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.

Investigating the Association of MTHFR C677T Gene Polymorphism with Recurrent Spontaneous Abortion Among Azerbaijani Women from Northwest Iran

Background: Recurrent spontaneous abortion (RSA), defined as two or more succeeding abortions during 20 weeks of gestation, affects 3-5% of pregnancies. Several studies have found that most women with RSA had at least one (and sometimes two copies) of the methylenetetrahydrofolate reductase (MTHFR) C677T variant. Materials and Methods: The study involved 118 women who had two or more spontaneous abortions (SAs) as the case group and 118 women who had at least one live birth but no SA as the control group. Clinical features such as age, body mass index (BMI), medication received, family history of abortion, and thrombophilia were investigated. Real-time PCR was used for genotyping subjects for MTHFR C677T gene polymorphism. Results: Significant differences in age, BMI, and medication received characters have been shown between those in the patients' group. For the MTHFR C677T gene, the genotypes for the patients' group were 36%, 60%, and 4%, whereas the genotypes for the control group were 30%, 58%, and 12%. In addition, the C and T allelic frequencies were 59% and 41% in the healthy control group and 67% and 33% in the patients' group, respectively. A significant association was found between the TT genotype and RSA. A 3.84-fold increased risk of RSA was associated with the TT genotype (odds ratio = 3.84, confidence interval: 1.28-10.93, p-value = 0.02). Conclusions: In this study, homozygosity for the T allele was significantly lower in the RSA-affected than in healthy women, whereas heterozygosity did not vary substantially between the two groups, which was in line with other studies.

[Association of methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and the risk of sporadic colorectal cancer]

Le cancer colorectal (CCR) est un problème majeur de santé publique dans le monde. Le métabolisme des folates est impliqué dans la synthèse, la réparation et la méthylation de de l´ADN. La méthylènetétrahydrofolate réductase (MTHFR) est une enzyme clé dans le métabolisme folique. Un polymorphisme commun de la MTHFR, le C677T, a été corrélé aux CCR. Cette étude cas témoins a été menée pour analyser l´association entre ce polymorphisme et le risque de CCR sporadique dans une population marocaine. Soixante-seize (76) patients atteints de cancer colorectal sporadique confirmé histologiquement et 182 témoins sans antécédents de cancer ont été recrutés pour cette étude. L´ADN a été isolé à partir de sang périphériques et les génotypes ont été déterminés par PCR-RFLP. Le risque d´association a été estimé par le calcul de l´odds ratio (OR) avec un intervalle de confiance à 95%. La fréquence des génotypes MTHFR chez les patients et les témoins a été de 34.1%CC; 56.6%CT; 9.21%TT et 51,6%CC; 42,8% CT; 6% TT respectivement. Le génotype CT et sa combinaison avec le génotype TT et l´allèle T sont associés à un risque accru de CRC avec un OR de 2.02 (avec un intervalle de confiance (IC) de 95%: 1.14-3.58, p = 0,01), de 2.05 (IC 95%: 1.18-3.58, p = 0.01) et de 1.61 (IC 95%: 1,07-2.40, p = 0,02). Les homozygotes TT n´ont pas été un facteur de protection dans notre étude avec un OR de 2,30 (IC 95%: 0.81-6.52, p = 0,11). Il existe une association statistiquement significative entre le variant MTHFR C677T et le risque de survenue de cancer colorectal sporadique dans la population étudiée.

[The study of the association between the C677T polymorphism of the methylenetetrahydrofolate reductase gene and severity of symptoms in patients with schizophrenia]

OBJECTIVE

To study the association of the C677T polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene with the risk of schizophrenia in a large sample, including schizophrenic patients and mentally healthy people, and to investigate the relationship of this polymorphism with the severity of schizophrenia symptoms and genotype-environment interaction effects on these symptoms.

MATERIAL AND METHODS

The sample for genotyping consisted of 1357 patients with schizophrenia and schizophrenia spectrum disorders and 711 people of the control group. The severity of symptoms was assessed with the PANSS. Obstetrical complications and a traumatic brain injury in medical history were studied as environmental factors.

RESULTS AND CONCLUSION

No association was found between MTHFR C677T polymorphism and schizophrenia. There was no genotype effect on the severity of symptoms on the PANSS subscales. The effect of genotype-environment interactions on the severity of schizophrenia symptoms was not detected. The results do not confirm the data of a number of studies on the relationship of MTHFR C677T polymorphism with schizophrenia symptoms.

Investigation of the association between C677T polymorphism of the MTHFR gene and plasma homocysteine level in recurrent fetal miscarriage

AIM

The aim of this study is to determine the association between C677T polymorphism in MTHFR gene and plasma homocysteine concentration in recurrent fetal miscarriages.

METHODS

Overall, 100 women were included in the research, the case group comprised of 50 women who had a history of spontaneously recurrent miscarriage with unspecified cause, and 50 of whom had experienced at least two successful pregnancy, as controls. Methods used in the study included PCR-RFLP with limited effective HinfI enzyme in order to investigate MTHFR polymorphism and enzyme-linked immunosorbent assay analysis to investigate plasma homocysteine concentration.

RESULTS

There was a significant increase in the prevalence of mutant TT genotype among women with miscarriage history. Also, the mean homocysteine level in the case group was significantly higher than that in the control group (P = 0.002) and higher level of homocysteine was found in the carriers of T allele.

CONCLUSION

Our data suggest that C677TT genotype may be a risk factor for miscarriage and CC wild type genotype supposed to have protective effect on hyperhomocysteinemia.

MTHFR C677T polymorphism and risk of nonsyndromic cleft lip with or without cleft palate in the Moroccan population

Background

Nonsyndromic cleft lip with or without cleft palate (NSCL/P) is one of the most common craniofacial malformations observed. Several studies suggest that the decrease in folate has been associated with a higher risk of NSCL/P. The present study aimed to determine the association of 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism gene with the occurrence of NSCL/P in the Moroccan population.

Methods

MTHFR C677T was genotyped in 52 Moroccan patients and 182 unrelated controls, using a PCR followed by restriction fragment length polymorphism.

Results

The results of the study revealed a genotypic and phenotypic distribution in equilibrium with Hardy–Weinberg’s law (χ²=0.36, P=0.55). The frequency of heterozygous genotype C/T and the T allele in controls and patients were 40.7% vs 15.4% and 26%, respectively.

Conclusion

A low association was found between the C677T polymorphism of the MTHFR gene and a risk for the development of NSCL/P in the Moroccan population (OR =0.24, P=0.0005).

Genetic polymorphism of methylenetetrahydrofolate reductase is associated with insulin resistance in Egyptian women with polycystic ovary syndrome

BACKGROUND

A common polymorphism (677C to T; Ala to Val) in the methylenetetrahydrofolate reductase (MTHFR) gene is associated with decreased specific MTHFR activity and elevation of homocysteine. The present study aimed to investigate the association between a single nucleotide polymorphism (SNP) in the MTHFR 677C>T gene and insulin resistance in women with polycystic ovary syndrome (PCOS).

METHODS

Two-hundred patients with PCOS were included in this case-control study: 100 patients with insulin resistance and 100 patients without insulin resistance were genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis.

RESULTS

The TT genotype for the MTHFR 677C>T polymorphism was significantly more frequent in PCOS patients with insulin resistance than in PCOS patients without insulin resistance (19% versus 6%, p = 0.002), whereas there was no significant difference between both groups for CT and there was a statistically significant increase in the T allele in PCOS patients with insulin resistance compared to PCOS patients without insulin resistance (p = 0.002, odds ratio = 1.95 and 95% confidence interval = 1. 29-2.93). Regarding the relationship between MTHFR 677C>T genotypes and the characteristics of insulin resistance in PCOS patients, we found that there was no significant difference in age, waist-hip ratio and total testosterone between the different genotypes of the MTHFR 677C>T polymorphism. The mean values for body mass index and the Homeostatic Model Assessment of Insulin Resistance were significantly higher in the TT genotype of MTHFR 677C>T compared to the CC genotype in PCOS patients with insulin resistance (p < 0.001).

CONCLUSIONS

We have demonstrated an association of the MTHFR 677C>T gene polymorphism with insulin resistance in Egyptian women with PCOS.

Comprehensive analysis of Methylenetetrahydrofolate reductase C677T in younger acute lymphoblastic leukemia patients: A single-center experience

CONTEXT

Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms, mainly the C677T, have been implicated as risk factors for several cancers as the acute lymphoblastic leukemia (ALL). In addition, a potential effect of such variant on the efficacy of methotrexate (MTX) has been reported.

OBJECTIVE

In this study, we evaluated the impact of the C677T variant of MTHFR on MTX-related toxicity in ALL patients from Tunisia; to provide new insights for a personalized therapy based on the human genotype.

MATERIALS AND METHODS

Genotyping was carried out with restriction fragment length polymorphism (RFLP) on blood samples from a total of 35 younger patients; suffering from ALL.

RESULTS

In the ALL patients, the MTHFR 677CT genotype confers a greater risk of toxicity with 1.3 times as relative risk mainly the hepatic toxicity when compared with MTHFR 677CC.

CONCLUSION

Our findings suggest that C677T polymorphism of MTHFR seems to be a good marker for MTX-related toxicity in ALL.

Investigation of Methylenetetrahydrofolate Reductase C677T Polymorphism and Human Papilloma Virus Genotypes in Iranian Breast Cancer

Breast cancer (BC) is the leading cause of death among Iranian women. Development of BC is a multistep process, arising from genetic changes such as methylenetetrahydrofolate reductase (MTHFR) polymorphism and infection with human papillomavirus (HPV). In this study, we investigated HPV genotypes associated with BCs and its relation with MTHFR C677T polymorphism for early detection of familial BCs. A total of 84 archival BC samples from Iran were collected. Verification of each cancer reported in a relative was sought through the pathology reports of the hospital records. Then, DNA was extracted from all samples by standard methods and HPV genotypes and MTHFR C677T polymorphism genotypes were analyzed using multiplex polymerase chain reaction (PCR) and amplification-refractory mutation system (ARMS)-PCR. Finally, data analysis was performed using version 7 of the Epi Info™ 2012 software and test chi-square (x2) for trend. The frequencies of the CC, TC, and TT genotypes of MTHFR (C677T) were 0.53, 0.38, and 0.09 in familial BC patients, and 0.46, 0.51, and 0.03, respectively, in nonfamilial BC patients. Furthermore, HPV DNA typing identified 29 infections and C677T TT genotype was significantly associated with an increased risk of familial BC in the study population. Our results demonstrate that infection with HPV was prevalent among Iranian women with familial BC. Finally, the testing of C677T GG genotype in combination with HPV genotyping as molecular markers can be helpful in the early diagnosis of Iranian familial BCs by PCR.

Association of methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism with autism: evidence of genetic susceptibility

Autism (MIM 209850) is a heterogeneous neurodevelopmental disease that manifests within the first 3 years of life. Numerous articles reported that dysfunctional folate-methionine pathway enzymes may play an important role in the pathophysiology of autism. Methylenetetrahydrofolate reductase (MTHFR) is a critical enzyme of this pathway and MTHFR C677T polymorphism reported as risk factor for autism in several case control studies. However, controversial reports were also published. Hence the present meta-analysis was designed to investigate the relationship of the MTHFR C677T polymorphism with the risk of autism. Electronic databases were searched for case control studies with following search terms - 'MTHFR', 'C677T', in combination with 'Autism'. Pooled OR with its corresponding 95 % CI was calculated and used as association measure to investigate the association between MTHFR C677T polymorphism and risk of autism. Total of thirteen studies were found suitable for the inclusion in the present meta-analysis, which comprises 1978 cases and 7257 controls. Meta-analysis using all four genetic models showed significant association between C677T polymorphism and autism (ORTvs.C = 1.48; 95 % CI: 1.18-1.86; P = 0.0007; ORTT + CT vs. CC = 1.70, 95 % CI = 0.96-2.9, p = 0.05; ORTT vs. CC = 1.84, 95 % CI = 1.12-3.02, p = 0.02; ORCT vs.CC = 1.60, 95 % CI = 1.2-2.1, p = 0.003; ORTT vs.CT+CC = 1.5, 95 % CI = 1.02-2.2, p = 0.03). In total 13 studies, 9 studies were from Caucasian population and 4 studies were from Asian population. The association between C677T polymorphism and autism was significant in Caucasian (ORTvs.C = 1.43; 95 % CI = 1.1-1.87; p = 0.009) and Asian population (ORTvs.C = 1.68; 95 % CI = 1.02-2.77; p = 0.04) using allele contrast model. In conclusion, present meta-analysis strongly suggested a significant association of the MTHFR C677T polymorphism with autism.

Association of MTHFR A1298C polymorphism with conotruncal heart disease

Congenital heart diseases are common congenital anomalies with 1% prevalence worldwide and are associated with significant childhood morbidity and mortality. Among a wide range of aetiologically heterogeneous conditions, conotruncal anomalies account for approximately one-third of all congenital heart defects. The aetiology of conotruncal heart diseases is complex, with both environmental and genetic causes. Hyperhomocysteinaemia, which is often accompanied by the defects of folic acid metabolism, is known to cause conotruncal heart anomalies. In this study, we have evaluated three polymorphisms in the following two hyperhomocysteinaemia-related genes: methylenetetrahydrofolate reductase (MTHFR C677T and A1298C) and nicotinamide N-methyl transferase (NNMT rs694539) in 79 children with conotruncal heart disease and 99 children without conotruncal heart disease. Genotype distribution of the MTHFR A1298C polymorphism showed a statistically significant difference between the two groups. In the case group, AC and CC genotypes were higher than the control group (p<0.05). We have found that MTHFR A1298C polymorphism is associated with conotruncal heart disease; C allele (p=0.028), AC (OR[95% CI]=2.48[1.24-4.95], p=0.010), CC (OR[95% CI]=3.01[1.16-7.83], p=0.023), and AC+CC (OR[95% CI]=2.60[1.36-4.99], p=0.004) genotypes are more frequent in the patient group. Genotype distributions of the MTHFR C677T and NNMT rs694539 polymorphisms were similar in the two groups when evaluated separately and also according to the dominant genetic model (p>0.05). Our results suggest that MTHFR 1298C allele is a risk factor for conotruncal heart disease.

Prevalence of Methylenetetrahydrofolate Reductase C677T Polymorphism in women with Polycystic Ovary Syndrome in southeast of Iran

Background: One of the notable enzymes in the metabolism of folate is Methylenetetrahydrofolate reductase enzyme, this enzyme is necessary for some biological mechanisms. Mutations in the MTHFR gene could reduce the enzyme activity. Aim: The objective of this research was to assess the prevalence of the very general polymorphism, C677T, in females with polycystic ovary syndrome in the southeastern of Iran. Methods: This research was a case-control research and was conducted on 112 PCOS women and 196 healthy controls. Single type nucleotide polymorphisms (SNP) were genotyped by employing the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results: It noticed that in C677T, the pervasiveness of C/ C, C/ T, and T/ T genotypes was 54.5%, 34%, and 11.5%, respectively. The repetition of TT genotype was notably higher in PCOS women contrasted to controls. Conclusions: the appearance of 677T allele could be a danger agent for PCOS susceptibility in the southeast of Iran.

Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism: epidemiology, metabolism and the associated diseases

The Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism is associated with various diseases (vascular, cancers, neurology, diabetes, psoriasis, etc) with the epidemiology of the polymorphism of the C677T that varies dependent on the geography and ethnicity. The 5,10-Methylenetetrahydrofolate reductase (MTHFR) locus is mapped on chromosome 1 at the end of the short arm (1p36.6). This enzyme is important for the folate metabolism which is an integral process for cell metabolism in the DNA, RNA and protein methylation. The mutation of the MTHFR gene which causes the C677T polymorphism is located at exon 4 which results in the conversion of valine to alanine at codon 222, a common polymorphism that reduces the activity of this enzyme. The homozygous mutated subjects have higher homocysteine levels while the heterozygous mutated subjects have mildly raised homocysteine levels compared with the normal, non-mutated controls. Hyperhomocysteinemia is an emerging risk factor for various cardiovascular diseases and with the increasing significance of this polymorphism in view of the morbidity and mortality impact on the patients, further prevention strategies and nutritional recommendations with the supplementation of vitamin B12 and folic acid which reduces plasma homocysteine level would be necessary as part of future health education. This literature review therefore focuses on the recent evidence-based reports on the associations of the MTHFR C677T polymorphism and the various diseases globally.

Comparison of homocysteinemia and MTHFR 677CT polymorphism with Framingham Coronary Heart Risk Score

OBJECTIVE

The Framingham Coronary Heart Disease Risk Score is an important clinical tool. The aim of this cross-sectional study was to compare plasma homocysteine levels and polymorphism 677CT MTHFR with this score to determine the utility of these new biomarkers in clinical practice.

METHODS

Plasma homocysteine levels determined by chemiluminescence and polymorphism 677CT MTHFR, detected by PCR-RFLP, were compared with Framingham coronary risk score in a cross-sectional survey on 68 men and 165 women.

RESULTS

Coronary heart disease risk augmented with an increase in the quartile of plasma homocysteine. In the 2nd, 3rd and 4th quartile of plasma homocysteine, men showed significantly (P<0.001) higher risk than women. For the highest quartile of plasma homocysteine, OR of high-risk (10-year risk≥20%) compared with the lowest quartile was 17.45 (95% CI: 5.79-52.01). Frequencies of CT and TT genotype and T allele were not over-represented in the individuals with score≥10%. The higher plasma homocysteine concentrations in individuals with score≥10% with respect to those with low risk (P<0.005 and P<0.001) were not due to the presence of T allele. The T allele (CT+TT genotypes) of the MTHFR C677T polymorphism was not significantly associated with an increased risk of coronary disease (OR=1.09, 95% CI=0.50-2.39, P=0.844).

CONCLUSIONS

The present study demonstrated an association between plasma homocysteine levels and the severity of coronary heart disease estimated with the Framingham coronary risk score, and this association appeared to be independent on the genotype of MTHFR. We postulate that plasma homocysteine is effective enough, considered even in isolation.

Prevalence of methylenetetrahydrofolate reductase C677T polymorphism in eastern Uttar Pradesh

AIM:

This study was aimed to evaluate the 5, 10-methylenetetrahydrofolate reductase (MTHFR) C677T mutation in eastern Uttar Pradesh population.

MATERIALS AND METHODS:

Polymerase chain reaction (PCR) using specific primers followed by amplicon digestion by Hinf I restriction enzyme was used for MTHFR C677T polymorphism analysis. Total 250 subjects were analyzed.

RESULTS:

The CC genotype was found in 192 subjects, followed by CT in 56 subjects and TT in 2 subject. Genotype frequencies of CC, CT and TT were 0.768, 0.224 and 0.008, respectively. The frequency of C allele was found to be 0.88 and that of T allele was 0.12.

CONCLUSION:

It is evident from the results of the present study that the percentage of homozygous genotype (CC) is highest in the target population.

The Frequency of A1298C and C677T Polymorphisms of the Methylentetrahydrofolate Gene in Turkish Patients with Rheumatoid Arthritis: Relationship with Methotrexate Toxicity

The C677T and A1298C polymorphisms of methylenetatrahydrofolate reductase (MTHFR) gene are reported to have a relationship to methotrexate (MTX) metabolism, with conflicting results. The aim of this study was to determine the frequency of MTHFR C677 T and A1298C gene polymorphisms in a group of Turkish RA patients and evaluate its association with MTX toxicity.

Sixty-four patients with RA and 31 control subjects with a mean age of 48.7 ±12.5 and 46.2 ± 13.4 years, were enrolled to the study. Demographic characteristics were obtained and MTX-related adverse effects were recorded in the patient group. The A1298C and C677T polymorphisms of the MTHFR gene were analyzed and the distribution of genotypes according side effects, were determined.

The frequency of MTHFR C677T and A1298C polymorphisms were similar in the patient and control groups. Folic acid supplementation with a mean dose of 5mg folic acid/week, was present in all patients. Thirty-six of the 64 patients showed adverse effects to MTX treatment, and MTX had been discontinued in 12 (18.8%) patients due to side effects and/or inefficacy. MTHFR C677T and A1298C gene polymorphisms were found to be similar in patients with and without MTX-related adverse events.

In conclusion, A1298C and C677T polymorphisms in the MTHFR gene, were not related with MTX-related toxicity in RA patients receiving folate supplementation. Further studies are needed to illuminate the polymorphisms in other enzymes that might be responsible from the MTX toxicity in patients suffering from RA.