Methylenetetrahydrofolate reductase C677T mutation and risk of retinal vein thrombosis

Elevated plasma homocysteine (Hcy) level has been established as a significant risk factor for venous thrombosis and cardiovascular disease. Homozygosity for the methylenetetrahydrofolate reductase (MTHFR) C677T mutation has been associated with elevated plasma Hcy concentration and may contribute to retinal vein thrombosis (RVT) development. The aim of the present study was to investigate whether the hyperhomocysteinemia and/or homozygosity for the MTHFR C677T mutation are associated with an increased risk for RVT. Our study population consisted of 73 consecutive patients (50-78 years old) with RVT and 73 control subjects (51-80 years old), matched for age and sex. Genotyping for the MTHFR C677T mutation was performed by polymerase chain reaction-restriction fragment length polymorphism technique and Hcy level was determined by an enzyme immunoassay kit. The prevalence of 677TT genotype was higher in patients than control subjects, but the difference in frequency didn’t reach a significant value (P = 0.07). The frequency of the 677T allele was 26% and 21.2% in patients and controls, respectively and did not differ significantly between the two groups (odds ratio = 1.3, 95% confidence interval (0.75-2.24), P = 0.33). Fasting plasma total Hcy level was significantly higher in patients than controls (P = 0.001). Our study demonstrated that hyperhomocysteinemia, but not the MTHFR C677T mutation, is associated with RVT.