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

Abstract

PURPOSE:Thromboembolic phenomenon is one of the causes of retinal vein occlusion (RVO) which is in fact a multifactorial disease. Therefore, we aimed to study methylenetetrahydrofolate reductase gene polymorphism (MTHFR C677T) and factor V Leiden as genetic risk factors of RVO.MATERIALS AND METHODS:A total of 50 (19 males and 31 females) cases of RVO were compared with 50 age- and sex-matched (21 males and 29 females) controls. Complete ocular examination was done for all samples. The diagnosis of RVO was made clinically; however, fundus fluorescein angiography and optical coherence tomography were performed when needed. Serum homocysteine levels were estimated by automatic chemiluminescence analyzer, whereas MTHFR C677T and factor V Leiden mutations were detected by polymerase chain reaction–restriction fragment length polymorphism method.RESULTS:The mean age of RVO cases and controls was 54.62 ± 13.92 years and 58.72 ± 11.20 years, respectively. 48.3% of cases and 51.7% of controls were diabetic. 65.3% of cases were hypertensive proving hypertension as a strong risk factor (P = 0.003) of RVO. Serum homocysteine was also found significantly high (P = 0.025) with mean values of 19.98 ± 9.03 μmol/L and 16.98 ± 8.29 μmol/L in cases and controls, respectively. The MTHFR genotype (CT) was found in 83.3% patients of central RVO group and 78.6% cases of branch RVO group that was significantly associated with high serum homocysteine levels. Factor V Leiden mutation was absent in all individuals.CONCLUSION:Hyperhomocysteinemia is an important risk factor for RVO, especially in patients with MTHFR C677T gene polymorphism.