT genotype of MTHFR C677T polymorphism had raised values of homocysteine that correlated with causation of RVO. The authors further concluded that in the absence of retinal vasculitis, the existence of a single-mutated allele for MTHFR C677T gene did not correlate with RVO.…”

“…[ 18 ] There can be many causes for hyperhomocysteinemia, besides genetic mutations, such as vitamin deficiencies (pyridoxine, folic acid, and Vitamin B12), chronic illnesses (chronic renal failure, diabetes, hypertension, and cancer), drugs (methotrexate, antiepileptic agents), and enzyme deficiencies. [ 17 ]…”