MTHFR C677T mutation in central retinal vein occlusion: a case-control study in Chinese population

Hemicentral retinal vein occlusion in a patient with a history of coronavirus disease 2019 infection: a case report and review of the literature

BACKGROUND

Considering the various manifestations of coronavirus disease 2019 and its imperative importance in terms of the right clinical approach and early management, we sought to present a hemicentral retinal vein occlusion case, with a history of heterozygosity of methylenetetrahydrofolate reductase (MTHFR) genes and potential for clotting complications as a late manifestation of coronavirus disease 2019, and provide a brief review of reported retinal vein occlusion cases in patients with coronavirus disease 2019.

CASE PRESENTATION

A 35-year-old Iranian patient presented with a visual impairment in the left eye 4 months after recovering from coronavirus disease 2019. He reported a mild blurring of vision in the same eye a few days after admission due to coronavirus disease 2019. The ophthalmic evaluation was compatible with hemicentral retinal vein occlusion. Systemic and laboratory workups were negative except for borderline protein C activity, homocysteine levels, and heterozygosity of MTHFR genes. The patient was scheduled to receive three monthly intravitreal antivascular endothelial growth factor injections.

CONCLUSION

We present a case of inferior hemicentral retinal vein occlusion case with an MTHFR mutation with sequential loss of vision 4 months after coronavirus disease 2019 to make clinicians aware of the possibility of late ocular coronavirus disease 2019 manifestations.

CENTRAL RETINAL VEIN OCCLUSION IN 12-YEAR-OLD GIRL WITH METHYLENETETRAHYDROFOLATE REDUCTASE MUTATION: A CASE REPORT AND REVIEW OF THE LITERATURE

PURPOSE

This case report describes a central retinal vein occlusion in a healthy 12-year-old girl who developed retinal neovascularization at 24 years of age. To the knowledge of the authors, this is the longest time between a reported pediatric central retinal vein occlusion event and neovascularization.

METHODS

The patient underwent a full history, physical examination, and laboratory workup to determine potential risk factors contributing to the vascular event. Fundus photographs, optical coherence tomography, and fluorescein angiography were performed throughout the patient's treatment course.

RESULTS

Family history was noncontributory, but laboratory testing revealed a mildly elevated homocysteine level and homozygous C677T mutation in methylenetetrahydrofolate reductase. As a result, she was started on folate supplementation. The patient has had no further ocular or systemic thrombotic events to date.

CONCLUSION

Pediatric patients presenting with central retinal vein occlusion should undergo a systemic workup and require long-term follow-up to avoid complications, such as intraocular hemorrhage, tractional retinal detachments, and neovascular glaucoma.

Prevalence of homocysteinemia and effect of vitamin supplementation in retinal vein occlusion

Objective

The objective of this study was to determine the prevalence of homocysteinemia in patients with retinal vein occlusion (RVO). We investigated the association of B complex vitamin (BCV) and multivitamin (MVI) supplementation on homocysteine levels in RVO patients.

Methods and analysis

This cross-sectional study occurred at the Retina Center of New Jersey. We investigated 312 patients diagnosed with RVO between 2011 and 2019. Homocysteine levels were measured on diagnosis of RVO and 4–8 weeks after, following recommended daily supplementation with BCV, MVI or combination MVI+BCV.

Results

The median patient age was 71.00, IQR (61.00, 78.25), with 164 (52.6%) being women. Prevalence of homocysteinemia (>13 µmol/L) was 150 of 312 (48.1%), with a median baseline homocysteine level of 12.80 (10.17, 15.90) µmol/L. The follow-up cohort, 105 patients, demonstrated significant reduction in median homocysteine levels from 14.50 (12.30, 17.90) to 10.70 (9.30, 13.50) µmol/L following vitamin supplementation. Multivariate analysis found having baseline homocysteinemia was significantly associated with at least 25% reduction in homocysteine following vitamin supplementation.

Conclusions

In this study, 48.1% of patients with RVO had elevated homocysteine (>13 µmol/L). Supplementation with BCV or MVI+BCV was associated with a significant reduction in homocysteine from 14.50 (12.30, 17.90) to 10.70 (9.30, 13.50) µmol/L.

Effects of individualized administration of folic acid on prothrombotic state and vascular endothelial function with H-type hypertension: A double-blinded, randomized clinical cohort study

BACKGROUND

Hypertension and hyperhomocysteinemia (HHcy) have long been associated with adverse cardiovascular and cerebrovascular health outcomes. This study evaluated the effect of individualized administration of folic acid (FA) on homocysteine (Hcy) levels, prothrombotic state, and blood pressure (BP) in patients with H-type hypertension (combination of HHcy and hypertension).

METHODS

In this double-blinded, randomized clinical cohort study, 126 patients with H-type hypertension who were treated at our hospital were randomly divided into treatment and control groups (n = 55 each). The control group was treated with oral levamlodipine besylate tablets 2.5 mg and placebo, once a day (in the morning). The treatment group was first treated with oral levamlodipine besylate 2.5 mg and FA tablets 0.8 mg, once a day (in the morning), for 12 weeks. Then, in a second 12-week phase, the FA dose was adjusted using the methylene tetrahydrofolate reductase C677 polymorphism genotype. The levels of Hcy and coagulation factors, prothrombotic state parameters, BP, and adverse drug reactions were compared between the 2 groups.

RESULTS

Pretreatment general patient characteristics, including Hcy levels, were similar between the 2 groups (P > .05). BP and prothrombotic status did not differ before and after the first phase of treatment (P > .05). However, Hcy and endothelin-1 (ET-1) levels decreased, while nitric oxide levels increased significantly in the intervention group (P < .05). In the second phase, after 3 months' treatment with an FA dose adjusted according to methylene tetrahydrofolate reductase C677T genotype, the Hcy and ET-1/NO levels were significantly decreased in the intervention group and were lower than those after the first treatment phase and lower than in the control group (P < .01). BP, D-dimer levels, and fibrinogen scores were significantly lower after the second treatment phase (P < .01). There was no significant difference in the incidence of adverse drug reactions between the 2 groups (P > .05).

CONCLUSIONS

Individualized administration of FA tablets can effectively reduce BP, and Hcy and coagulation factor levels, and significantly improve prothrombotic status in patients with H-type hypertension.

Methylenetetrahydrofolate reductase polymorphisms as risk factors for retinal venous occlusive disease: A literature review

The role of polymorphisms of methylenetetrahydrofolate reductase (MTHFR) gene in retinal vein occlusion (RVO) is a theme of discussion since the first reports of RVO in patients with MTHFR C677T mutation and without classic acquired risk factors for retinal vascular disease. The association between MTHFR polymorphisms and RVO has been studied over the last 20 years producing conflicting results. This review aims to summarize the literature concerning the role MTHFR polymorphisms as risk factors for RVO.

Meta-analysis of the relationship between methylenetetrahydrofolate reductase C677T and A1298C polymorphism and venous thromboembolism in the Caucasian and Asian

Recent years, it is a highly debated topic that whether methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and A1298C polymorphism could increase susceptibility to venous thromboembolism (VTE) in the Asian and Caucasian. Therefore, we expect to settle that controversy evidentially. Basic methods: Electronic databases (Pubmed, embase, Cochrane library, scopus, OvidSP, Wiley Online library, Springer link, EBSCO, Elsevier Science Direct, Google scholar) without date limitation were searched. Crude odds ratio (OR) along with 95% confidence interval (95% CI) was calculated to assess the association quantitatively. Finally, a total of 37 eligible studies were included, containing 31 for MTHFR C677T polymorphism and 6 for MTHFR A1298C polymorphism. The pooled results suggested that MTHFR C677T mutation may increase susceptibility to VTE in reverse recessive model (CC+CT vs TT): OR = 0.68 (0.56, 0.83), reverse dominant model (CC vs CT +TT): OR = 0.82 (0.72, 0.94), heterozygote model (CT vs TT): OR = 0.65 (0.52, 0.81), homozygote model (CC vs TT): OR = 0.73 (0.60, 0.89) and allele model (C vs T): OR = 0.80 (0.71, 0.90). Subgroup analysis about Asian also support that results, but Caucasian group not. In addition, MTHFR A1298C polymorphism may be not related to VTE in all genetic model. The results of meta-analysis indicated that MTHFR C677T polymorphism might increase the risk of VTE, especially in Asian population.

Association of retinal vein occlusion, homocysteine, and the thrombophilic mutations in a Turkish population: A case-control study

PURPOSE

To compare homocysteine and thrombophilic mutations for the methylenetetrahydrofolate reductase (MTHFR) C677T, factor V Leiden, and prothrombin G20210A between retinal vein occlusion (RVO) and healthy controls in a Turkish population.

MATERIALS AND METHODS

Forty-nine subjects with RVO were compared for homocysteine status and the MTHFR C677T, prothrombin G20210A, and factor V Leiden mutations with those of 68 healthy controls. Then, the groups were subdivided into two subgroups according to age (less than 50 years old, equal to or more than 50 years old) and were further compared.

RESULTS

Mean plasma level of homocysteine was similar, but the frequency of hyperhomocysteinemia was significantly higher in the RVO group when compared with the control group (22.5% and 8.8%, respectively, p = 0.037). The frequency of all thrombophilic mutations was similar between the groups (p > 0.05). The frequency of all thrombophilic mutations and homocysteine levels was also similar between age subgroups (p > 0.05). Only hyperhomocysteinemia was significantly different between subgroups (p = 0.037); the frequency of hyperhomocysteinemia was significantly different in RVO patients less than 50 years old (22.7%) from that in healthy controls less than 50 years old (11.1%). Two RVO patients (4.1%) with bilateral involvement had MTHFR C677T mutation.

CONCLUSIONS

Screening for thrombophilic mutations such as MTHFR C677T, factor V Leiden, and prothrombin G20210A in RVO patients at all ages seems to be unnecessary and not cost-effective. However, thrombophilic disorders should be screened selectively, focusing on young individuals, especially with bilateral involvement, without additional cardiovascular risk factors, or a family history of thrombosis.

Role of Hyperhomocysteinemia and Methylene Tetrahydrofolate Reductase C677T Polymorphism in Idiopathic Portal Vein Thrombosis

Purpose:

Portal vein thrombosis (PVT) is a rare and life-threatening vascular disorder characterized by obstruction or narrowing of the portal vein. Hyperhomocysteinemia and methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism has been studied in PVT patients with conflicting results. In the present study the association of hyperhomocysteinemia and MTHFR C677T polymorphism with PVT risk was investigated in Iranians.

Materials and Methods:

Our study population consisted of 10 idiopathic PVT patients and 80 healthy control subjects matched for age and sex. MTHFR C677T polymorphism was genotyped by the polymerase chain reaction technique combined with restriction enzyme fragment length polymorphism (PCR-RFLP) technique and plasma total homocysteine (tHcy) levels were determined by enzyme immunoassay method.

Results:

Mean plasma tHcy levels were significantly higher in PVT patients (20.2±6.8) than control subjects (10.9±4.7) (P=0.001). Moreover, plasma tHcy levels were significantly higher in 677T allele carriers relative to 677C allele carriers in both PVT patients (P=0.01) and control subjects (P=0.03). Neither homozygote nor heterozygote genotypes of MTHFR C677T polymorphism correlated significantly with PVT risk (P>0.05). Moreover, MTHFR C677T polymorphism didn’t increase the risk of PVT under dominant (CT+TT vs. CC) or recessive (TT vs. CC+CT) genetic models analyzed (P>0.05). The difference in frequency of minor 677T allele between PVT patients and control subjects was not statistically significant (P>0.05).

Conclusion:

Based on the current study, we suggest that hyperhomocysteinemia constitutes a significant and common risk factor for PVT. Also, MTHFR C677T polymorphism is not a risk factor for PVT but is a contributing factor for elevated plasma tHcy levels.

Preservation of retinal structure and function after cilioretinal artery occlusion: a case report

Cilioretinal artery occlusion is a cause of sudden, often catastrophic loss of central vision. There are no established effective treatments. Recently, a patient presented 24 hours after a cilioretinal artery occlusion, following a cardiac catheterization prior to which her blood thinners had been discontinued. Lacking an effective way to address the severe retinal ischemic oxidative stress, she was offered, under compassionate use, a multivitamin complex designed to address retinal ischemia and oxidative stress. Significant components of this product are L-methylfolate and n-acetyl cysteine. The patient experienced a rapid unexpected improvement in vision and preservation of retinal structure, suggesting that marked improvement in retinal artery occlusions outcomes may be possible as late as 24 hours postocclusion. This is the third reported case of cilioretinal artery occlusion associated with cardiac catheterization.

Hyperhomocysteinemia, a biochemical tool for differentiating ischemic and nonischemic central retinal vein occlusion during the early acute phase

PURPOSE

The purpose of the study was to differentiate ischemic central retinal vein occlusion (CRVO) from nonischemic CRVO during the early acute phase using plasma homocysteine as a biochemical marker.

METHODS

Fasting plasma homocysteine, serum vitamin B12, and folate levels were measured in 108 consecutive unilateral elderly adult (age >50 years) ischemic CRVO patients in the absence of local and systemic disease and compared with a total of 144 age and sex matched nonischemic CRVO patients and 120 age and sex matched healthy control subjects.

RESULTS

Homocysteine level was significantly increased in the patients with ischemic CRVO in comparison with nonischemic CRVO patients (p = 0.009) and also in comparison with control subjects (p < 0.001). Analysis also showed that hyperhomocysteinemia was associated with increased incidence of ischemic CRVO (odds ratio, 18) than that for nonischemic CRVO (odds ratio, 4.5). Serum vitamin B12 and folate levels were significantly lower (p < 0.001) in CRVO patients compared to the control but were not significantly different between nonischemic and ischemic CRVO patients (p > 0.1).

CONCLUSIONS

Hyperhomocysteinemia can be regarded as useful in differentiating nonischemic and ischemic CRVO during the early acute phase in absence of local and systemic disease in the elderly adult (age >50 years) population.

Association between MTHFR C677T polymorphism and venous thromboembolism risk in the Chinese population: a meta-analysis of 24 case-controlled studies

The association between methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and venous thromboembolism (VTE) risk in the Chinese population has been widely reported, but results were inconsistent and underpowered. To elucidate the variable results, a meta-analysis and systematic review were performed from all case-controlled studies relating MTHFR C677T polymorphism by pooling data on them. We estimated the pooled odds ratio with its 95% confidence intervals to assess this possible association. Finally, a total of 24 studies with 2339 cases and 4048 controls were included in the current meta-analysis. Significant association was found with VTE risk for all genetic models. Subgroup analyses by type of VTE further identified the above-mentioned association in deep vein thrombosis/pulmonary embolism and splanchnic vein thrombosis. The findings from our meta-analysis support the associations of MTHFR C677T polymorphism with VTE risk in the Chinese population.

Genetic polymorphisms associated with retinal vein occlusion: a Greek case-control study and meta-analysis

BACKGROUND

The genetic background of retinal vein occlusion (RVO) remains unclear. In the current study, we aimed to replicate polymorphisms related to thrombophilia/hypofibrinolysis in a Greek population and also systematically summarize current evidence available on the topic.

MATERIALS AND METHODS

A total of 48 RVO patients and 53 controls were genotyped for factor V H1299R and V Leiden, β-fibrinogen G455A, PAI-1 4G/5G, ACE I/D, HPA1, prothrombin G20210A, factor XIII Val34Leu, MTHFR A1298C and C677T polymorphisms. We examined the association between RVO and the above polymorphisms under a per-allele genetic model in a Greek unrelated case/control population. Additionally, searching PubMed up to January 2012, we identified existing evidence on these polymorphisms and performed meta-analyses.

RESULTS

A total of three polymorphisms had nominally significant associations with RVO. These associations pertained to ACE D allele (odds ratio, OR, 2.08 [95% CI, 1.12-3.85], p = 0.02); factor XIII 34Leu allele (OR = 0.41 [95% CI, 0.18-0.95], p = 0.037] and MTHFR 677T variant (OR = 2.20 [95% CI 1.10-4.40], p = 0.026). We performed a meta-analysis on the associations between RVO and PAI-1 (n = 5), factor V Leiden (n = 21), MTHFR C677T (n = 19) and prothrombin G20210A (n = 21). We observed nominally significant associations only for PAI-1 (OR = 1.27 [95% CI, 1.02-1.60, p = 0.036]) (I(2) = 44.7%), and factor V Leiden (OR = 1.40 [95% CI, 1.07-1.84, p = 0.015]) (I(2) = 3.6%) using random effects model.

CONCLUSIONS

Our results suggest that there may be an association between increased risk for RVO and ACE I/D, MTHFR C677T, PAI-1 4G/5G and factor V Leiden polymorphisms, whereas the Val34Leu variant may exert a protective effect.

Association of the functional polymorphism C677T in the methylenetetrahydrofolate reductase gene with colorectal, thyroid, breast, ovarian, and cervical cancers

BACKGROUND

Polymorphisms of the gene encoding methylenetetrahydrofolate reductase (MTHFR) have been studied widely in various cancers, excluding thyroid cancer. However, reports on the association of various polymorphisms with certain cancers are contradictory.

MATERIALS AND METHODS

We have investigated whether the prevalence of the most common polymorphism (C677T) in the MTHFR gene has any link with various cancers, using genomic DNA and polymerase chain reaction restriction fragment length polymorphism (PCRRFLP) analysis.

RESULTS

The frequency of the heterozygous variant (677CT) but not that of 677TT was found to be significantly higher in colorectal cancer cases than in controls (p < 0.039; odds ratio 2.35 and 95% confidence interval 1.02-5.415). The frequencies for 677CT were 11.0 and 5.0% in colorectal cancer samples and controls, respectively. In ovarian cancer, the frequency of the 677TT variant was 6.0% which differed significantly (p < 0.026) from the control value of 1.0%. However, the frequencies of the variants in cervical, thyroid, and breast cancer cases did not differ from controls.

CONCLUSIONS

Our data taken together with other reports indicates that the polymorphism C677T of MTHFR is a risk factor for developing colorectal cancer but not cervical, thyroid, and breast cancers. The present study also reconfirms that frequencies of the variants are not gender-specific.

Central retinal vein occlusion in a young Chinese population: risk factors and associated morbidity and mortality

PURPOSE

The purpose of this study was to assess the risk factors for central retinal vein occlusion and associated morbidity and mortality in a Chinese population.

METHODS

The participants included patients with central retinal vein occlusion 40 years old and younger. Predisposing factors, mortality, and systemic complications were examined in this group.

RESULTS

Unilateral (n = 19) and bilateral (n = 3) central retinal vein occlusions were identified in a total of 22 patients (25 eyes), with a mean follow-up time of 37 months. Hypercholesterolemia (65%), hypertriglyceridemia (64%), and hyperhomocysteinemia (42%) were all identified as risk factors. Three patients (14%) developed stroke and 1 (5%) developed transient ischemic attacks during follow-up. Renal failure and pulmonary hypertension resulted in the death of two patients. The mean initial and final visual acuities (+ or - standard deviation) were 20/400 (+ or - 20/250) and 20/500 (+ or - 20/320), respectively, and treatments did not result in vision improvement (P = 0.57). The poor visual prognosis was likely due to macular edema in 7 eyes (28%), optic atrophy in 4 eyes (16%), and secondary glaucoma in 3 eyes (12%).

CONCLUSION

Morbidity and mortality are high in young Chinese patients with central retinal vein occlusion who may have associated serious complications including stroke, blindness, and death. Central retinal vein occlusion may serve as an initial clinical presentation of serious systemic diseases.

Homocysteine, methylenetetrahydrofolate reductase C677T polymorphism, and risk of retinal vein occlusion: a meta-analysis

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 micromol/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 (P<0.001, I(2) = 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 = 0.004, I(2) = 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.