Methylenetetrahydrofolate reductase C677T gene polymorphism in Turkish patients with polycystic ovary syndrome

Folate and Vitamin B12 Levels in Chilean Women with PCOS and Their Association with Metabolic Outcomes

Polycystic ovary syndrome (PCOS) is a common endocrine disorder that affects women of reproductive age. Many women with PCOS have been found to have an unbalanced diet and deficiencies in essential nutrients. This study aimed to assess the levels of folate and vitamin B12 (B12) and their relationship with metabolic factors in women with PCOS. Anthropometric, clinical, and genetic analyses were conducted to evaluate markers related to one-carbon metabolism in women with PCOS and in a control group. The PCOS group had a higher BMI and HOMA-IR (1.7 vs. 3.1; p < 0.0001). HDL cholesterol levels were 23% lower and triglyceride levels were 74% higher in women with PCOS. Although there were no significant differences in folate and B12 levels between the PCOS and control groups, over 60% of women with PCOS had low B12 levels (<300 pg/mL) and high homocysteine levels. In addition, the MTHFR A1298C and C677T polymorphisms were not associated with PCOS. Moreover, erythrocyte folate levels were positively correlated with fasting glucose, triglycerides, and free androgen index, and negatively correlated with SHBG and LH levels. These results suggest that B vitamins may be associated with the metabolic phenotype in PCOS. This study emphasizes the potential link between folate, vitamin B12, and metabolic and hormonal outcomes in women with PCOS.

Potential environmental toxicant exposure, metabolizing gene variants and risk of PCOS-A systematic review

Exposure of environmental toxicants such as potentially toxic metals and pesticides have largely been attributed to produce adverse effects on general women's health and to be more precise on the reproductive system. In order to explore exposure of toxicants and metabolizing gene variants as risk factor for polycystic ovarian syndrome (PCOS), literature search was carried out using the databases PubMed, Central Cochrane Library, Google Scholar, Science Direct with appropriate keywords upto 6 December 2020. While most of the studies indicate higher serum Cu concentration and lower concentration of Mn as risk factor, studies also report presence of higher pesticide concentration in PCOS women. Genes such as MTHFR, CYPs participate in the metabolism of toxicants and may show different response due to underlying genetic variants. Thus, toxicant exposure are to some extent responsible for the pathogenesis of syndrome through oxidative stress and endocrine disruption, but the susceptibility may vary due to the underlying genetic polymorphism of the exposed population.

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.

Genetic polymorphisms associated with polycystic ovary syndrome among Iranian women

Polycystic ovary syndrome (PCOS) involves abnormalities in ovarian, reproductive, and metabolic systems. Genetic polymorphisms associated with individual differences and variations might be related to complex disorders with unknown causes, including PCOS. Several leading genetic markers with known cellular functions have been identified among Iranian women presenting with PCOS. In particular, the existing evidence shows a significant relationship between PCOS and the following genetic polymorphisms: rs2275913 (interleukin-17A), rs9927163 (interleukin-32), Pro12Ala (peroxisome proliferator-activated receptor-γ), rs17173608 (chemerin), rs2236242 (vaspin), ApaI (vitamin D receptor), and rs7895833 (sirtuin 1). In addition, a higher risk of PCOS is associated with the rs2910164 (microRNA 146a), rs2241766 (adiponectin), -34 T/C (cytochrome 17), and rs1800682 (Fas) polymorphisms. Furthermore, protective effects against PCOS have been reported for the A4223C polymorphism of adenosine deaminase 1. Overall, the available data indicate that Iranian women with PCOS have a higher prevalence of polymorphisms in inflammation- and metabolism-related genes, but not in insulin-related genes. More extensive studies are needed to identify the ethnicity-related genetic associations in PCOS.

Significant association between methylenetetrahydrofolate reductase gene C677T polymorphism with polycystic ovary syndrome risk: A meta-analysis update

The methylenetetrahydrofolate reductase (MTHFR) may play a pathological role in polycystic ovary syndrome (PCOS). However, the conclusions of published reports on the relationship between the MTHFR C677T polymorphism and PCOS risk remain controversial.To derive a more precise estimation we performed a metaanalysis based on 22 studies that together included 2405 cases and 2419 controls. PubMed, EMBASE, WanFang and the Chinese National Knowledge Infrastructure databases were used to retrieve articles up to up to October 28, 2019. The crude odds ratios (ORs) with 95% confidence intervals (95% CI) were calculated to evaluate the association.Metaanalysis results showed a significant association between the MTHFR C677T polymorphism and PCOS risk in 3 genetic models (allele model: OR = 1.40, 95% CI = 1.27-1.53; dominant model: OR = 1.47, 95% CI = 1.17-1.85); homozygous model: OR = 1.90, 95% CI = 1.55-2.32). Moreover, significant associations were observed when stratified by ethnicity, source of controls, etiology, and genotype methods.This metaanalysis suggests that the T-allele of the MTHFR C677T polymorphism is associated with an increased risk of PCOS, especially in Asians further studies with larger population sizes are needed to confirm these results.

Can the genetic polymorphisms of the folate metabolism have an influence in the polycystic ovary syndrome?

OBJECTIVE

To investigate the association of the genetic variants of the folate metabolism genes (MTHFR C677T; MTHFR A1298C; MTR A2756G; MTRR A66G and RFC-1 A80G) with the development of polycystic ovary syndrome (PCOS).

SUBJECTS AND METHODS

This study included 203 women (99 women with PCOS and 104 controls). The genotyping was performed by PCR-RFLP. Chi-squared test and multiple logistic regression were used in the statistical analysis. Haplotype analysis was conducted using the SNPstat program. The results were presented in odds ratio (OR) and confidence interval of 95% (CI-95%), with a significance level of 5% (p ≤ 0.05).

RESULTS

The genotypic distribution of the RFC-1 A80G polymorphism showed significant difference between the two groups, showing that the heterozygous genotype (AG genotype) was most frequent in controls. The polymorphic homozygous (GG genotype) of MTRR A66G polymorphism were most frequent in controls. The T-C haplotype MTHFR C677T and A1298C polymorphisms were more frequent in the control group (OR = 0.19; CI 95% - 0.04 to 0.93 e p = 0.042). The multivariate analysis evidenced that family history of PCOS was more frequent in the PCOS group (OR = 3.29; CI 95% - 1.48 to 7.31; p = 0.003).

CONCLUSION

In our casuistry, the polymorphic homozygous of MTRR A66G polymorphism gene and heterozygous of RFC-1 A80G polymorphism gene, the haplotype T-C C677T and A1298C polymorphisms of MTHFR gene, can be associated with protective factors for the disease.

Potential genetic polymorphisms predicting polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a heterogenous endocrine disorder with typical symptoms of oligomenorrhoea, hyperandrogenism, hirsutism, obesity, insulin resistance and increased risk of type 2 diabetes mellitus. Extensive evidence indicates that PCOS is a genetic disease and numerous biochemical pathways have been linked with its pathogenesis. A number of genes from these pathways have been investigated, which include those involved with steroid hormone biosynthesis and metabolism, action of gonadotropin and gonadal hormones, folliculogenesis, obesity and energy regulation, insulin secretion and action and many others. In this review, we summarize the historical and recent findings in genetic polymorphisms of PCOS from the relevant publications and outline some genetic polymorphisms that are potentially associated with the risk of PCOS. This information could uncover candidate genes associating with PCOS, which will be valuable for the development of novel diagnostic and treatment platforms for PCOS patients.

Methylenetetrahydrofolate reductase C677T polymorphism and the risks of polycystic ovary syndrome: an updated meta-analysis of 14 studies

Some studies have reported an association between the Methylenetetrahydrofolate reductase (MTHFR) C667T genetic variant and risk of polycystic ovary syndrome (PCOS), although the results remain controversial. A systematic search was conducted on PubMed, Web of Science, EMBASE, Ovid, Chinese National Knowledge Databases and WanFang databases with relevant keywords. Fourteen studies of sixteen distinct populations involving 1478 PCOS cases and used to conduct a meta-analysis. The T allele was not significantly associated with increased risk of PCOS [OR: 1.08; 95% CI: 0.96–1.21]. In the stratified analysis by ethnicity, the T allele significantly increases risks for the Asian [OR = 1.31; 95% CI: 1.09–1.58] population. No significant associations were detected for the Middle Eastern population [OR = 1.26; 95% CI: 0.96–1.67] and the T allele was found to be protective in the Caucasian population [OR = 0.82; 95% CI: 0.68–0.99]. In conclusion, this meta-analysis suggests that MTHFR C667T variant can increase, decrease, or have no effect on the risks of PCOS depending on the ethnicity.

The Effect of Metformin Treatment on the Serum Levels of Homocysteine, Folic Acid, and Vitamin B12 in Patients with Polycystic Ovary Syndrome

Background and Objective:

Hyperhomocysteinemia is a well-known risk factor for cardiovascular disease. Although metformin therapy can increase homocysteine (Hcy) levels, it frequently is used as an oral medicine in women with polycystic ovary syndrome (PCOS), who might be at risk of catching diabetes mellitus. The aim of this study was to investigate the effect of metformin on the levels of serum Hcy, vitamin B12 (vit B12), and folic acid in patients with PCOS.

Materials and Methods:

An interventional study was designed with 18 patients with PCOS at the Fatemehzahra infertility Hospital in Babol, Iran. Metformin treatment (500 mg twice daily) was initiated in all patients for a period of consecutive 6 months. The levels of serum Hcy, vit B12, and folic acid were measured in the participants before and after metformin treatment.

Results:

The mean vit B12 level showed a significant decrease in patients after 6 months of metformin treatment (P = 0.002). However, there was no significant difference in serum folic acid levels. The mean Hcy levels increased after treatment, but this difference not was statistically significant. When patients were stratified into four subgroups by their insulin sensitivity and body mass index (BMI), relatively similar results were obtained in the subgroups, except that Hcy levels in the overweight/obesity group (BMI > 25 kg/m²) after treatment showed a significant increase (P = 0.01).

Conclusion:

These findings indicate that metformin increases the serum Hcy concentration in patients with PCOS especially in the women with BMI > 25 kg/m². The possible mechanism for this effect would be the obvious reduction in the levels of vit B12.

Association between High Serum Homocysteine Levels and Biochemical Characteristics in Women with Polycystic Ovarian Syndrome: A Systematic Review and Meta-Analysis

Background

Elevated homocysteine levels have been observed in previous studies of PCOS; however, the nature of the associations between high homocysteine levels and the biochemical characteristics of polycystic ovarian syndrome (PCOS)—such as obesity, insulin resistance (IR), and androgen levels—is still uncertain.

Methods

A systematic search was conducted electronically up to December 28, 2015 using specific eligibility criteria. Standardized mean difference (SMD) and the corresponding 95% confidence intervals (95% CIs) were used as a measure of effect size.

Results

A total of 34 studies (with 1,718 cases and 1,399 controls) of homocysteine levels in PCOS were pooled in this meta-analysis. Significantly lower homocysteine levels were found in controls than in PCOS patients (SMD = 0.895, 95% CI = 0.643–1.146, P<0.001; I² = 90.4% and P<0.001 for heterogeneity), regardless of the degree of obesity, IR, or androgen levels. Homocysteine levels in non-IR PCOS patients were significantly lower than those of PCOS patients with IR (SMD = 0.69, 95% CI = 0.37–1.01, P<0.01; I² = 0% and P = 0.50 for heterogeneity). However, metformin treatment did not appear to cause any significant change in the homocysteine levels of PCOS patients (SMD = –0.17, 95% CI = –1.10–0.75, P = 0.71; I² = 92% and P<0.01 for heterogeneity).

Conclusions

High homocysteine levels in women with PCOS are not related to degree of obesity, IR, or androgen levels. Metformin treatment cannot decrease the homocysteine levels in PCOS patients.

Is MTHFR 677 C>T Polymorphism Clinically Important in Polycystic Ovarian Syndrome (PCOS)? A Case-Control Study, Meta-Analysis and Trial Sequential Analysis

BACKGROUND

Optimum efficiency of the folate pathway is considered essential for adequate ovarian function. 677 C>T substitution in the 5, 10-methylene tertrahydrofolatereductase (MTHFR) gene compromises activity of the MTHFR enzyme by about 50%. The significance of correlation between 677C>T substitution and PCOS remains dubious due to the low power of published studies.

METHODS AND RESULTS

We analyzed MTHFR 677 C>T site in ethnically two different PCOS case-control groups (total 261 cases and 256 controls) from India. The data analysis revealed a lack of association between this polymorphism and PCOS [OR = 1.11 (95%CI = 0.71-1.72), P = 0.66]. Group-wise analysis on the basis of ethnicity also revealed no association in any of the ethnic groups [Indo-Europeans, P = 1; Dravidians, P = 0.70]. Homocysteine levels did not differ significantly between cases (15.51 μmol/L, SD = 2.89) and controls (15.89 μmol/L, SD = 2.23). We also undertook a meta-analysis on 960 cases and 1028 controls, which suggested a significant association of the substitution with PCOS in the dominant model of analysis (OR = 1.47 (95%CI = 1.04-2.09), P = 0.032]. Trial sequential analysis corroborated findings of the traditional meta-analysis. However, we found that the conclusions of meta-analysis were strongly influenced by studies that deviated from the Hardy Weinberg equilibrium. A careful investigation of each study and a trial sequential analysis suggested that 677 C>T substitution holds no clinical significance in PCOS in most of the populations.

CONCLUSION

In conclusion, MTHFR 677 C>T polymorphism does not affect PCOS risk in India. The association seen in the meta-analysis is due to an outlier study and studies showing deviation from the Hardy Weinberg equilibrium.

Circulating markers of oxidative stress and polycystic ovary syndrome (PCOS): a systematic review and meta-analysis

BACKGROUND Oxidative stress might be associated with polycystic ovary syndrome (PCOS), but relatively small studies published to date do not permit reaching a definitive conclusion. We aimed at conducting a systematic review and meta-analysis of studies evaluating circulating markers of oxidative stress in patients with PCOS. METHODS We conducted a systematic review of studies reporting circulating markers of oxidative stress in women with PCOS and controls published up to June 2012, using Entrez PubMed and EMBASE online facilities. Meta-analysis calculated standardized mean differences (SMDs) and 95% confidence intervals (95CI). RESULTS From 1633 potential studies identified electronically, 68 studies, including 4933 PCOS patients and 3671 controls, were selected. For each of nine circulating markers of oxidative stress, an individual meta-analysis was conducted. Compared with control women, patients with PCOS presented higher circulating concentrations of homocysteine (23% increase, SMD 0.6, 95CI, 0.4-0.8), malondialdehyde (47% increase, SMD 1.9, 95CI 1.2-2.6) and asymmetric dimethylarginine (36% increase, SMD 1.1, 95CI 0.6-1.6), and increased superoxide dismutase activity (34% increase, SMD 1.0, 95CI 0.5-1.4) and decreased glutathione levels (50% decrease, SMD -3.7, 95CI -6.2 to -1.2) and paraoxonase-1 activity (32% decrease, SMD -0.9, 95CI -1.3 to -0.4). Similar results were found when restricting the analyses to studies in which patients and controls were matched for age and body mass index. CONCLUSIONS Circulating markers of oxidative stress are abnormal in women with PCOS independent of weight excess. This finding suggests that oxidative stress may participate in the pathophysiology of this common disorder.

MTHFR C677T polymorphism is associated with hyperlipidemia in women with polycystic ovary syndrome

CONTEXT

Women with polycystic ovary syndrome (PCOS) are prone for coronary artery disease (CAD), and hyperhomocysteinemia is an independent risk factor for CAD. MTHFR deficiency is the most common cause of hyperhomocysteinemia, thereby provoking a possible association between PCOS and MTHFR C677T polymorphism.

AIMS

The aim of this study was to investigate an association of MTHFR C677T polymorphism with PCOS.

SETTINGS AND DESIGN

92 women with PCOS (Rotterdam criteria) and 95 age-matched controls were compared with respect to MTHFR C677T polymorphism. The 2 genotypes (CC and CT) obtained were compared with clinical and laboratory parameters in women with PCOS.

MATERIALS AND METHODS

In a case-control study, clinical, biochemical, hormonal and genetic analysis (PCR-RFLP of peripheral leucocytes) was carried out on all women with PCOS as well as controls.

STATISTICAL ANALYSIS

Student "t" test for quantitative and Chi-square test for nominal variables was used. For estimation of risk, odds ratio and 95% confidence interval were calculated.

RESULTS

The odds ratio of bearing a heterozygous genotype (CT) was 1.32 in women with PCOS as compared to controls (P = 0.48). No homozygous mutation (TT) was found in the study population. Serum cholesterol was more in heterozygous (CT) genotype (215.48 ± 25.56 mg/dl) as compared to normal (CC) genotype (203.29 ± 16.35 mg/dl) in women with PCOS (P = 0.01). Similarly, serum triglyceride was more in heterozygous (CT) genotype (95.86 ± 37.34 mg/dl) as compared to normal (CC) genotype (82.36 ± 20.88 mg/dl) in women with PCOS (P = 0.04).

CONCLUSIONS

Although not statistically significant, there is a slightly higher prevalence of heterozygous (CT) genotype in women with PCOS. MTHFR C677T polymorphism when present may confer an increased susceptibility to develop hyperlipidemia in women with PCOS. More prospective studies are needed to confirm whether this hyperlipidemia due to MTHFR C677T polymorphism clinically manifests into CAD in long term in women with PCOS.

Genetic factors that influence short-term neurodevelopmental outcome in term hypoxic-ischaemic encephalopathic neonates

It is difficult to predict outcome in neonates that experience perinatal hypoxic ischaemia. Morbidity and mortality may be affected by genetic factors that augment inflammatory and coagulative responses. This prospective study analysed the effects of proinflammatory cytokine gene polymorphisms (tumour necrosis factor-α [TNFA] 308G>A and interleukin-6 [IL6] 174G>C) and prothrombotic factor gene mutations (prothrombin G20210A, factor V Leiden G1691A and methylenetetra hydrofolate reductase [MTHFR] C677T) on the early neurological prognosis in 40 term hypoxic ischaemic encephalopathic neonates. There were significant relationships for Sarnat and Sarnat staging with electroencephalographic findings, transfontanelle ultrasound (US) results, early neonatal outcome and neurological morbidity. Genetic mutations in the prothrombotic proteins, the TNFA 308G>A polymorphism and the cerebrospinal fluid levels of TNF-α protein were not related to clinical stage, electroencephalography, transfontanelle US or neurological status at discharge or at postnatal months 6 and 12. The IL6 174GC genotype demonstrated a protective role, being significantly correlated with normal electroencephalography, transfontanelle US and normal neurological findings at discharge. In conclusion, the IL6 174GC gene polymorphism seems to play a role in determining the risk and/or severity of perinatal cerebral injury.