Folate Deficiency and/or the Genetic Variant Mthfr677C >T Can Drive Hepatic Fibrosis or Steatosis in Mice, in a Sex-Specific Manner

SCOPE

Disturbances in one-carbon metabolism contribute to nonalcoholic fatty liver disease (NAFLD) which encompasses steatosis, steatohepatitis, fibrosis, and cirrhosis. The goal is to examine impact of folate deficiency and the Mthfr677C >T variant on NAFLD.

METHODS AND RESULTS

This study uses the new Mthfr677C >T mouse model for the human MTHFR677C >T variant. Mthfr677CC and Mthfr677TT mice were fed control diet (CD) or folate-deficient (FD) diets for 4 months. FD and Mthfr677TT alter choline/methyl metabolites in liver and/or plasma (decreased S-adenosylmethionine (SAM):S-adenosylhomocysteine (SAH) ratio, methyltetrahydrofolate, and betaine; increased homocysteine [Hcy]). FD, with contribution from Mthfr677TT, provokes fibrosis in males. Studies of normal livers reveal alterations in plasma markers and gene expression that suggest an underlying predisposition to fibrosis induced by FD and/or Mthfr677TT in males. These changes are absent or reverse in females, consistent with the sex disparity of fibrosis. Sex-based differences in methylation potential, betaine, sphingomyelin, and trimethylamine-N-oxide (TMAO) levels may prevent fibrogenesis in females. In contrast, Mthfr677TT alters choline metabolism, dysregulates expression of lipid metabolism genes, and promotes steatosis in females.

CONCLUSION

This study suggests that folate deficiency predisposes males to fibrosis, which is exacerbated by Mthfr677TT, whereas Mthfr677TT predisposes females to steatosis, and reveal novel contributory mechanisms for these NAFLD-related disorders.

Homozygous MTHFR C667T carriers ≤45 years old develop central retinal vein occlusion five years earlier than wild type

PURPOSE

To assess age at 1st central retinal vein occlusion (CRVO) in carriers ≤ 45 years old of the methylenetetrahydrofolate reductase (MTHFR) C667T genotype compared to heterozygous and wild type, and to identify predictors of age at CRVO.

METHODS

Retrospective cohort study consisting of 18 MTHFR TT, 23 MTHFR TC and 28 MTHFR CC participants; information regarding age, sex, age at CRVO, history of dyslipidaemia, hypertension, smoking and plasma HC measured by immunoassay were collected.

RESULTS

Age at CRVO was lower in MTHFR TT than MTHFR TC and CC (32 ± 6 vs 38 ± 5 vs 37 ± 6 years, respectively, p = 0.005); plasma HC was higher in MTHFR TT than in the other genotypes [14.4 (10.8, 19.6) vs 10.4 ((8.6,12.5) vs 8.5 ((7.5,9.8) μmol/l, p = 0.0002). Smoking (cigarettes/day) independently predicted age at CRVO (p = 0.039) and plasma HC (p = 0.005); smoking status (yes/no) predicted ischemic CRVO (p = 0.01) that was more common in the MTHFR TT group (p = 0.006).

CONCLUSIONS

Carriers of the MTHFR TT genotype ≤ 45 years old develop their 1st CRVO on average 5 years earlier than the MTHFR CC genotype; smoking contributes to the prematurity and severity of CRVO in MTHFR TT carriers.

Methylenetetrahydrofolate reductase polymorphic variants C677T and A1298C in rectal cancer in Slavic population: significance for cancer risk and response to chemoradiotherapy

Background: Methylenetetrahydrofolate reductase (MTHFR) single nucleotide polymorphisms (SNPs) have been suggested as risk, prognostic, and predictive factors for colorectal cancer in various populations, but have not been validated so far. The aim of this study was to examine the association of MTHFR C677T (rs1801133) and A1298C (rs1801131) single nucleotide polymorphisms with the risk of rectal cancer as well as the response to neoadjuvant chemoradiotherapy (nCRT) based on 5-Fluorouracil (5-FU)/leucovorin (LV) in the locally advanced setting. Patients and methods: This case-control study included 119 healthy controls and 97 patients with locally advanced rectal cancer (LARC). For MTHFR genotyping, restriction fragment length polymorphism analysis (PCR-RFLP) was employed. Results: In silico analysis highlighted that SNPs C677T and A1298T correlate with MTHFR gene expression, and that gene expression profile correlates with cancer risk and stage. Using dominant and recessive models, it was found that the MTHFR 677CC vs. 677CT+677TT have increased risk of cancer development (odds ratio (OR): 2.27; 95% confidence interval (CI): 1.30-3.95, p = 0.002) as well as 677CC+677CT compared to 677TT (OR: 4.18, 95% CI: 1.16-14.99, p = 0.014). MTHFR 1298AA also shown increased risk for cancer development compared to 1298AC+1298CC (OR:2.0, 95% CI: 1.20-3.59, p = 0.035) Statistical analysis of combined genotypes highlighted the protective role of CT/AC combined genotype (OR: 3.15 95% CI: 1.576-6.279, p = 0.002) while the CC/AA genotype showed an increased risk for rectal cancer development (OR: 2.499, 95% CI: 1.246-5.081, p = 0.016) The carriers of the 677C/1298A haplotype had the highest risk for developing rectal cancer (OR: 1.74; 95% CI: 1.198-2.530, p = 0.002) while the 677T/1298C haplotype seems to provide a protective effect. (OR: 0.44; 95%CI 0.248-0.795, p = 0.003). No significant association with response to chemoradiotherapy was found. Conclusion: Our data point to MTHFR 667C allele and 1298A alleles as low-penetrance risk factors for rectal cancer in our population. To the best of our knowledge, this is the first study of this type performed on the Slavic population in the Western Balkan, as various population-based factors might also be significant our findings can be used for future meta-analyses and the construction of genetic cancer risk prediction panels.

Association between MTHFR C677T Gene Polymorphisms and the Efficacy of Vitamin Therapy in lowering Homocysteine Levels among Stroke Patients with Hyperhomocysteinemia

BACKGROUND

The impact of the methylenetetrahydrofolate reductase (MTHFR) C677T mutation on the relationship between plasma homocysteine (Hcy) levels and stroke has been extensively studied and documented in previous study. However, it remains unclear whether the MTHFR C677T mutation can affect the response to Hcy lowering treatment in stroke patients with hyperhomocysteinemia (HHcy). Understanding the impact of genetic factors on treatment response can help optimize personalized treatment strategies for stroke patients with HHcy. We aimed to investigate the potential association between the MTHFR C677T gene polymorphisms and the effectiveness of Hcy lowering treatment using vitamin therapy in stroke patients with HHcy.

METHODS

The MTHFR C677T genotype polymorphisms were identified using polymerase chain reaction-restriction fragment length polymorphism, and the distribution of three genotypes in the MTHFR C677T gene locus was compared. The treatment effects of Hcy lowering agents were compared among patients with different genotypes.

RESULTS

Among the 320 stroke patients enrolled in the study, 258 (80.6%) were diagnosed with HHcy. Of these, 162 patients (Effective Group) responded well to the clinical Hcy lowering treatment, while 96 patients (Invalid Group) failed to achieve sufficient response even after taking combination supplements of folic acid, Vitamin B6, and methylcobalamin for one month. Significant differences were observed in terms of age (p < 0.001), hypertension (p = 0.034), dyslipidemia (p = 0.022), hyperuricemia (p = 0.013) and genotype distribution of MTHFR C677T gene polymorphism (p < 0.001) between the Invalid group and the Effective group. The multivariate regression analysis revealed that the T allele (odd rations [OR], 1.327; 95% confidence interval [CI], 1.114-1.580; p = 0.0015) was independently associated with an insufficient Hcy lowering treatment effect. Additionally, the TT genotype was independently associated with insufficient response in both the codominant model (OR, 1.645; 95% CI, 1.093-2.476; p = 0.017) and the recessive model (TT versus CC + CT; OR, 1.529; 95% CI, 1.145-2.042; p = 0.004). However, no relationship was observed between CT + TT genotypes and poor treatment effect in the dominate model.

CONCLUSIONS

Our findings suggested that the TT genotype and T allele of MTHFR C677T polymorphism were independently associated with an insufficient Hcy lowering treatment effect in stroke patients with HHcy.

Relationship between MTHFR gene polymorphism and risk of thrombosis in postoperative patients with colorectal cancer

An association between the methylenetetrahydrofolate reductase (MTHFR) C667T genotype and the risk of colorectal cancer, as well as a link between MTHFR gene polymorphism and thrombosis, have been revealed. However, the connection between MTHFR gene polymorphism and the risk of thrombosis in patients with colorectal cancer has remained to be fully elucidated. The present study investigated the link between MTHFR gene polymorphism and basic clinical data, postoperative D-dimer (DDi), postoperative thromboelastogram and postoperative thrombosis in 591 patients who underwent surgery for colorectal cancer. Postoperative DDi, thromboelastogram and postoperative thrombosis were not significantly different among patients with colorectal cancer and different MTHFR genotypes. While the results were 'negative', the present study may help physicians understand that it is not necessary to detect MTHFR polymorphism for therapeutic purposes. Regarding the danger of venous thrombosis, more focus should be placed on the standardized procedural enforcement system for deep vein thrombosis prevention for patients undergoing pelvic and abdominal surgery.

Thymidylate Synthase (TYMS) and Methylenetetrahydrofolate Reductase (MTHFR) Gene Polymorphisms Associated With Severe Capecitabine Toxicity: The First Case From Saudi Arabia

Dihydropyrimidine dehydrogenase (DPD) is the major enzyme in the catabolism of fluoropyrimidine chemotherapy. Deficiencies in this enzyme level typically predispose patients to fluoropyrimidine toxicities, and they are often linked to DPYD gene polymorphisms. Other gene polymorphisms such as thymidylate synthase (TYMS) and methylenetetrahydrofolate reductase (MTHFR) may induce similar toxicities. We report a patient with resected stage III colon cancer presenting with severe toxicity to adjuvant capecitabine, a prodrug of 5-fluorouracil (5-FU). Her DPYD gene sequencing was normal. However, the patient was heterozygous for c.1298A>C (p.E429A) in the methylenetetrahydrofolate reductase (MTHFR) gene and c.*450_*455del in the thymidylate synthase (TYMS) gene. The capecitabine dose was reduced in subsequent treatments and then titrated up gradually with no major side effects reported.

Association between MTHFR gene C677T polymorphism and gestational diabetes mellitus in Chinese population: a meta-analysis

Background and purpose

The relationship of the methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism with the incidence of gestational diabetes mellitus (GDM) in the Chinese population remains controversial. This study aimed to further clarify the effect of the MTHFR gene C677T polymorphism on GDM risk among Chinese pregnant women based on current evidence.

Methods

Several databases were searched up to July 29, 2023 for relevant case-control studies. The numbers of patients with and without the T allele of the MTHFR gene C677T polymorphism in the GDM and control groups were determined, and all statistical analyses were performed by RevMan 5.3 software and STATA 15.0 software. Trial sequential analysis (TSA) was performed by TSA version 0.9 beta software to determine the required information size.

Results

A total of 17 case-control studies involving 12345 Chinese participants were included. The pooled results demonstrated that the T allele of the MTHFR gene C677T polymorphism was significantly associated with an increased risk of GDM, which was manifested by the five gene models of the MTHFR C677T polymorphism [T vs. C: odds ratio (OR)=1.59, P=0.03; TT vs. CC: OR=2.24, P<0.001; TC vs. CC: OR=1.28, P=0.05; (TT+TC) vs. CC: OR=1.55, P=0.003; TT vs. (TC+CC): OR=1.89, P<0.001]. Subgroup analysis based on the regions indicated that the significant relationship between the T allele of the MTHFR gene C677T polymorphism and an increased risk of GDM was detected only among the southern population [T vs. C: OR=1.62, P=0.09; TT vs. CC: OR=2.22, P=0.004; TC vs. CC: OR=1.17, P=0.28; (TT+TC) vs. CC: OR=1.43, P=0.03; TT vs. (TC+CC): OR=1.97, P=0.006]. TSA plots showed that the information sizes for the association between the MTHFR gene C677T polymorphism and GDM risk were sufficient in the homozygote (TT vs. CC) and recessive (TT vs. TC+CC) models.

Conclusion

The MTHFR gene C677T polymorphism is closely related to susceptibility to GDM in the southern Chinese population, and the C-T mutation serves as an important genetic risk factor for GDM. More well-designed large case-control studies are needed to further confirm the above findings.

Association between MTHFR c.677C>T variant and erectile dysfunction among males attending fertility clinic

ABSTRACT

Genetic risk factors have been shown to contribute to the development of sexual dysfunction. However, the role of methylenetetrahydrofolate reductase (MTHFR) gene variants in the risk of erectile dysfunction (ED) remains unclear. In this study, we recruited 1254 participants who underwent ED assessed by the International Index of Erectile Function-5. The MTHFR c.677C>T variant was also measured by fluorescence polymerase chain reaction (PCR). No significant difference in the genotypic frequency of the MTHFR C677T polymorphism (CC, CT, and TT) was observed between men from the ED and non-ED groups. In addition, on binary logistic regression analysis, both crude and adjusted models showed that the risk of ED was not significantly associated with the C677T polymorphism. Interestingly, a significantly higher frequency of the 677TT polymorphism was found in severe and moderate ED (P = 0.02). The positive correlation between the MTHFR 677TT polymorphism and severe ED was confirmed by logistic regression analysis, even after adjusting for potential confounders (odds ratio [OR] = 2.46, 95% confidence interval [CI]: 1.15-5.50, P = 0.02). These findings suggest a positive correlation between the MTHFR 677TT polymorphism and the risk of severe ED. Identification of MTHFR gene polymorphisms may provide complementary information for ED patients during routine clinical diagnosis.

Methylenetetrahydrofolate Reductase C677T (rs1801133) Polymorphism Is Associated with Bladder Cancer in Asian Population: Epigenetic Meta-Analysis as Precision Medicine Approach

The etiology of bladder cancer remains unclear. This study investigates the impact of gene polymorphisms, particularly methylenetetrahydrofolate reductase gene (MTHFR), on bladder cancer susceptibility, focusing on the rs1801133 single-nucleotide polymorphism (SNP). A meta-analysis was conducted after systematically reviewing the MTHFR gene literature, adhering to PRISMA guidelines and registering in PROSPERO (CRD42023423064). Seven studies were included, showing a significant association between the MTHFR C677T (rs1801133) polymorphism and bladder cancer susceptibility. Individuals with the T-allele or TT genotype had a higher likelihood of bladder cancer. In the Asian population, the overall analysis revealed an odds ratio (OR) of 1.15 (95% CI 1.03-1.30; p-value = 0.03) for T-allele versus C-allele and an OR of 1.34 (95% CI 1.04-1.72; p-value = 0.02) for TT genotype versus TC+CC genotype. The CC genotype, however, showed no significant association with bladder cancer. Notably, epigenetic findings displayed low sensitivity but high specificity, indicating reliable identified associations while potentially overlooking some epigenetic factors related to bladder cancer. In conclusion, the MTHFR T-allele and TT genotype were associated with increased bladder cancer risk in the Asian population. These insights into genetic factors influencing bladder cancer susceptibility could inform targeted prevention and treatment strategies. Further research is warranted to validate and expand these findings.

Association of Methylenetetrahydrofolate Reductase Gene Polymorphism in Mothers With Adverse Clinical Outcomes in Neonates

BACKGROUND

The presence of polymorphic methylenetetrahydrofolate reductase (MTHFR) in mothers poses a risk for numerous detrimental outcomes in neonates. The present study investigated the association of maternal MTHFR A1298C and C677T single nucleotide polymorphisms (SNPs) with the clinical outcomes in their neonates.

MATERIALS AND METHODS

The cross-sectional study included 60 mothers and their neonates. Blood samples from mothers were analyzed for MTHFR A1298C and C677T SNP genotyping by real-time polymerase chain reaction. Clinical details of mothers and neonates were documented. Study groups were stratified based on wild, heterozygous, and mutant genotypes for the respective polymorphisms observed in mothers. Multinomial regression was applied for the association, followed by gene model formulation to estimate the impact of the genetic variants on the outcomes.

RESULTS

The frequency percentages of mutant CC1298 and TT677 genotypes were 25% and 8.06%, respectively, and the mutant allele frequencies (MAF) were 42.5% and 22.5%. Percentages of adverse outcomes such as intrauterine growth restriction, sepsis, anomalies, and mortality were higher in neonates born to mothers with homozygous mutant genotypes. Maternal C677T MTHFR SNPs revealed a significant association with neonatal anomalies (p = 0.001). The multiplicative risk model depicted OR (95% CI) for CT vs. CC+TT as 3.0 (95% CI: 0.66-13.7), and for TT vs. CT+CC was 15 (95% CI: 2.01-112.12). The C677T SNP in mothers predicted a dominant model for neonatal death (OR (95% CI): 5.84 (0.57-60.03), p = 0.15), whereas the A1298C reported recessive model for 1298CC mothers (OR (95% CI): 11 (1.05-115.5), p = 0.02). Both the genotypes assumed a recessive model for adverse neonatal outcomes: OR (95%CI) for CC vs. AA+AC was 3.2 (0.79-12.9, p = 0.1), and for TT vs. CC+CT was 5.48 (0.57-175.7, p = 0.2). The risk for sepsis in neonates was nearly six times higher in those born from mothers with homozygous CC1298 and TT677 than in the wild and heterozygous variants.

CONCLUSION

Mothers with C677T and A1298C SNPs are highly susceptible to adverse outcomes in their neonates. Hence, screening the SNPs during the antenatal period can purposefully serve as a better predictive marker, following which proper clinical management could be planned.

Methylenetetrahydrofolate reductase polymorphisms and elevated plasma homocysteine levels in small vessel disease

INTRODUCTION

Despite its public health importance, the causes of small vessel disease (SVD) are not fully understood. The presence of SVD in monogenic twins indicates the involvement of genetic factors in the pathogenesis of this disease. The purpose of this study was to investigate the association of methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms with SVD risk.

METHODS

Patients with SVD and matched controls were recruited from Tianjin Union Medical Center and Tianjin Huanhu Hospital. Clinical and laboratory data were collected. Plasma total homocysteine (tHcy) and folate levels were measured, and MTHFR rs1801133 (C677T) and rs1801131 (A1298C) single-nucleotide polymorphisms were genotyped. We analyzed potential associations among SVD and MTHFR polymorphisms, tHcy, and folate levels.

RESULTS

Patients with SVD displayed significantly decreased plasma folate levels (Z = -3.537, p < .001) and increased tHcy levels (Z = 4.910, p < .001) compared with controls. Significantly different plasma tHcy levels were associated with rs1801133 (χ²  = 6.664, p = .036), and post hoc analysis indicated higher plasma tHcy levels in individuals carrying the TT allele compared with levels in those carrying the TC allele (Z = 2.478, p = .013). No significant differences in tHcy levels were observed for rs1801131 alleles. The genotype and allele frequencies of rs1801133 were different between SVD and control groups (χ²  = 9.378, p = .009). There was no significant difference in distributions of rs1801131 genotypes between the two groups, and multivariable logistic regression analysis showed that rs1801131 and rs1801133 were not significantly associated with the risk of SVD.

CONCLUSIONS

Our study indicates that an elevated plasma tHcy level is independently associated with the development of SVD. Although MTHFR rs1801133 is linked to increased plasma homocysteine (Hcy) levels, it is not a risk factor for SVD. rs1801131 is not related to Hcy levels or SVD risk.

5-Formyltetrahydrofolate promotes conformational remodeling in a methylenetetrahydrofolate reductase active site and inhibits its activity

The flavoprotein methylenetetrahydrofolate reductase (MTHFR) catalyzes the reduction of N5, N10-methylenetetrahydrofolate (CH₂-H₄folate) to N5-methyltetrahydrofolate (CH₃-H₄folate), committing a methyl group from the folate cycle to the methionine one. This committed step is the sum of multiple ping-pong electron transfers involving multiple substrates, intermediates, and products all sharing the same active site. Insight into folate substrate binding is needed to better understand this multifunctional active site. Here, we performed activity assays with Thermus thermophilus MTHFR (tMTHFR), which showed pH-dependent inhibition by the substrate analog, N5-formyltetrahydrofolate (CHO-H₄folate). Our crystal structure of a tMTHFR•CHO-H₄folate complex revealed a unique folate-binding mode; tMTHFR subtly rearranges its active site to form a distinct folate-binding environment. Formation of a novel binding pocket for the CHO-H₄folate p-aminobenzoic acid moiety directly affects how bent the folate ligand is and its accommodation in the active site. Comparative analysis of the available active (FAD- and folate-bound) MTHFR complex structures reveals that CHO-H₄folate is accommodated in the active site in a conformation that would not support hydride transfer, but rather in a conformation that potentially reports on a different step in the reaction mechanism after this committed step, such as CH₂-H₄folate ring-opening. This active site remodeling provides insights into the functional relevance of the differential folate-binding modes and their potential roles in the catalytic cycle. The conformational flexibility displayed by tMTHFR demonstrates how a shared active site can use a few amino acid residues in lieu of extra domains to accommodate chemically distinct moieties and functionalities.

Relationship between methylenetetrahydrofolate reductase gene polymorphisms and methotrexate drug metabolism and toxicity

BACKGROUND

Acute lymphoblastic leukemia (ALL) is the most common malignancy in children, and methotrexate (MTX) is the key drug for ALL. Studies on the relationship between High-Dose methotrexate (HD-MTX) toxicity and methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C genes have drawn different conclusions. This study aimed to investigate the relationship between the polymorphism of MTHFR C677T and A1298C genes and the toxicity responses of MTX.

METHODS

The MTHFR C677T and A1298C genotypes of 271 children with ALL who received HD-MTX chemotherapy in southern China from September 2017 to June 2021 were analyzed, and the toxicity of HD-MTX was evaluated and analyzed according to Common Terminology Criteria for Adverse Events (CTCAE) 5.0.

RESULTS

The MTHFR C677T and A1298C gene polymorphisms were not correlated with the 48-hour MTX blood concentrations (P>0.05). Unconditional logistic regression model analysis also revealed that the risk of liver function impairment [odds ratio (OR) =1.656, 95% confidence interval (CI): 1.179-2.324, P<0.05] and mucosal damage (OR =1.508, 95% CI: 1.042-2.183, P<0.05) were 1.656 and 1.508 times higher for the heterozygous mutant (CT), and homozygous mutant (TT) mutant type than for the wild-type (CC), wild-type, respectively. The risk of neutropenia and liver function impairment were 0.498 (OR =0.498, 95% CI: 0.251-0.989, P<0.05) and 6.067 (OR =6.067, 95% CI: 1.183-31.102, P<0.05) times higher in low-risk children with CT+TT mutant genotypes than in those with CC wild genotypes, respectively. Furthermore, the risk of mucosal damage was 1.906 times higher in high-risk children with the CT+TT genotype than in those with the CC genotype (OR =1.906, 95% CI: 1.033-3.518, P<0.05). The MTHFR A1298C genotypes differed in the incidence of liver function damage and gastrointestinal toxic reactions in children with ALL. Nonetheless, no increased risk of liver function impairment nor gastrointestinal reactions in children with the heterozygous mutant (AC)+CC mutation was observed.

CONCLUSIONS

Advancements in MTHFR genotype testing in children with ALL and the introduction of personalised treatments based on genotype results during HD-MTX chemotherapy will help to predict, prevent, and reduce the occurrence of adverse MTX-related toxic reactions.

New Genetically Determined Markers of the Functional State of the Cardiovascular System

Nowadays, cardiovascular diseases (CVDs) occupy a leading position in population mortality. Since it is known that the development of cardiovascular pathologies is determined mainly by the human genetic burden, an urgent task of primary prevention of CVDs is to assess the contribution of gene polymorphism to the formation of cardiovascular risk. The material for the study was the blood of volunteers aged 21 to 102 years. Polymorphisms were determined by real-time PCR. Multichannel volumetric sphygmography was performed to analyze the functional state of the vascular wall. The study revealed that the rs5742904 polymorphism of the ApoB gene was found to be absent in the studied groups of long-livers and descendants of long-livers. Results indicated that the carriage of the heterozygous variant of the MMP9 polymorphism is associated with a favorable prognosis for cardiovascular system functioning. A tendency towards an increase in the rate of biological age acceleration among subgroups with AA and GG genotypes of the MMP9 gene and a negative value of biological age acceleration among heterozygous carriers of this polymorphism allele were found. The conducted studies make it possible to identify new associations of the studied polymorphisms with the functional state of the cardiovascular system, which is of great clinical importance and requires further study.

Regional distribution of the MTHFR C677T polymorphism in Chinese females

Objective: For analyzing the distribution characteristics of MTHFR C677T polymorphism in Chinese females in order to provide information for reducing birth defects and formulating public health policies to prevent congenital malformations. Methods: Literature search in the last 6 years on "MTHFR C677T," "polymorphism" and "methylene tetrahydrofolate reductase." The included literature provides the MTHFR C677T frequency in healthy females in the corresponding regions. The data were grouped by the national administrative region as a unit to obtain the distribution information of the MTHFR C677T and alleles in the female population in every province, municipality or autonomous region. This was done for analyzing the overall distribution of the MTHFR C677T allele and the geographical distribution of pregnancy complications. Results: A total of 126 studies were included, covering five autonomous areas, four municipalities directly under the Central Government, as well as 22 provinces (except Taiwan Province) in China. MTHFR C677T polymorphism data of 27 groups of Chinese Han women and 31 groups of other Chinese females were obtained, and the chi-square test revealed notable inter-group differences (p = 0.000). The TT genotype and T allele of MTHFR C677T accounted for 18.2% (4.7%-38.3%) and 40.3% (19.7%-61.4%) of the Chinese female population, respectively, with a significant north-south difference. Chinese females had a consistent frequency of the T allele with the geographical distribution of pregnancy complications such as recurrent abortion and preeclampsia. Conclusion: With a obvious geographical gradient, the MTHFR C677T polymorphism distribution in Chinese females is consistent with the geographical distribution of multiple pregnancy complications, and the risk assessment for it might be included in primary prevention for birth defects.

Investigation of the Roles of MTHFR (C677T and A1298C) and MMP-2 (-1306C>T ) Variations in Bladder Cancer Development

OBJECTIVE

Bladder cancer is a complex malignancy and has been associated with high morbidity. Since susceptibility to bladder cancer development differs between individuals, determining the roles of MTHFR and MMP-2 gene variations associated with this cancer is important for analyzing differences in individual susceptibility. In this study, we aimed to investigate the role of MTHFR and MMP-2 gene variations in the development of bladder cancer in the Thrace region of Turkey.

MATERIALS AND METHODS

One hundred seventy-nine blood samples were collected, including 98 patients with bladder cancer and 81 healthy controls. DNA extraction was carried out with blood samples. Polymerase chain reaction-restriction fragment length polymorphism was applied to detect MTHFR C677T (rs 1801133), MTHFR A1298C (rs 1801131), and MMP-2 (-1306C>T) (rs 243865) gene variants.

RESULTS

For the MTHFR A1298C gene variation, CC genotype was the genetic risk factor (P=.0001), while AC genotype was the protective factor (P< .0001) in the development of bladder cancer. For the MMP-2 (-1306C>T) gene variation, TT genotype (P < .0001) and T allele (P=.0006) were genetic risk factors, while AC genotype (P=.0009) was the protective factor in the development of bladder cancer. For C677T/A1298C gene variations, CC-CC combined genotype was the genetic risk factor (P=.009), while CT-AC and CC-AC combined genotypes were potential protective biomarkers (P=.013 and P < .001, respectively).

CONCLUSION

In our study, TT genotype and T allele were determined as genetic risk factors for MMP-2 (-1306C>T) gene variation. For C677T/A1298C gene variations, CC- CC combined genotype was detected as the genetic risk factor in the development of bladder cancer.

A Potential Strategy for Atherosclerosis Prevention in Modernizing China - Hyperhomocysteinemia, MTHFR C677T Polymorphism and Air Pollution (PM2.5) on Atherogenesis in Chinese Adults

BACKGROUND

Atherosclerosis is one of the most important global health hazards and air pollution (AP, PM2.5) has been implicated. In addition to traditional risk factors hyperhomocysteinemia (HC) has been recognized in many parts of China related to risk of stroke.

METHODS

To evaluate the impact of HC (homocysteine >14μmol/l) and PM2.5 air pollution on atherogenesis in modernizing China, we studied 756 asymptomatic Chinese in China from 1998-2007. PM2.5 exposure, HC, folate, and methylenetetrahydrofolate reductase (MTHFR) C/T genotype were evaluated. Brachial flow-mediated dilation (FMD) and carotid intima-media thickness (IMT) were measured by ultrasound. Locations were categorized as zones 1, 2 and 3, with increasing PM2.5 exposure.

RESULTS

HC was higher (19.4±13.1 and 27.1±25.1μmol/l) in high PM2.5-polluted zones 2 and 3 than in zone 1 (9.7±4.5μmol/l, p<0.0015). The top HC tertile was characterized by lower folate and vitamin B12, but a higher proportion of the MTHFR TT genotype, Metabolic Syndrome (MS) and PM2.5 level (p=0.0018). FMD was significantly lower (7.3±2.3%) and carotid IMT thicker (0.63±0.12mm) in the top HC tertile, compared with low HC tertile (8.4±2.5%, p<0.0001; 0.57±0.1mm, p<0.0001 respectively). Similar differences in FMD and IMT were seen in zones 2 and 3, compared with zone 1 (p<0.0001). On multivariate regression, HC was related to male gender (beta=0.106, p=0.021), MTHFR-TT (beta=0.935, p<0.0001), locations (beta=0.230, p<0.0001) and folate-MTHFR interaction (beta=-0.566, p<0.0001). FMD was related to age (beta= -0.221; p<0.0001), male gender (beta= -0.194, p=0.001) PM2.5 and location (beta=-0.285 to -0.303, p<0.0001). Carotid IMT was related to PM2.5 (beta=0.173, p<0.0001), HC (0.122, p=0.006) but not to MTHFR or location, independent of age, gender, MS, and LDL-C. No significant HC-PM2.5 interaction effect on FMD and IMT was observed.

CONCLUSION

HC and PM2.5 pollution but not MTHFR genotype were both related to carotid IMT, independent of other traditional risk factors. This has potential implications in dietary and AP strategies for atherosclerosis prevention in China.

Association of MTHFR C667T Polymorphism, Homocysteine, and B Vitamins with Senile Cataract

Senile cataract has become the leading cause of visual impairment and even blindness in the world, but there are few reports on its relationship with methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms. This study is aimed to investigate the correlation between MTHFR gene polymorphisms or its enzyme metabolites and senile cataract. From January 2019 to June 2020, 663 patients with senile cataract at the Mianyang Central Hospital were enrolled as the observation group, and 646 healthy subjects were randomly selected as the control group. MTHFR gene polymorphisms (i.e., CC, CT, or TT genotypes) and serum homocysteine (HCY), folic acid (FOL), vitamin B12 (VitB12), and vitamin B6 (VitB6) levels were detected. The mutation rate of MTHFR C677T and HCY levels in the observation group were significantly higher than those in the control group, whereas FOL, VitB12, and VitB6 were significantly lower. With an increase in the MTHFR C677T mutation, HCY showed an upward trend, whereas FOL and VitB12 showed a decreasing trend in both the observation and control groups. Multiple logistic regression analysis showed that HCY and FOL were associated with senile cataract and MTHFR mutations; VitB12 was only associated with senile cataract. Compared to that with the CC genotype, CT and TT genotypes were associated with an increased senile cataract risk. Monitoring MTHFR gene polymorphisms and changes in serum HCY, FOL, and VitB12 levels could provide references in predicting senile cataract.

Methylenetetrahydrofolate Reductase C677T Gene Variant in Relation to Body Mass Index and Folate Concentration in a Polish Population

BACKGROUND

Methylenetetrahydrofolate reductase (MTHFR) is an enzyme responsible for producing an active form of folate. The MTHFR T677T genotype may have adverse health effects associated with weight gain and a reduction in folate availability.

AIM

In this study, we examined the influence of the MTHFR C677T variant on BMI and determined its role as a risk factor for obesity. We also assessed the relationships between the MTHFR C677T genotype and folate and vitamin B₁₂ concentrations in subjects before and after radical weight loss.

METHODS

The study group consisted of 1712 Caucasian adults of Polish nationality with a wide range of body mass indexes (BMIs). DNA was extracted from the blood, and the C677T variant was tested with RFLP-PCR and real-time-PCR.

RESULTS

There was no significant influence found for the MTHFR 677 TT genotype on BMI or the obesity risk in codominant, dominant or recessive inheritance models. Individuals with obesity and the TT genotype had significantly lower folate concentrations. After radical weight reduction, the impact of the risk genotype, as well as homeostasis between folate and vitamin B₁₂ in TT homozygotes, seems to be attenuated.

CONCLUSION

Although the MTHFR 677TT genotype is not directly related to a higher BMI in Polish adults, it has a detrimental effect on folate concentrations in individuals with high BMI values.

Relevance of Plasma Homocysteine and Methylenetetrahydrofolate Reductase 677TT Genotype in Sickle Cell Disease: A Systematic Review and Meta-Analysis

We evaluated the relevance of plasma homocysteine (HC) and the TT genotype of the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism (rs1801133) in sickle cell disease (SCD) and associated vaso-occlusive crisis (VOC) and ischemic stroke (IS). We identified in Embase and Medline 22 studies on plasma HC and 22 on MTHFR genotypes. Due to age-related HC differences, adult and paediatric SCD were separated: 879 adult SCD and 834 controls (CTR) yielded a neutral effect size; 427 paediatric SCD and 625 CTR favoured SCD (p = 0.001) with wide heterogeneity (I2 = 95.5%) and were sub-grouped by country: six studies (Dutch Antilles n = 1, USA n = 5) yielded a neutral effect size, four (India n = 1, Arab countries n = 3) favoured SCD (p < 0.0001). Moreover, 249 SCD in VOC and 419 out of VOC yielded a neutral effect size. The pooled prevalence of the MTHFR TT genotype in 267 SCD equalled that of 1199 CTR (4.26% vs. 2.86%, p = 0.45), and in 84 SCD with IS equalled that of 86 without IS (5.9% vs. 3.7%, p = 0.47); removal of one paediatric study yielded a significant effect size (p = 0.006). Plasma HC in paediatric SCD from Middle East and India was higher, possibly due to vitamin deficiencies. Despite its low prevalence in SCD, the MTHFR TT genotype relates to adult IS.

MTHFR Polymorphism and Folic Acid Supplementation Influence Serum Homocysteine Levels in Psoriatic Patients Treated with Methotrexate

Background: Hyperhomocysteinemia has been reported in psoriasis. We investigated the effect of methylenetetrahydrofolate reductase (MTHFR), polymorphism and folic acid supplementation on serum homocysteine levels in psoriasis. Methods: Serum homocysteine levels were detected at baseline and at week 12 in 201 patients who were genotyped with MTHFR rs1801133 without and 93 psoriatic patients with folate supplement. Results: TT genotype carriers of MTHFR rs1801133 had significantly higher serum homocysteine levels at baseline and at week 12, a better PASI 75 response rate at week 8, and a higher PASI 90 response rate at week 12 than the CT and CC genotype carriers. Multiple regression analysis demonstrated that serum homocysteine concentration at baseline was significantly associated with sex, weight, PASI score at baseline, and the rs1801133 genotype. The significant upregulation of serum homocysteine levels after treatment with methotrexate (MTX) was only observed in male CT and CC genotype carriers and female CC genotype carriers. In contrast, folic acid supplementation significantly decreased serum homocysteine levels after MTX treatment but only in male psoriatic patients. Conclusions: The effect of MTX on serum homocysteine levels was associated with the polymorphism of MTHFR rs1801133 and sex. Folic acid supplementation only decreased serum homocysteine levels in male psoriatic patients.

Association of MTHFR 677C>T polymorphism with pregnancy outcomes in IVF/ICSI-ET recipients with adequate synthetic folic acid supplementation

Methylenetetrahydrofolate reductase (MTHFR) genetic polymorphism rs1801133 (677C>T) will decrease the utilization of folate. Folate deficiency and its resulting homocysteine (HCY) accumulation can impair female fertility. Folic acid (FA) supplementation is necessary in pregnant women who are undergoing in-vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) - embryo transfer (ET), and especially in women with MTHFR rs1801133 C-to-T mutations. At present, affordable and accessible synthetic FA is mainly used. However, some studies have suggested that 5-methylenetetrahydrofolate (5-MTHF), a type of active FA, may be more suitable for women with the MTHFR 677C>T polymorphism, since it is safer and more effective. This retrospective study aimed to evaluate whether the MTHFR rs1801133 gene polymorphism is related to the pregnancy outcomes of IVF/ICSI-ET recipients after sufficient supplementation with FA instead of 5-MTHF. Data on 692 women undergoing IVF/ICSI-ET and taking adequate FA were collected. Participant characteristics were compared using the Kruskal-Wallis test and Pearson chi-square test. Logistic regressions were used to calculate the odds ratio (OR) and 95% confidence interval (95% CI), after adjusting for age, BMI, method of fertilization, method of embryo transfer and number of embryos transferred. An additive model (T/T vs. C/C), dominant model (C/T + T/T vs. C/C), and recessive model (T/T vs. C/T + C/C) were evaluated. Analysis revealed that MTHFR rs1801133 in IVF/ICSI-ET women with adequate FA supplementation was not associated with the pregnancy rate but with age (OR = 0.91, 95% CI = 0.88, 0.94, P < 0.001) and BMI (OR = 0.95, 95% CI = 0.90, 0.997, P = 0.037). In 349 clinically pregnant women, no association of the MTHFR 677C>T with pregnancy outcomes was found in the additive model, dominant model, or recessive model. Of the 273 women with positive pregnancy outcomes, 34 had a preterm delivery. MTHFR 677C>T was not associated with a preterm delivery after adjusting for age and BMI. The current results indicated that MTHFR polymorphism rs1801133 was not related to the pregnancy rate or pregnancy outcomes of women undergoing IVF/ICSI-ET with adequate synthetic FA supplementation, suggesting that simple supplementation with less expensive and readily available FA, rather than expensive 5-MTHF, appeared to be appropriate.

Association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and H-type hypertension: A systematic review and meta-analysis

PURPOSE

The polymorphism of methylenetetrahydrofolate reductase (MTHFR) gene C677T has been linked to H-type hypertension. But the conclusion remained controversial. To elucidate this issue, we performed a comprehensive meta-analysis to analyze the MTHFR C677T polymorphism and H-type hypertension.

MATERIALS AND METHODS

The English and Chinese databases were systematically searched to identify relevant studies until November 2020. RevMan 5.3 and Stata 12.0 software were used for meta-analysis. The odds ratio (ORs) and 95% confidence intervals (95% CIs) were used to assess the relationship between the MTHFR C677T polymorphism and H-type hypertension.

RESULTS

A total of 14 studies involving 1769 cases and 1443 controls were included. The meta-analysis results showed the association between MTHFR C677T polymorphism and H-type hypertension with the homozygous codominant model (OR = 3.30, 95% CI = 1.94-5.60), heterozygous codominant model (OR = 2.34, 95% CI = 1.53-3.58), dominant model (OR = 1.79, 95% CI = 1.33-2.41), recessive model (OR = 2.70, 95% CI = 1.73-4.21),and the allelic model (OR = 1.82, 95% CI = 1.41-2.35). All p-values were less than 0.05. Therefore, MTHFR C677T polymorphism has a positive correlation with the risk of H-type hypertension. Among them, TT mutation has the greatest impact on the activity of this enzyme, which causes Hcy to rise and leads to H-type hypertension.

CONCLUSION

In summary, our results provide sufficient data to support the hypothesis that the MTHFR C677T polymorphism is related to H-type hypertension susceptibility.

Sclerocarya birrea (Marula) Extract Inhibits Hepatic Steatosis in db/db Mice

Non-alcoholic fatty liver disease (NAFLD) is a spectrum of hepatic metabolic perturbations ranging from simple steatosis to steatohepatitis, cirrhosis and hepatocellular carcinoma. Currently, lifestyle modifications to reduce weight gain are considered the most effective means of preventing and treating the disease. The aim of the present study was to determine the therapeutic benefit of Sclerocarya birrea (Marula leaf extract, MLE) on hepatic steatosis. Obese db/db mice were randomly stratified into the obese control, metformin (MET) or MLE-treated groups. Mice were treated daily for 29 days, at which point all mice were euthanized and liver samples were collected. Hematoxylin and eosin staining was used for histological assessment of the liver sections, while qRT-PCR and Western blot were used to determine hepatic mRNA and protein expression, respectively. Thereafter, the association between methylenetetrahydrofolate reductase (Mthfr a key enzyme in one-carbon metabolism and DNA-methylation-induced regulation of gene transcription) and lipogenic genes was evaluated using Pearson's correlation coefficient. Mice treated with MLE presented with significantly lower body and liver weights as compared with the obese control and MET-treated mice (p ≤ 0.05). Further, MLE treatment significantly inhibited hepatic steatosis as compared with the obese control and MET-treated mice (p ≤ 0.05). The reduced lipid accumulation was associated with low expression of fatty acid synthase (Cpt1; p ≤ 0.05) and an upregulation of the fatty acid oxidation gene, carnitine palmitoyltransferase (Cpt1; p ≤ 0.01), as compared with the obese control mice. Interestingly, MLE treatment improved the correlation between Mthfr and Cpt1 mRNA expression (r = 0.72, p ≤ 0.01). Taken together, the results suggest that Marula leaf extracts may inhibit hepatic steatosis by influencing the association between Mthfr and genes involved in hepatic lipid metabolism. Further studies are warranted to assess DNA methylation changes in lipid metabolism genes.

Folic Acid Supplementation in Early Pregnancy, Homocysteine Concentration, and Risk of Gestational Diabetes Mellitus

We used a prospective cohort of pregnant women at 12 to 20 weeks gestation between 2002 and 2008 in Ottawa and Kingston to evaluate the impact of early pregnancy folic acid supplementation on the risk of gestational diabetes mellitus. Among 7552 eligible women, 84 (1.11%) were diagnosed of gestational diabetes mellitus. Non-significant associations were observed between gestational diabetes mellitus and folate supplementation, homocysteine levels, and methylenetetrahydrofolate reductase 677 TT genotype. Although we found no significant associations between folic acid supplementation and the risk of gestational diabetes mellitus, genetic associations were not confounded by lifestyle or socioeconomic factors, which may have biased previous studies.

Associations between Serum Betaine, Methyl-Metabolizing Genetic Polymorphisms and Risk of Incident Type 2 Diabetes: A Prospective Cohort Study in Community-Dwelling Chinese Adults

Previous studies have explored associations between betaine and diabetes, but few have considered the effects of genes on them. We aimed to examine associations between serum betaine, methyl-metabolizing genetic polymorphisms and the risk of type 2 diabetes in Chinese adults. This prospective study comprised 1565 subjects aged 40–75 without type 2 diabetes at baseline. Serum betaine was measured by high-performance liquid chromatography tandem mass spectrometry. Genotyping of methyl-metabolizing genes was detected by Illumina ASA-750K arrays. Cox proportional hazards model was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). During a median of 8.9 years of follow-up, 213 participants developed type 2 diabetes. Compared with participants in the lowest quartile of serum betaine, those in the highest quartile had lower risk of type 2 diabetes, adjusted HRs (95%CIs) was 0.46 (0.31, 0.69). For methylenetetrahydrofolate reductase (MTHFR) G1793A (rs2274976) and MTHFR A1298C (rs1801131), participants carrying 1793GA + AA and 1298AC + CC had lower risk of type 2 diabetes. Interactions of serum betaine and genotype of MTHFR G1793A and MTHFR A1298C could be found influencing type 2 diabetes risk. Our findings indicate that higher serum betaine, mutations of MTHFR G1793A and A1298C, as well as the joint effects of them, are associated with lower risk of type 2 diabetes.

Insufficient S-Sulfhydration of Methylenetetrahydrofolate Reductase Contributes to the Progress of Hyperhomocysteinemia

Aims: Hyperhomocysteinemia (HHcy) has been considered as a risk factor for cardiovascular disease, Alzheimer's disease, nonalcoholic fatty liver, and many other pathological conditions. Vitamin B6, Vitamin B12, and folate have been used to treat HHcy in clinics. However, at present, clinical therapies of HHcy display unsatisfactory effects. Here, we would like to explore a new mechanism involved in homocysteine (Hcy) metabolic disorders and a novel target for HHcy treatment. The key enzymes involved in Hcy metabolism deserve more insightful investigation. Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme regulating the intracellular Hcy metabolism. Until now, the effect of post-translational modification on the bioactivity of MTHFR still remains unclear. This study aimed at exploring the relationship between MTHFR S-sulfhydration and its bioactivity, and at identifying the contribution of an elevated Hcy level on MTHFR bioactivity. Results: By both in vivo and in vitro studies, we observed the following results: (i) The bioactivity of MTHFR was positively associated with its S-sulfhydration level; (ii) MTHFR was modified at Cys32, Cys130, Cys131, Cys193, and Cys306 by S-sulfhydration under physiological conditions; (iii) Hydrogen sulfide (H₂S) deficiency caused the decrease of MTHFR S-sulfhydration level and bioactivity in HHcy, which resulted in further aggravation of HHcy; and (iv) H₂S donors reversed the decreased bioactivity of MTHFR in HHcy, thus reducing the excessive Hcy level. Innovation and Conclusion: Our study suggested that H₂S could improve MTHFR bioactivity by S-sulfhydration, which might provide a candidate therapeutic strategy for HHcy. Antioxid. Redox Signal. 36, 1-14.

The Influence of MTHFR Polymorphism on Gray Matter Volume in Patients With Amnestic Mild Cognitive Impairment

The methylenetetrahydrofolate reductase (MTHFR) gene has been associated with Alzheimer's disease (AD) pathogenesis. Amnestic mild cognitive impairment (aMCI) represents a prodromal stage of dementia and involves a high risk of progression into AD. Although the effects of the apolipoprotein E (APOE) gene on structural alterations in aMCI have been widely investigated, the effects of MTHFR C677T and interaction effects of MTHFR × APOE genotypes on gray matter atrophy in aMCI remain largely unknown. In the present study, 60 aMCI patients and 30 healthy controls were enrolled, and voxel-based morphometry analysis was performed to inspect the effects of diagnosis, different genotypes, and their interactions on gray matter atrophy. The results showed that aMCI patients had significant gray matter atrophy involving the bilateral hippocampus, the right parahippocampal gyrus, and the left superior temporal gyrus compared with healthy controls. Besides, a substantial reduction in gray matter volume was observed in the right hippocampus region in APOE ε4 carriers from the aMCI group, compared with APOE ε4 non-carriers. A significant interaction was found between diagnosis and MTHFR C677T genotype on the right precuneus in healthy controls and aMCI patients not carrying APOE ε4 allele. Our findings may provide new evidence substantiating the genetic effects of MTHFR C677T on brain structural alternation in patients with aMCI.

Does personalised nutrition advice based on apolipoprotein E and methylenetetrahydrofolate reductase genotype affect dietary behaviour?

Background: Dietary intake is linked to numerous modifiable risk factors of cardiovascular disease. Current dietary recommendations in the UK to reduce the risk of cardiovascular disease are not being met. A genotype-based personalised approach to dietary recommendations may motivate individuals to make positive changes in their dietary behaviour. Aim: To determine the effect of a personalised nutrition intervention, based on apolipoprotein E (ApoE, rs7412; rs429358) and methylenetetrahydrofolate reductase (MTHFR, rs1801133) genotype, on reported dietary intake of saturated fat and folate in participants informed of a risk genotype compared to those informed of non-risk genotype. Methods: Baseline data (n = 99) were collected to determine genotype (non-risk vs risk), dietary intake and cardiovascular risk (Q-Risk®2 cardiovascular risk calculator). Participants were provided with personalised nutrition advice via email based on their ApoE and MTHFR genotype and reported intake of folate and saturated fat. After 10 days, dietary intake data were reported for a second time. Results: Personalised nutrition advice led to favourable dietary changes, irrespective of genotype, in participants who were not meeting dietary recommendations at baseline for saturated fat (p < 0.001) and folate (p = 0.002). Only participants who were informed of a risk ApoE genotype met saturated fat recommendations following personalised nutrition advice. Conclusion: Incorporation of genotype-based personalised nutrition advice in a diet behaviour intervention may elicit favourable changes in dietary behaviour in participants informed of a risk genotype. Participants informed of a non-risk genotype also respond to personalised nutrition advice favourably but to a lesser extent.

Associations of Homocysteine Metabolism With the Risk of Spinal Osteoarthritis Progression in Postmenopausal Women

CONTEXT

Although homocysteine accumulation is a reported risk factor for several age-related disorders, little is known about its relationship with osteoarthritis (OA).

OBJECTIVE

We investigated for associations of homocysteine and C677T polymorphism in methylenetetrahydrofolate reductase (MTHFR), which is involved in homocysteine clearance, with the development and progression of spinal OA through a combined cross-sectional and longitudinal cohort study.

METHODS

A total of 1306 Japanese postmenopausal outpatients participating in the Nagano Cohort Study were followed for a mean 9.7-year period. Cross-sectional multiple logistic regression for spinal OA prevalence at registration by serum homocysteine level was performed with adjustment for confounders. In addition to Kaplan-Meier analysis, multivariate Cox regression was employed to examine the independent risk of MTHFR C677T variant for spinal OA progression.

RESULTS

Multivariate regression analysis revealed a significant association between homocysteine and spinal OA prevalence (odds ratio 1.38; 95% CI 1.14-1.68). Kaplan-Meier curves showed a gene dosage effect of the T allele in MTHFR C677T polymorphism on the accelerated progression of spinal OA severity (P = 0.003). A statistically significant independent risk of the T allele for spinal OA advancement was validated by Cox regression analysis. Respective adjusted hazard ratios for the CT/TT and TT genotypes were 1.68 (95% CI, 1.16-2.42) and 1.67 (95% CI, 1.23-2.28).

CONCLUSION

Circulating homocysteine and C677T variant in MTHFR are associated with the prevalence rate and ensuing progression, respectively, of spinal OA. These factors may represent potential interventional targets to prevent OA development and improve clinical outcomes.

Portal Vein Thrombosis in a Patient With Methylenetetrahydrofolate Reductase Gene Mutation and Normal Homocysteine Levels

A 21-year-old male presented with chief complaints of abdominal pain, nausea, and vomiting and was found to have portal vein thrombosis (PVT) on computed tomography (CT) scan of the abdomen, which was redemonstrated on ultrasound. Thrombophilia workup was negative except that patient was heterozygous for methylenetetrahydrofolate reductase (MTHFR) gene mutation. Homocysteine levels were normal. The patient was started on enoxaparin and discharged on apixaban with the plan to continue anticoagulation for at least six months. Follow-up MRI after four months showed interval improvement of the main portal vein thrombus with the use of Eliquis.

A Heterodimeric Reduced-Ferredoxin-Dependent Methylenetetrahydrofolate Reductase from Syngas-Fermenting Clostridium ljungdahlii

The strict anaerobe Clostridium ljungdahlii can ferment CO or H2/CO2 via the Wood-Ljungdahl pathway to acetate, ethanol, and 2,3-butanediol. This ability has attracted considerable interest, since it can be used for syngas fermentation to produce biofuels and biochemicals. However, the key enzyme methylenetetrahydrofolate reductase (MTHFR) in the Wood-Ljungdahl pathway of the strain has not been characterized, and its physiological electron donor is unclear. In this study, we purified the enzyme 46-fold with a benzyl viologen reduction activity of 41.2 U/mg from C. ljungdahlii cells grown on CO. It is composed of two subunits, MetF (31.5 kDa) and MetV (23.5 kDa), and has an apparent molecular mass of 62.2 kDa. The brownish yellow protein contains 0.73 flavin mononucleotide (FMN) and 7.4 Fe, in agreement with the prediction that MetF binds one flavin and MetV binds two [4Fe4S] clusters. It cannot use NAD(P)H as its electron donor or catalyze an electron-bifurcating reaction in combination with ferredoxin as an electron acceptor. The reduced recombinant ferredoxin, flavodoxin, and thioredoxin of C. ljungdahlii can serve as electron donors with specific activities of 91.2, 22.1, and 7.4 U/mg, respectively. The apparent Km values for reduced ferredoxin and flavodoxin were around 1.46 μM and 0.73 μM, respectively. Subunit composition and phylogenetic analysis showed that the enzyme from C. ljungdahlii belongs to MetFV-type MTHFR, which is a heterodimer, and uses reduced ferredoxin as its electron donor. Based on these results, we discuss the energy metabolism of C. ljungdahlii when it grows on CO or H2 plus CO2. IMPORTANCE Syngas, a mixture of CO, CO2, and H2, is the main component of steel mill waste gas and also can be generated by the gasification of biomass and urban domestic waste. Its fermentation to biofuels and biocommodities has attracted attention due to the economic and environmental benefits of this process. Clostridium ljungdahlii is one of the superior acetogens used in the technology. However, the biochemical mechanism of its gas fermentation via the Wood-Ljungdahl pathway is not completely clear. In this study, the key enzyme, methylenetetrahydrofolate reductase (MTHFR), was characterized and found to be a non-electron-bifurcating heterodimer with reduced ferredoxin as its electron donor, representing another example of MetFV-type MTHFR. The findings will form the basis for a deeper understanding of the energy metabolism of syngas fermentation by C. ljungdahlii, which is valuable for developing metabolic engineering strains and efficient syngas fermentation technologies.

Associations of Genetic Variants of Methylenetetrahydrofolate Reductase and Serum Folate Levels with Metabolic Parameters in Patients with Schizophrenia

The one-carbon metabolism pathway is a suitable candidate for studying the genetic and epigenetic factors contributing to metabolic abnormalities in patients with schizophrenia. We recruited 232 patients with schizophrenia and analyzed their serum folate, vitamin B12, and homocysteine levels and metabolic parameters to investigate the associations of genetic variants of methylenetetrahydrofolate reductase (MTHFR) and folate levels with metabolic parameters. MTHFR C677T and MTHFR A1298C were genotyped. Results showed that MTHFR 677T allele carriers had lower levels of total cholesterol and low-density lipoprotein cholesterol than those with the 677CC genotype. Metabolic parameters did not differ between MTHFR 1298C and 1298AA carriers. Patients with a low folate level had a lower high-density lipoprotein cholesterol level than those with a normal folate level, but the effect disappeared after adjustment for age, sex, and types of antipsychotics used. We found significant interactions between MTHFR A1298C and the folate level status (low vs. normal) in terms of body mass index and waist circumference. In conclusion, genetic variants in one-carbon metabolism might play a role in antipsychotic-induced metabolic abnormalities. Prospective studies on drug-naïve, first-episode patients with schizophrenia are warranted to identify key regions of DNA methylation changes accounting for antipsychotic-induced metabolic abnormalities.

Associations between methylenetetrahydrofolate reductase polymorphisms and hepatocellular carcinoma risk: An update meta-analysis and trial sequential analysis

AIM

To evaluate the associations between the methylenetetrahydrofolate reductase (MTHFR) single-nucleotide polymorphisms (SNPs) and hepatocellular carcinoma (HCC) with meta-analysis and trial sequential analysis.

METHODS

PubMed, Embase, the Google Scholar, Wan fang database, VIP database, and China National Knowledge Infrastructure were extensively searched before April 2021. Odds ratios (ORs) and 95% confidence interval (95% CI) were calculated. Review Manager Version 5.3, STATA version 12.0 and TSA 0.9.5.10 Beta software were used.

RESULTS

Nineteen studies with 6941 HCC patients and 9436 controls were finally included. The MTHFR rs1801133 (C677T) SNP was associated with increased HCC risk under heterozygote genetic model (OR = 1.10, 95% CI = [1.01, 1.20]). For Subgroup analysis, increased risks of HCC were detected in Mongoloid, Chinese. For MTHFR rs1801131 (A1298C) SNP, increased risk of HCC was only observed in Caucasians (allelic: OR = 1.86, 95% CI = [1.49, 2.31]; homozygote: OR = 3.39, 95% CI = [2.18, 5.27]), interesting decreased risk was detected in Mongoloid (recessive: OR = 0.30, 95% CI = [0.15, 0.58]; homozygote: OR = 0.41, 95% CI = [0.24, 0.72]). Sensitivity analysis indicated stability in our results. Publication bias was not detected based on Begg test and Egger test. Trial sequential analysis indicated further studies to confirm the associations in MTHFR C677T polymorphism.

CONCLUSION

The MTHFR rs1801133 SNP was associated with an increased risk of HCC in Mongoloid population especially in Chinese. Increased HCC risk is also observed in Caucasian population for the MTHFR rs1801131 SNP, and decreased risk of HCC is remarkably discovered in Mongoloid and Chinese subgroups, which need further validation.

Recent Updates on Mechanisms of Resistance to 5-Fluorouracil and Reversal Strategies in Colon Cancer Treatment

5-Fluorouracil (5-FU) plus leucovorin (LV) remain as the mainstay standard adjuvant chemotherapy treatment for early stage colon cancer, and the preferred first-line option for metastatic colon cancer patients in combination with oxaliplatin in FOLFOX, or irinotecan in FOLFIRI regimens. Despite treatment success to a certain extent, the incidence of chemotherapy failure attributed to chemotherapy resistance is still reported in many patients. This resistance, which can be defined by tumor tolerance against chemotherapy, either intrinsic or acquired, is primarily driven by the dysregulation of various components in distinct pathways. In recent years, it has been established that the incidence of 5-FU resistance, akin to multidrug resistance, can be attributed to the alterations in drug transport, evasion of apoptosis, changes in the cell cycle and DNA-damage repair machinery, regulation of autophagy, epithelial-to-mesenchymal transition, cancer stem cell involvement, tumor microenvironment interactions, miRNA dysregulations, epigenetic alterations, as well as redox imbalances. Certain resistance mechanisms that are 5-FU-specific have also been ascertained to include the upregulation of thymidylate synthase, dihydropyrimidine dehydrogenase, methylenetetrahydrofolate reductase, and the downregulation of thymidine phosphorylase. Indeed, the successful modulation of these mechanisms have been the game plan of numerous studies that had employed small molecule inhibitors, plant-based small molecules, and non-coding RNA regulators to effectively reverse 5-FU resistance in colon cancer cells. It is hoped that these studies would provide fundamental knowledge to further our understanding prior developing novel drugs in the near future that would synergistically work with 5-FU to potentiate its antitumor effects and improve the patient's overall survival.

Shifting landscapes of human MTHFR missense-variant effects

Most rare clinical missense variants cannot currently be classified as pathogenic or benign. Deficiency in human 5,10-methylenetetrahydrofolate reductase (MTHFR), the most common inherited disorder of folate metabolism, is caused primarily by rare missense variants. Further complicating variant interpretation, variant impacts often depend on environment. An important example of this phenomenon is the MTHFR variant p.Ala222Val (c.665C>T), which is carried by half of all humans and has a phenotypic impact that depends on dietary folate. Here we describe the results of 98,336 variant functional-impact assays, covering nearly all possible MTHFR amino acid substitutions in four folinate environments, each in the presence and absence of p.Ala222Val. The resulting atlas of MTHFR variant effects reveals many complex dependencies on both folinate and p.Ala222Val. MTHFR atlas scores can distinguish pathogenic from benign variants and, among individuals with severe MTHFR deficiency, correlate with age of disease onset. Providing a powerful tool for understanding structure-function relationships, the atlas suggests a role for a disordered loop in retaining cofactor at the active site and identifies variants that enable escape of inhibition by S-adenosylmethionine. Thus, a model based on eight MTHFR variant effect maps illustrates how shifting landscapes of environment- and genetic-background-dependent missense variation can inform our clinical, structural, and functional understanding of MTHFR deficiency.

Methylenetetrahydrofolate Reductase Gene C677T Polymorphism-Dietary Pattern Interaction on Hyperhomocysteinemia in a Chinese Population: A Cross-Sectional Study

Background and aim: Hyperhomocysteinemia (Hhcy) has been recognized as a risk factor of several chronic diseases. There is accumulating evidence that both genetic and dietary factors had a notable impact on the risk of Hhcy. The present study aims to investigate the interaction effect on Hhcy between methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism and dietary intake.

Methods: Data were collected in a cross-sectional survey conducted in China; 3,966 participants with complete information on sociodemographic characteristics, anthropometric measurements, and dietary intake were included in the analyses. Dietary patterns were identified by factor analysis combined with cluster analysis. Blood samples were collected and MTHFR C677T genotypes were tested. Both the multiplicative statistical model and the additive model were conducted to investigate the interactive effects.

Results: Proportions of MTHFR C677T genotypes among participants were 29.2% for TT, 47.4% for CT, and 23.4% for CC. Three dietary patterns were identified, namely, the balanced pattern, the snack pattern, and the high-meat pattern. Compared with the balanced pattern, the other two patterns were associated with an elevated risk of Hhcy [the snack pattern: odds ratio (OR) 1.2, 95% confidence interval (CI) 1.0–1.5; the high-meat pattern: OR 1.3, 95% CI 1.1–1.6] after adjustment for age group, gender, residential region, and MTHFR C677T genotypes. A multiplicative interaction between the high-meat pattern and MTHFR 677TT genotype was observed, and synergistic effects between both the snack pattern and the high-meat pattern with MTHFR 677TT were identified.

Conclusion: Our results indicated that MTHFR C677T polymorphism and dietary patterns had interactive effects on Hhcy among the Chinese population. Subsequent targeted and appropriate dietary guidelines should be recommended for high-risk populations or patients of Hhcy carrying specific genotypes.

Hyperhomocysteinemia-related lung disease and hemolytic anemia with bone marrow features masquerading as myelodysplasia

Hyperhomocysteinemia is linked to TMA-related clinical symptoms such as apparent thromboembolism, microangiopathic hemolytic anemia (MAHA), and various types of end-organ damage due to microvascular thrombi; this is because high plasma levels of homocysteine impair the vascular endothelium. However, the association between hyperhomocysteinemia and pulmonary involvement is unclear. Here, we describe a 63-year-old male who was hospitalized with respiratory failure and MAHA with MDS-like features in the bone marrow. Plasma homocysteine levels were elevated significantly with 199.4 µmol/L (reference: 6.3-18.9) due to a homozygous (T/T) polymorphism for the 677C>T mutation within the MTHFR gene associated with chronic alcoholism-induced folate deficiency. Pulmonary lesions showed ground-glass opacity and there was pleural effusion. The patient was managed successfully with a combination of folate/mecobalamin supplementation, plasma exchange, and a methylprednisolone pulse, followed by oral prednisolone. Clinical symptoms, lung disease, MAHA, and bone marrow abnormalities improved as plasma homocysteine levels normalized.

MTHFR 677T-1298C haplotype in acute lymphoblastic leukemia: Impact on methotrexate therapy

INTRODUCTION

Functional variants of the Methylenetetrahydrofolate reductase (MTHFR) gene, the C677T and A1298C, have largely investigated in pharmacogenomics of Methotrexate (MTX) in acute lymphoblastic leukemia (ALL), yet the conclusions are inconsistent. In addition; most of these studies do not analyze haplotypes. Here, we investigate the MTHFR 677/1298 genotypes and the 677-1298 haplotype and characterize the MTX response in Northern African ALL patients.

METHODS

Genomic DNA was extracted from whole venous from a total of 28 patients with ALL. Genotyping were carried out with restriction fragment length polymorphism (RFLP). A toxicity score (TS) is calculated for each patient and correlate to the haplotype.

RESULTS

The allelic frequency of MTHFR 677T-1298C haplotype was 10.7% in ALL patients. According to the toxicity's score (TS) there was no significant differences between haplotype groups (p = 0.79): TS was higher with wild type of MTHFR (TS = 3.43; SEM ± 0.85) followed by combined genotype (677T-1298C) (TS = 2.67; SEM ± 0.88) and isolated variant (C677T or A1298C) (TS = 2.64; SEM ± 0.92).

CONCLUSION

Despite the limitation of this study; our results suggest that the MTHFR 677T-1298C haplotype is common in ALL and may be a promising HD-MTX chemotherapy-related adverse effects biomarker.

Effects of MTHFR C677T polymorphism on vitamin D, homocysteine and natural killer cell cytotoxicity in women with recurrent pregnancy losses

STUDY QUESTION

Is there any relationship between vitamin D [25 (OH) vitamin D], total plasma homocysteine and methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism in women with recurrent pregnancy losses (RPL)?

SUMMARY ANSWER

Women with MTHFR 677TT (homozygous mutation, TT) genotype have significantly lower vitamin D levels, higher homocysteine and natural killer (NK) cell cytotoxicities than those of women with MTHFR 677CC (wild type, CC) and 677CT (heterozygous mutation, CT) genotypes.

WHAT IS KNOWN ALREADY

Vitamin D insufficiency, MTHFR C677T polymorphism and hyperhomocysteinemia have been reported as risk factors for RPL. However, the relationship between these risk factors is not known in this population.

STUDY DESIGN, SIZE, DURATION

This is a retrospective cross-sectional study, including 837 women with RPL, who were enrolled in Reproductive Medicine and Immunology, Chicago Medical School, between 2012 and 2017.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women with two or more RPL prior to 20 weeks of gestation were included. To investigate whether the MTHFR C677T polymorphism affects the levels of homocysteine and vitamin D as well as immune parameters in women with RPL, biochemical data, such as plasma total homocysteine and serum vitamin D levels, and immune parameters, including NK cell cytotoxicity, were analyzed by MTHFR C677T genotype (CC, CT and TT).

MAIN RESULTS AND THE ROLE OF CHANCE

The serum level of vitamin D in TT was significantly lower when compared with those of CT (P = 0.001) and CC (P = 0.003), while the level of homocysteine in TT was significantly higher than those in CT (P = 0.01) and CC (P = 0.01). NK cytotoxicity in TT was significantly higher than that of CC (P = 0.04) but not CT (P = 0.09). There was a significant negative correlation between the levels of vitamin D and homocysteine in TT (r = -0.357, P < 0.01). In multivariate analysis, vitamin D insufficiency (<30 ng/ml) was an independent risk factor for hyperhomocysteinemia (adjusted odds ratio 1.89, 95% CI 1.41-2.52).

LIMITATIONS, REASONS FOR CAUTION

The study was retrospective and included only women with RPL but not healthy fertile controls. In addition, folic acid, vitamin B6 and B12 intake, which could modify the level of homocysteine and vitamin D, were not investigated. Thus, a considerable part of women might have folic acid and vitamin D supplementation and prenatal vitamin pills, and there are probable confounders in this study associated with unrestricted vitamin supplementation. Therefore, the findings should be carefully interpreted and applied to RPL women with MTHFR gene polymorphism.

WIDER IMPLICATIONS OF THE FINDINGS

The findings attained in this analysis regarding the MTHFR polymorphism and its relationship with vitamin D, homocysteine and NK cytotoxicity may aid in uncovering the underlying etiology and mechanism for RPL. The study highlights an interplay between nutrition and immune responses in RPL.

STUDY FUNDING/COMPETING INTEREST(S)

No external funding was received for this study. None of the authors have any conflict of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Evaluation of association between methylenetetrahydrofolate reductase and azoospermia: A meta-analysis

BACKGROUND

Infertility affects childbearing age couples all over the world. One of the important reasons for infertility is genetic factors. Our study evaluated the association between methylenetetrahydrofolate reductase (MTHFR) and azoospermia.

METHODS

Multiple databases like MEDLINE, EMBASE, Cochrane library, and China journal full-text database were used to search for relevant studies, and full-text articles involved in the evaluation of MTHFR and azoospermia. The results were evaluated using STATA 12.0. Heterogeneity analysis, sensitivity analysis, and bias analysis were also performed on the data.

RESULTS

Thirteen related studies eventually met the inclusion criteria. Significant association between C677T polymorphism and azoospermia (relative risk [RR] = 0.94 [0.90, 0.99], I2 = 60.9%, P = .002), and between A1298C polymorphism and azoospermia (RR = 0.98 [0.94, 1.02], I2 = 56.3%, P = .011) was observed. Meanwhile, in subgroup analysis, Caucasians had higher risk than Mongolians in association between MTHFR and azoospermia.

CONCLUSION

There was association between MTHFR polymorphism and azoospermia. Caucasian populations had higher risk than Mongolian populations in association between MTHFR and azoospermia.

Methylenetetrahydrofolate reductase gene polymorphisms in the risk of polycystic ovary syndrome and ovarian cancer

Polymorphisms of methylenetetrahydrofolate reductase (MTHFR) in hormone metabolism pathways might cause metabolic disturbances and contribute to the development of polycystic ovary syndrome (PCOS) and ovarian cancer, but the published studies were inconsistent. The aim of the present study was to evaluate the MTHFR C677T (rs1801133) and A1298C (rs1801131) gene polymorphisms in the risk of PCOS and ovarian cancer by meta-analysis. A comprehensive electronic search was conducted in databases for studies published from 1995 to 2020. The pooled ORs were calculated by Revman 5.2 software. Twenty-nine articles including 45 case–control studies were included. We found that MTHFR C677T polymorphisms were correlated with elevated PCOS risk (TT vs. CT+CC: OR = 1.41, 95%CI = 1.20–1.67; TT+CT vs. CC: OR = 1.54, 95%CI = 1.07–2.22; CT vs. CC+TT: OR = 1.18, 95%CI 1.04–1.33; TT vs. CC: OR = 1.47, 95%CI = 1.03–2.11; T vs. C: OR = 1.25, 95%CI = 1.06–1.47), which were more obvious in Middle Eastern subgroup. MTHFR A1298C polymorphisms were also associated with overall PCOS susceptibility (CC vs. AC+AA: OR = 2.55, 95% CI = 1.61–4.03; CC+AC vs. AA: OR = 1.84, 95%CI = 1.04–3.28; CC vs. AA: OR = 2.66, 95%CI = 1.68–4.22; C vs. A: OR = 1.67, 95%CI = 1.03–2.71), which were mainly reflected in Asian subjects. For ovarian cancer, MTHFR C677T polymorphisms were only related with elevated ovarian cancer risk in Asian population, while no significant association was found for A1298C polymorphisms. This meta-analysis suggested that MTHFR C677T and MTHFR A1298C polymorphisms were correlated with elevated PCOS risk. MTHFR C667T only posed a higher risk for ovarian cancer in Asians instead of other populations, while MTHFR A1298C polymorphisms were not related to ovarian cancer risk. Further studies are needed to validate the conclusion.

Relationship Between Gene Polymorphism of Methylenetetrahydrofolate Reductase C677T and Left Ventricular Hypertrophy in Chinese Patients with Chronic Kidney Disease

OBJECTIVE

This study aimed to investigate the relationship between the gene polymorphism of methylenetetrahydrofolate reductase (MTHFR) C677T and left ventricular hypertrophy (LVH) in patients with chronic kidney disease (CKD).

METHODS

A total of 763 Chinese patients with CKD undergoing genetic testing were included in the study. The association between the gene polymorphism of MTHFR C677T and echocardiographic parameters was analyzed through univariate and multivariate analyses.

RESULTS

We found a remarkably positive association between MTHFR C677T gene polymorphism and LVH indexes, including interventricular septal thickness (F = 3.8; P = .022), left ventricular posterior wall thickness (F = 3.0; P = .052), left ventricular mass (F = 3.9; P = .022), and left ventricular mass index (F = 2.6; P = .075). After adjusting for the potential confounders linking the polymorphism,we found that the positive association between the polymorphism and LVH indexes still existed in patients with CKD in some multiple linear regression models (P <.05).

CONCLUSION

MTHFR C677T gene polymorphism may be a genetic susceptibility marker for the development of LVH in patients with CKD.

Clinical Relevance of Methylenetetrahydrofolate Reductase Genetic Testing in Autism: A Case Report of Successful Clinical Outcome

Autism spectrum disorder is an emerging public health issue. The core features of autism spectrum disorder are persistent impairment in reciprocal social communication and interaction and restricted, repetitive patterns of behavior or interests. We now know that it encompasses disorders previously referred to as early infantile autism, childhood autism, Kanner autism, high-functioning autism, atypical autism, Asperger disorder, childhood disintegrative disorder, and pervasive developmental disorder not otherwise specified. While it is agreed that the etiology of autism spectrum disorder is largely unknown, certain environmental and genetic factors may be responsible for the disease. In particular, emerging evidence has suggested the role of C677T polymorphism in the methylenetetrahydrofolate reductase (MTHFR) gene as a possible risk factor. We present the case of a two-year-old boy with high risk for autism who was found on advanced investigation to have heterozygous polymorphism for MTHFR. This prompted us to add folic acid to his therapeutic regime. He was treated with high-dose folic acid along with conventional intervention, and went on to make excellent recovery. We conclude that pharmacological intervention has the potential to improve outcome in a subgroup of autistic children.

Single-nucleotide polymorphisms of methylenetetrahydrofolate reductase gene in a South Indian cohort with nonsyndromic cleft lip with or without palate

Objective:

Clefts of the lip, with or without cleft palate and cleft palate only, collectively called as orofacial clefts (OFCs) are one of the most common congenital malformations with varying degrees of penetrance and phenotype expressions. The aim of this study was to investigate the association between methylenetetrahydrofolate reductase (MTHFR) cytosine-to-thymine (c. 677 C>T), adenine-to-cytosine (c.1298 A>C) single- nucleotide polymorphisms (SNPs) and South Indian patients with the nonsyndromic cleft lip with or without palate (NSCL ± P).

Methods:

A cohort consisting of 25 cases of NSCL ± P and 18 controls from a South Indian cohort were included in this case–control study. Genetic analysis of c.677C>T and c.1298A C polymorphisms in the MTHFR gene was carried out using Sanger sequencing and analyzed from chromatogram profiles. Data interpretation was done using statistical software MedCalc Statistical Software version 16.2 and the Statistical Package for the Social Sciences (SPSS version 22.0).

Results:

DNA sequence analysis of the MTHFR gene revealed c. 677C>T and c. 1298A>C polymorphisms in 16% and 76% of NSCL ± P cases, respectively. Heterozygous variant in MTHFR c. 1298A>C polymorphism was found to be a significant risk factor (P = 0.0164) for NSCL ± P in South Indian ethnic population. c.677C>T polymorphism, in particular, was apparently dormant overall in the study population. These results offer certain novelty in terms of the distinctive pattern in SNPs of genotypes observed in the study.

Conclusion:

NSCL ± P is one of the most common and challenging congenital malformations with complex etiological basis. Common risk factors such as MTHFR SNPs, namely c.677C>T and c.1298A>C, are subjected to variations in terms of ethnic group, geographic region and micro/macro-environmental factors. Overall, our study has explored part of South Indian ethnic population and revealed a different and unique distribution of mutations in this sample population.

No Association Between ADIPOQ or MTHFR Polymorphisms and Gestational Diabetes Mellitus in South African Women

PURPOSE

Gestational diabetes mellitus (GDM) is a growing public health concern. GDM affects approximately 14% of pregnancies globally, and without effective treatment, is associated with short- and long-term complications in mother and child. Lower serum adiponectin (ADIPOQ) concentrations and aberrant DNA methylation have been reported during GDM. The aim of this study was to investigate the association between the ADIPOQ -11377C>G and -11391G>A, and methylenetetrahydrofolate reductase (MTHFR) 677C>T polymorphisms and GDM in a population of black South African women.

MATERIALS AND METHODS

DNA was isolated from the peripheral blood of 447 pregnant women with (n=116) or without (n=331) GDM, where after ADIPOQ (rs266729 and rs17300539) and MTHFR (rs1801133) polymorphisms were genotyped using TaqMan Quantitative Real-Time PCR analysis.

RESULTS

Women with GDM had a higher body mass index (p=0.012), were more insulin resistant (p<0.001) and had lower adiponectin levels (p=0.013) compared to pregnant women with normoglycemia. Genotypic, dominant and recessive genetic models showed no association between ADIPOQ rs266729 and rs17300539 and MTHFR rs1801133 polymorphisms and GDM. Intriguingly, the risk G allele of ADIPOQ rs266729 was associated with higher fasting glucose and insulin concentrations, while the T allele in MTHFR rs1801133 was associated with higher fasting insulin concentrations only.

CONCLUSION

ADIPOQ rs266729 and rs17300539 and MTHFR rs1801133 polymorphisms are not associated with GDM in a population of black South African women. These findings suggest that these single nucleotide polymorphisms (SNPs) do not individually increase GDM risk in the African population. However, the role of these SNPs in possible gene-gene or gene-environment interactions remain to be established.

Associations between MTHFR gene polymorphisms and the risk of intracranial hemorrhage: Evidence from a meta-analysis

INTRODUCTION

Previously, a number of genetic epidemiological studies have evaluated associations between MTHFR gene polymorphisms and the risk of intracranial hemorrhage (ICH), with controversial results. Accordingly, we carried out this meta-analysis to more conclusively evaluate associations between MTHFR gene polymorphisms and the risk of ICH.

METHODS

MEDLINE, EMBASE, Wanfang, VIP, and CNKI were searched comprehensively, and thirty-one genetic association studies were finally selected to be included in this meta-analysis.

RESULTS

Eight literatures (963 cases and 2,244 controls) assessed relationship between MTHFR rs1801131 (A1298C) polymorphism and the risk of ICH, and thirty-one literatures (3,679 cases and 9,067 controls) assessed relationship between MTHFR rs1801133 (C677T) polymorphism and the risk of ICH. We found that AA genotype of rs1801131 polymorphism was significantly associated with a decreased risk of intraventricular hemorrhage (IH) compared with AC/CC genotypes (OR = 0.63; p = .003), AC genotype was significantly associated with an increased risk of IH compared with AA/CC genotypes (OR = 1.55; p = .005), and A allele was significantly associated with a decreased risk of IH compared with C allele (OR = 0.75; p = .02). Additionally, CC genotype of rs1801133 polymorphism was significantly associated with a decreased risk of cerebral hemorrhage (CH) compared with CT/TT genotypes (OR = 0.75; p = .04), TT genotype was significantly associated with an increased risk of CH compared with CC/CT genotypes (OR = 1.27; p = .02), and C allele was significantly associated with a decreased risk of CH compared with T allele (OR = 0.85; p = .007).

CONCLUSIONS

This meta-analysis shows that rs1801131 polymorphism may influence the risk of IH, while rs1801133 polymorphism may influence the risk of CH.

Association of MTHFR C677T Polymorphism With Antipsychotic-Induced Change of Weight and Metabolism Index

Although antipsychotic medication contributed to the improvement of psychotic symptoms and reduced relapse, it induced weight gain and metabolic syndrome during antipsychotic medication treatment, which was seriously concerning. To investigate the association of methylenetetrahydrofolate reductase (MTHFR) gene C677T (rs1801133) polymorphism with antipsychotic-induced weight gain and metabolism parameter change, we employed 1,868 patients with schizophrenia in this study and randomly allocated them to seven antipsychotic medication treatment groups. All patients received antipsychotics monotherapy and were followed up for 6 weeks. Height, body weight, and metabolic parameters of the patients were measured at baseline and at 2, 4, and 6 weeks after antipsychotic treatment. We genotyped blood DNA from patients for MTHFR C677T polymorphisms and performed quantitative analyses using analysis of variance (ANOVA) and the analysis of covariance (ANCOVA) among three genotype groups. We found a predominant association between MTHFR C677T and body weight mass index (BMI) change after 6-week risperidone treatment. After 6-week treatment of risperidone, the BMI change rate (%) of MTHFR C677 carriers was significantly higher than that of MTHFR TT genotype carriers [CC (2.81 ± 6.77)%, CT (3.79 ± 5.22)%, TT (1.42 ± 3.53)%, F = 4.749, P = 0.009]. Some of the abnormal metabolic parameters were found to be associated with the MTHFR 677T, including higher levels of low-density lipoprotein and waist circumference. Validation was performed in an independent cohort, consisting of 252 patients with schizophrenia treated with three atypical antipsychotic drugs. Overall, the MTHFR C677 was associated with high risk of antipsychotic-induced weight gain and metabolism abnormalities.

Advances in Nutritional Epigenetics-A Fresh Perspective for an Old Idea. Lessons Learned, Limitations, and Future Directions

Nutritional epigenetics is a rapidly expanding field of research, and the natural modulation of the genome is a non-invasive, sustainable, and personalized alternative to gene-editing for chronic disease management. Genetic differences and epigenetic inflexibility resulting in abnormal gene expression, differential or aberrant methylation patterns account for the vast majority of diseases. The expanding understanding of biological evolution and the environmental influence on epigenetics and natural selection requires relearning of once thought to be well-understood concepts. This research explores the potential for natural modulation by the less understood epigenetic modifications such as ubiquitination, nitrosylation, glycosylation, phosphorylation, and serotonylation concluding that the under-appreciated acetylation and mitochondrial dependant downstream epigenetic post-translational modifications may be the pinnacle of the epigenomic hierarchy, essential for optimal health, including sustainable cellular energy production. With an emphasis on lessons learned, this conceptional exploration provides a fresh perspective on methylation, demonstrating how increases in environmental methane drive an evolutionary down regulation of endogenous methyl groups synthesis and demonstrates how epigenetic mechanisms are cell-specific, making supplementation with methyl cofactors throughout differentiation unpredictable. Interference with the epigenomic hierarchy may result in epigenetic inflexibility, symptom relief and disease concomitantly and may be responsible for the increased incidence of neurological disease such as autism spectrum disorder.

Methylenetetrahydrofolate reductase C677T and A1298C polymorphisms and male infertility risk: An updated meta-analysis

BACKGROUND

18 previous meta-analyses have been published on the methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms with male infertility risk. However, results of the previous meta-analyses were still inconsistent. Moreover, their meta-analyses did not assess false-positive report probabilities except one study. Furthermore, many new studies have been published, and therefore an updated meta-analysis and re-analysis of systematic previous meta-analyses were performed to further explore these issues.

OBJECTIVES

To determine the association between MTHFR C677T and A1298C polymorphisms and male infertility risk.

METHODS

Crude odds ratios and their 95% confidence intervals were used to assess the association between MTHFR C677T and A1298C polymorphisms and male infertility risk. We used the Bayesian false discovery probability (BFDP) to assess the credibility of statistically significant associations.

RESULTS

Fifty-nine studies were included concerning the MTHFR C677T and 28 studies were found on the MTHFR A1298C with male infertility risk. Overall, the MTHFR C677T was associated with increased male infertility risk in overall populations, Africans, East Asians, West Asians, South Asians, azoospermia, and Oligoasthenoteratozoospermia (OAT). In further sensitivity analysis and BFDP test, the positive results were only considered as "noteworthy" in the overall population (TT vs CC: BFDP = 0.294, CT + TT vs CC: BFDP = 0.300, T vs C: BFDP = 0.336), East Asians (TT vs CC: BFDP = 0.089, TT vs CT + CC: BFDP = 0.020, T vs C: BFDP < 0.001), West Asians (TT vs CC: BFDP = 0.584), hospital-based studies (TT vs CC: BFDP = 0.726, TT vs CT + CC: BFDP = 0.126), and OAT (TT vs CT + CC: BFDP = 0.494) for MTHFR C677T. In addition, a significantly increased male infertility risk was found in East Asians and population-based studies for MTHFR A1298C. However, we did not find that the positive results were considered as "noteworthy" in the overall and all subgroup analyses for MTHFR A1298C.

CONCLUSIONS

In summary, this study indicates that the MTHFR C677T is associated with increased male infertility risk in East Asians, West Asians, and OAT. No significant association was observed on the MTHFR A1298C with male infertility risk.