Homocysteine, Methylenetetrahydrofolate Reductase C677T Polymorphism, and Risk of Retinal Vein Occlusion: A Meta-analysis

Abstract

Objective: To assess the role of plasma total homocysteine (tHcy) concentrations and homozygosity for the thermolabile variant of the methylenetetrahydrofolate reductase (MTHFR) C677T gene as risk factors for retinal vascular occlusive disease.Design: Retinal vein occlusion (RVO) is an important cause of vision loss. Early meta-analyses showed that tHcy was associated with an increased risk of RVO, but a significant number of new studies have been published.Participants and/or Controls: RVO patients and controls. Methods: Data sources included MEDLINE, Web of Science, and PubMed searches and searching reference lists of relevant articles and reviews. Reviewers searched the databases, selected the studies, and then extracted data. Results were pooled quantitatively using meta-analytic methods.Main Outcome Measures: tHcy concentrations and MTHFR genotype.Results: There were 25 case-control studies for tHcy (1533 cases and 1708 controls) and 18 case-control studies for MTHFR (1082 cases and 4706 controls). The mean tHcy was on average 2.8 mol/L (95% confidence interval [CI], 1.8 -3.7) greater in the RVO cases compared with controls, but there was evidence of between-study heterogeneity (PϽ0.001, I2 ϭ 93%). There was funnel plot asymmetry suggesting publication bias. 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 ϭ 0.004, I 2 ϭ 53%) was observed. Conclusions: There was some evidence that elevated tHcy was associated with RVO, but not homozygosity for the MTHFR C677T genotype. Both analyses should be interpreted cautiously because of marked heterogeneity between the study estimates and possible effect of publication bias on the tHcy findings.Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

JAK2 mutation status, hemostatic risk factors and thrombophilic factors in essential thrombocythemia (ET) patients

“…Khandanpour et al [18] argued that being homozygous for the MTHFR C677T allele was associated with an increased risk of PAD (peripheral arterial disease). A few months later, McGimpsey et al [19] stated more precisely that retinal vein occlusion was caused by elevated total homocysteine, rather than homozygosity for the MTHFR C677T genotype. We suppose that not only a higher homocysteine level, but also a homozygous mutation of the MTHFR gene, is associated with an increased risk of thrombotic complications.…”

Retinal Vein Occlusion: Current Treatment

“…Open-angle glaucoma or other conditions inducing increased intraocular pressure (IOP) are established local predisposing factors [11]. However, there are other risk factors that are related to hemostasis, such as hyperhomocysteinemia; these are more commonly related to CRVO [9,12,13]. …”

Retinal Vein Occlusion and Polymorphisms

“…Çalışma sonunda PT, FVL ve MTHFR insidansında iki grup arasında fark bulunamasa da GpIa/IIa polimorfizmlerinin RVT patogenezinde major bir rol oynayabileceğini ileri sürmüşlerdir [23]. Marucci ve arkadaşları MTHFR polimorfizmlerini değerlendirmişler ve homozigot C677T MTHFR genotip RVT olan hastalarda önemli şekil-de yüksek bulmuşlardır [24]. McGimpsey ve arkadaşlarının yaptığı bir meta-analiz çalışmasında homozigot MTHFR C677T'nin retinal ven tıkanıklığı için bir risk oluşturmadığı tespit edilmiş-tir [25].…”