Methylenetetrahydrofolate (MTHFR), the One-Carbon Cycle, and Cardiovascular Risks

The 5-10-methylenetetrahydrofolate reductase (MTHFR) enzyme is vital for cellular homeostasis due to its key functions in the one-carbon cycle, which include methionine and folate metabolism and protein, DNA, and RNA synthesis. The enzyme is responsible for maintaining methionine and homocysteine (Hcy) balance to prevent cellular dysfunction. Polymorphisms in the MTHFR gene, especially C677T, have been associated with various diseases, including cardiovascular diseases (CVDs), cancer, inflammatory conditions, diabetes, and vascular disorders. The C677T MTHFR polymorphism is thought to be the most common cause of elevated Hcy levels, which is considered an independent risk factor for CVD. This polymorphism results in an amino acid change from alanine to valine, which prevents optimal functioning of the enzyme at temperatures above 37 °C. Many studies have been conducted to determine whether there is an association between the C677T polymorphism and increased risk for CVD. There is much evidence in favour of this association, while several studies have concluded that the polymorphism cannot be used to predict CVD development or progression. This review discusses current research regarding the C677T polymorphism and its relationship with CVD, inflammation, diabetes, and epigenetic regulation and compares the evidence provided for and against the association with CVD.

MTHFR Polymorphism Is Associated With Severe Methotrexate-Induced Toxicity in Osteosarcoma Treatment

BackgroundPrevious studies have revealed the critical role of methylene tetrahydrofolate reductase (MTHFR) polymorphisms in response to high-dose methotrexate (MTX)-induced toxicity in osteosarcoma patients. However, the conclusions remain controversial. In this setting, we performed a meta-analysis to determine their association more precisely.MethodEligible studies were searched and screened in PubMed, Web of Science, Cochrane Library, Clinical-Trials.gov, Embase, and China National Knowledge Infrastructure (CNKI) following specific inclusion and exclusion criteria. The required information was retrieved and collected for subsequent meta-analysis. Association between MTHFR polymorphism and MTX toxicity was evaluated by odds ratios (ORs).ResultsSeven studies containing 585 patients were enrolled and analyzed in this meta-analysis. Overall, the MTX related grade 3-4 liver toxicity was significantly associated with MTHFR rs1801133 allele (T vs. C: OR=1.61, 95%CI=1.07-2.42, P=0.024), homozygote (TT vs. CC: OR=2.11, 95%CI=1.06-4.21, P=0.011), and dominant genetic model (TT/TC vs. CC: OR=3.15, 95%CI=1.30-7.60, P=0.035) in Asian population. Meanwhile, close associations between MTX mediated grade 3-4 mucositis and MTHFR rs1801133 polymorphism were identified in allele contrast (T vs. C: OR=2.28, 95%CI=1.49-3.50, P<0.001), homozygote comparison (TT vs. CC: OR=4.07, 95%CI=1.76-9.38, P=0.001), heterozygote comparison (TC vs. CC: OR=2.55, 95%CI=1.20-5.42, P=0.015), recessive genetic model (TT vs. TC/CC: OR=2.09, 95%CI=1.19-3.67, P=0.010), and dominant genetic model (TT/TC vs. CC: OR=2.97, 95%CI=1.48-5.96, P=0.002). Additionally, kidney toxicity was corelated with the heterozygote comparison (TC vs. CC: OR=2.63, 95%CI=1.31-5.29, P=0.007) of rs1801133 polymorphism.ConclusionThe MTHFR rs1801133 polymorphism was significantly associated with severer liver toxicity induced by high-dose MTX treatment in the Asian population. In the meantime, patients with MTHFR rs1801133 polymorphism were predisposed to MTX- related mucositis.

A Retrospective Cross-Sectional Cohort Trial Assessing the Prevalence of MTHFR Polymorphisms and the Influence of Diet on Platinum Resistance in Ovarian Cancer Patients

Ovarian cancer has the lowest survival rate in gynaecologic malignancies with a 5-year survival rate of 43%. Platinum resistance is one of the main drivers of ovarian cancer mortality, of which aberrant methylation has been cited as a significant contributor. Understanding the essential role of the methylenetetrahydrofolate reductase enzyme (MTHFR) on DNA synthesis and repair, and how nutrient status can vastly affect its performance, led to the investigation of MTHFR status and dietary influence on platinum response in epithelial ovarian cancer (EOC) patients. Twenty-five adult female patients who completed first-line platinum-based chemotherapy for primary ovarian cancer were selected from Icon Cancer Centres in Australia. Participants were grouped based on platinum response. A full medical and family history, food frequency questionnaire and single blood test were completed, testing for MTHFR polymorphisms, serum folate, serum and active B12 and homocysteine levels. Nineteen of twenty-five participants had an MTHFR polymorphism. Of those, 20% were compound heterozygous, 12% were heterozygous C677T (CT), 4% homozygous C677T, 12% homozygous A1298C and 28% were heterozygous A1298C (AC). Statistically significant associations were found between dietary zinc (p = 0.0086; 0.0030; 0.0189) and B12 intakes in CT genotypes (p = 0.0157; 0.0030; 0.0068) indicating that zinc or vitamin B12 intakes below RDI were associated with this genotype. There were strong associations of vitamin B6 intakes in AC genotypes (p = 0.0597; 0.0547; 0.0610), and dietary folate in compound heterozygotes with sensitive and partially sensitive disease (p = 0.0627; 0.0510). There were also significant associations between serum folate (p = 0.0478) and dietary B12 (p = 0.0350) intakes above RDI and platinum sensitivity in wild-types as well as strong associations with homocysteine levels (p = 0.0886) and zinc intake (p = 0.0514). Associations with dietary B12 (p = 0.0514) and zinc intakes (p = 0.0731) were also strong in resistant wild types. Results indicate that dietary zinc, B12 and B6 intakes may be associated with platinum sensitivity dependent on MTHFR genotype. These results require further research to clarify the dosages necessary to elicit a response; however, they provide a novel foundation for acknowledging the role of diet on treatment response in EOC.

PREVALENCE OF MTHFR GENE 677C>T POLYMORPHISM IN THE PATIENTS WITH PSORIASIS VULGARIS

The study aimed to investigate the relationship between carriage of 677C>T polymorphism in the gene of methylene tetrahydrofolate reductase (MTHFR) and plaque psoriasis in patients in Bulgaria. We examined the prevalence of MTHFR C677T genotype in patients with psoriasis, as well as the relationship of the polymorphism with disease severity. Our study covered63 patients with psoriasis and 98psoriasis-free control subjects from northern Bulgaria. MTHFR677C>T genotype was verified by the PCR-RFLP method. There was no significant difference between carriage of TT genotype among the patients and controls: 12.7% versus 10.8 %in controls, OR 1.203, (CI 95% 0465-3.175), p>0.05 respectively. There was a higher PASI score in patients, carriers of TT genotype of MTHFR polymorphism 677C>T than in non-carriers, 28.18versus 24.87 respectively, but not significant. Conclusion: Carriage of TT genotype of MTHFR polymorphism 677C>T was not associated with Psoriasis Vulgaris in the northern Bulgarian population when compared to healthy controls.

A COMPARATIVE STUDY ON RISK OF OSTEOPOROSIS ASSOCIATED WITH THE USE OF VALPROATE VERSUS LEVETIRACETAM IN EPILEPTIC PATIENTS AND ITS RELATIONSHIP WITH METHYLENE TETRA-HYDRO FOLATE REDUCTASE GENOTYPES

Objective: The study objects at assessing and comparing the intensity of the effect of valproate (VPA) and levetiracetam (LV) on the bone mass in young adult epileptic patients while distinguishing their methylene tetra-hydro folate reductase (MTHFR) genotypes and correlating MTHFR polymorphism and antiepileptic drugs (AEDs) usage with the risk of development of osteoporosis. Methods: The study design was a comparative, prospective, and observational study. It was conducted at Princess Esra Hospital (PEH), Hyderabad and genotype testing was carried out at Salar-e-Millat Research lab (PEH). The consent was obtained from total 70 subjects, divided into three groups: Group 1: 18 patients receiving sodium VPA monotherapy Group 2: 17 patients receiving LV monotherapy Group 3: 35 healthy control subjects from general population. Patients of either gender within age group of 15–40 years, experiencing generalized tonic-clonic seizures or focal seizures, receiving the AED for duration of time ≥2 years were included in the study. Results: Our study showed significant correlation between the AEDs treatment and MTHFR polymorphism in predisposing osteoporosis. Conclusion: The variants of MTHFR gene (C677T) are prone to develop increased levels of homocysteine as a result of decreased activity of the enzyme in their bodies which are further increased in patients receiving AEDs. Monitoring of homocysteine levels in epileptic patients especially in the mutants of MTHFR gene along with their periodic testing of bone mineral density levels is recommended. Treatment for low folate and calcium levels is recommended in these patients to correct their deficiencies.

Association of MTHFR C677T and A1298C Polymorphisms with Susceptibility to Chronic Lymphocytic Leukemia: A Systematic Review and Meta-Analysis

Background: The relation between methylenetetrahydrofolate reductase)MTHFR( polymorphisms and the risk of developing Chronic lymphocytic leukemia (CLL) is not still clear, while there are reports about the association of MTHFR C677T and A1298C polymorphisms with developing CLL, there are other reports that rolled out the association of MTHFR polymorphisms with developing CLL. Therefore herein we carried out this meta-analysis to clear the association of MTHFR polymorphisms with the risk of CLL Methods: A comprehensive search was performed through PubMed, Scopus and Embase from inception to Aug 2020. Odds ratios (OR) with their corresponding 95% confidence intervals (CI) for five possible genetic models were calculated. Heterogeneity was evaluated using the Cochran Q test and the I2 statistic. Results: Totals of 1290 cases and 1887 controls for the C677T polymorphism and 1117 cases and 1256 controls for the A1298C polymorphism were included in our analysis. Analyzing the MTHFR C677T and A1298C polymorphisms genotypes showed an association between MTHFR polymorphism at A1298C under Allelic model and the risk of CLL (OR = 1.12, 95% CI = 1.01–1.25), however there was no association between MTHFR polymorphism at MTHFR C677T and risk of CLL. Conclusion: The risk of developing CLL might be associated with MTHFR polymorphism at A1298C under allelic model and not associated with MTHFR polymorphisms at C677T, However, further studies considering other factors such as age, gender, ethnicity, gene-gene interaction and environmental condition are needed to clear the true association of MTHFR polymorphisms with CLL.

Interplay among the Variants of One Carbon Metabolism, Methylenetetrahydrofolate Reductase Polymorphisms and Lung Cancer

Introduction: Folates perform an integral task in DNA synthesis, methylationand repair. Methylenetetrahydrofolate Reductase (MTHFR) potrays a key part in the metabolism of folate and regulates the equilibrium between the various forms of folate for DNA synthesis and DNA methylation. MTHFR irrevocably transforms 5,10 methylenetetrahydrofolate to 5-methyltetrahydrofolate, the principal circulating folate and the carbon donor for remethylation processes. MTHFR is vastly polymorphic in the general population. Materials and Methods: It was a case-control study conducted during March 2010 to September 2011 in the Department of Pulmonary Medicine in collaboration with the Department of Biochemistry at Government Medical College and Hospital, Chandigarh, to see whether any association exists between the variants of one carbon metabolism, MTHFR polymorphisms (C677T and A1298C), and lung cancer. Twenty biopsy proven lung cancer patients and 20 age and sex matched cancer-free controls were selected. Results: The mean serum folate in cases was higher (12.84 ng/mL±7.527 ng/mL) as compared to controls (4.46 ng/mL±1.346 ng/mL), suggesting that high levels of serum folate are associated with lung cancer. There was no significant variance in the levels of vitamin B12 and plasma homocysteine between cases and controls. No MTHFR polymorphism C677T was seen in the blood and the bronchial biopsy samples of all cases as well as blood samples of all the controls. The MTHFR polymorphism A1298C was present in the blood as well as bronchial biopsy samples of cases as well as blood of controls. Thus, in the present study, there was no relation of this polymorphism with lung cancer. Conclusion: Polymorphisms in MTHFR may contribute to lung cancer. More research on the basis of cellular and molecular mechanisms of lung cancer is urgently needed to aid in understanding of pathogenesis of the disease.

MTHFR Gene Polymorphisms and Cardiovascular Risk Factors, Clinical-Imagistic Features and Outcome in Cerebral Venous Sinus Thrombosis

Cerebral venous sinus thrombosis (CVST) as a severe neurological emergency, is represented by variable conditions in its clinic presentation, onset, risk factors, neuroimagistic features and outcome. The genetic polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene C677T and A1298C was associated with CVST. We aimed to characterize the prevalence of MTHFR gene polymorphisms associated with cardiovascular risk factors in the group of patients with CVST. Also, we studied additional causes associated with CVST including local infections, general infections, obstetric causes (pregnancy, puerperium) and head injury. This is a retrospective study including 114 patients which referred to our hospital between February 2012–February 2020. The protocol included demographic (age, sex), clinical, neuroimagistic features, paraclinic (genetic polymorphism of MTHFR, factor V G1691A—Leiden, prothrombin G20210A, PAI-1 675 4G/5G; Homocysteine level, the lipid profile, blood glucose and Glycohemoglobin HbA1c, high- sensitive C- reactive protein- hsCRP) data, as well as treatment and outcome. The mean age was 37.55 years with a female predominance (65.79%). In the first group of patients with inherited thrombophilia (60 cases; 52.63%) we found genetic mutation includes MTHFR C677T (38.59%) and A1298C (14.03%), factor V G1691A- Leiden (15.78%), prothrombin G20210A (2.63%), PAI-1 675 4G/5G (42.98%), and hyperhomocysteinemia (35.08%). At the second group with other etiology of CVST, except thrombophilia, we included 54 patients (47.36%). The most common sites of thrombosis were the superior sagittal sinus (52.63%). Headache was the most common symptom (91.22%) and seizures were the main clinical presentation (54.38%). The MTHFR polymorphism was significantly correlated with higher total cholesterol (TC) (p = 0.023), low- density lipoprotein cholesterol (LDL) (p = 0.008), homocysteine level (tHcy) (p < 0.001). Inside the first group with MTHFR polymorphism we have found a significant difference between the levels of homocysteine at the patients with MTHFR C677T versus MTHFR A1298C polymorphism (p < 0.001). The high-sensitive C-reactive protein (hsCRP) was increased in both groups of patients, but the level was much higher in the second group (p = 0.046). Mortality rate was of 2.63%. Demographic, clinical and neuroimagistic presentation of CVST in our study was similar with other studies on the matter, with a high frequency of thrombophilia causes. MTHFR gene polymorphisms (C677T and A1298C) are increased in prevalence in CVST. PAI-1 675 4G/5G gene mutation seems to be involved in CVST etiology. Plasma C-reactive protein level and hyperhomocysteinemia should be considered as a prognostic factor in CVST.