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Sample records for reductase mthfr mutation

  1. Cerebral sinovenous thrombosis associated with MTHFR A1298C mutation in the newborn: a case report.

    PubMed

    Cizmeci, Mehmet Nevzat; Kanburoglu, Mehmet Kenan; Akelma, Ahmet Zulfikar; Donmez, Ahsen; Sonmez, Fatma Mujgan; Polat, Aziz; Kosehan, Dilek; Tatli, Mustafa Mansur

    2013-02-01

    Although cerebral sinovenous thrombosis (CSVT) is a rare condition in the neonatal period, high rates of morbidity and mortality necessitate the establishment of an early diagnosis. Methylenetetrahydrofolate reductase (MTHFR) plays a central role in the folate cycle and mutations of MTHFR are associated with vascular disease. While the C677T common missense mutation is the most well-defined MTHFR polymorphism, another common missense mutation, A1298C also exists. There has been no reported case of CSVT associated with MTHFR A1298C mutation in the neonatal period. Herein, we report a neonate with CSVT who was found to have MTHFR A1298C homozygosity. PMID:22797907

  2. Common Mutations of the Methylenetetrahydrofolate Reductase (MTHFR) Gene in Non-Syndromic Cleft Lips and Palates Children in North-West of Iran

    PubMed Central

    Abdollahi-Fakhim, Shahin; Asghari Estiar, Mehrdad; Varghaei, Parizad; Alizadeh Sharafi, Mahdi; Sakhinia, Masoud; Sakhinia, Ebrahim

    2015-01-01

    Introduction: Cleft lips and cleft palates are common congenital abnormalities in children. Various chromosomal loci have been suggested to be responsible the development of these abnormalities. The present study was carried out to investigate the association between the suspected genes (methylenetetrahydrofolate reductase [MTHFR] A1298C and C677T) that might contribute into the etiology of these disorders through application of molecular methods. Materials and Methods: This cross-sectional and explanatory study was carried out on a study population of 65 affected children, 130 respective parents and 50 healthy individuals between 2009 and 2012 at Tabriz University of Medical Sciences, IR Iran. After DNA extraction, amplification refractory mutation systempolymerase chain reaction (ARMS-PCR) and restriction fragment length polymorphism (RFLP)-PCR were used respectively to investigate the C677T and A1298C mutations for the MTHFR gene. Results: There was a significant difference in the rates of the C677T mutation when affected patients and their fathers were compared with the control group (odds ratio [OR]=0.44) (OR=0.64). However, there was no significant difference observed in the rate of this mutation between the patients mothers and the control group (OR=1.35). In addition, the abnormality rate was higher in patients with the A1298C mutation and their parents, when compared with the control group. This abnormality rate was higher for the affected children and their fathers in comparison with their mothers (Fathers, OR=0.26; Mothers, OR=0.65; Children, OR=0.55). No significant difference was seen in the rate of the polymorphism C677T in its CC, when the affected children and their parents were compared with the control group. However, there was a significant difference in the A1298C mutation. Conclusion: An association was seen between the A1298C mutation and cleft lip and cleft palate abnormalities in Iran. However, there seems to be a stronger relationship between the C67TT mutation and these abnormalities in other countries, which could be explained by racial differences. Moreover, this association was more notable between the affected children and their fathers than their mothers. The findings in this study may be helpful in future studies and screening programs. PMID:25745606

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

    PubMed

    Liew, Siaw-Cheok; Gupta, Esha Das

    2015-01-01

    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. PMID:25449138

  4. MTHFR Gene Mutations: A Potential Marker of Late-Onset Alzheimer's Disease?

    PubMed

    Romn, Gustavo C

    2015-01-01

    Recent epigenome-wide association studies have confirmed the importance of epigenetic effects mediated by DNA methylation in late-onset Alzheimer's disease (LOAD). Metabolic folate pathways and methyl donor reactions facilitated by B-group vitamins may be critical in the pathogenesis of LOAD. Methylenetetrahydrofolate reductase (MTHFR) gene mutations were studied in consecutive Alzheimer's Disease & Memory Clinic patients up to December 2014. DNA analyses of MTHFR-C667T and - A1298C homozygous and heterozygous polymorphisms in 93 consecutive elderly patients revealed high prevalence of MTHFR mutations (92.5%). Findings require confirmation in a larger series, but MTHFR mutations may become a LOAD marker, opening novel possibilities for prevention and treatment. PMID:26401555

  5. Bilateral transverse sinus thrombosis secondary to a homozygous C677T MTHFR gene mutation.

    PubMed

    Kanaan, Ziad M; Mahfouz, Rami; Taher, Ali; Sawaya, Raja A

    2008-09-01

    We describe the case of a previously healthy young man who presented with headache, diplopia, nausea, vomiting, and bilateral papilledema. Magnetic resonance venography of the brain revealed thrombosis of the right transverse sinus. Blood tests showed elevated homocysteine levels, and coagulation studies revealed a homozygous C677T mutation and a heterozygous A1298C mutation of the methylenetetrahydrofolate reductase (MTHFR) gene. The patient had no other etiology for venous thrombosis. We recommend screening patients who present with sinus thrombosis for MTHFR gene mutations. PMID:18666857

  6. Internal jugular vein thrombosis due to heterozygote methylene tetrahydrofolate reductase (MTHFR) 1298C and Factor V G1691A mutations after a minor trauma

    PubMed Central

    Gumussoy, Murat; Arslan, Ilker B.; Cukurova, Ibrahim; Uluyol, Sinan

    2014-01-01

    Internal jugular vein thrombosis usually appears in central venous catheterization, distant malignancies, hypercoagulation, infections, or secondary to ovarian hyperstimulation syndrome. A 44-year-old female patient presented to us with sore throat, and pain and swelling on the right side of her neck. She had a history of simple neck trauma 10 days ago. Ultrasonography and computed tomography showed bilateral multiple lymphadenopathies and right internal jugular vein thrombosis. Patient was put on parenteral antibiotherapy and oral anticoagulant treatment. Genomic DNA tests for hypercoagulation revealed methylene tetrahydrofolate reductase 1298C heterozygote mutation and Factor V G1691A (Leiden) mutation. Patient has been under clinical control for 1 year and does not have any complaints. In this article, diagnosis, treatment, and the etiology of internal jugular vein thrombosis, which is a rare and potentially fatal condition, have been discussed through this case. PMID:25937730

  7. Coexistence of Neurofibromatosis Type-1 and MTHFR C677T Gene Mutation in a Young Stroke Patient: A Case Report

    PubMed Central

    Yilmaz, Halim; Erkin, Gulten; Gumus, Haluk; Nalbant, Lutfiye

    2013-01-01

    In neurofibromatosis type-1 (NF1), cerebrovascular disorders are rarely encountered although vasculopathy is a well-known complication. Several mutations seen in methylenetetrahydrofolate reductase (MTHFR) give rise to the formation of hyperhomocysteinemia and homocystinuria, a considerable risk factor for cardiovascular and cerebrovascular disorders, by leading to enzymatic inactivation. In the paper, a 31-year-old young stroke female patient with the coexistence of neurofibromatosis and MTHFR C677T gene mutation was presented. PMID:23533858

  8. Methylene tetrahydrofolate reductase (MTHFR) gene polymorphisms in chronic myeloid leukemia: an Egyptian study.

    PubMed

    Khorshied, Mervat Mamdooh; Shaheen, Iman Abdel Mohsen; Abu Khalil, Reham E; Sheir, Rania Elsayed

    2014-01-01

    Methylenetetrahydrofolate reductase (MTHFR) gene plays a pivotal role in folate metabolism. Several genetic variations in MTHFR gene as MTHFR-C677T and MTHFR-A1298C result in decreased MTHFR activity, which could influence efficient DNA methylation and explain susceptibility to different cancers. The etiology of chronic myeloid leukemia (CML) is obscure and little is known about individual's susceptibility to CML. In order to assess the influence of these genetic polymorphisms on the susceptibility to CML and its effect on the course of the disease among Egyptians, we performed an age-gender-ethnic matched case-control study. The study included 97 CML patients and 130 healthy controls. Genotyping of MTHFR-C677T and -A1298C was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. The results showed no statistical difference in the distribution of MTHFR-C677T and -A1298C polymorphic genotypes between CML patients and controls. The frequency of MTHFR 677-TT homozygous variant was significantly higher in patients with accelerated/blastic transformation phase when compared to those in the chronic phase of the disease. In conclusion, our study revealed that MTHFR-C677T and -A1298C polymorphisms could not be considered as genetic risk factors for CML in Egyptians. However, MTHFR 677-TT homozygous variant might be considered as a molecular predictor for disease progression. PMID:24338216

  9. Mutation Update and Review of Severe Methylenetetrahydrofolate Reductase Deficiency.

    PubMed

    Froese, D Sean; Huemer, Martina; Suormala, Terttu; Burda, Patricie; Coelho, David; Guéant, Jean-Louis; Landolt, Markus A; Kožich, Viktor; Fowler, Brian; Baumgartner, Matthias R

    2016-05-01

    Severe 5,10-methylenetetrahydrofolate reductase (MTHFR) deficiency is caused by mutations in the MTHFR gene and results in hyperhomocysteinemia and varying severity of disease, ranging from neonatal lethal to adult onset. Including those described here, 109 MTHFR mutations have been reported in 171 families, consisting of 70 missense mutations, 17 that primarily affect splicing, 11 nonsense mutations, seven small deletions, two no-stop mutations, one small duplication, and one large duplication. Only 36% of mutations recur in unrelated families, indicating that most are "private." The most common mutation is c.1530A>G (numbered from NM_005957.4, p.Lys510 = ) causing a splicing defect, found in 13 families; the most common missense mutation is c.1129C>T (p.Arg377Cys) identified in 10 families. To increase disease understanding, we report enzymatic activity, detected mutations, and clinical onset information (early, <1 year; or late, >1 year) for all published patients available, demonstrating that patients with early onset have less residual enzyme activity than those presenting later. We also review animal models, diagnostic approaches, clinical presentations, and treatment options. This is the first large review of mutations in MTHFR, highlighting the wide spectrum of disease-causing mutations. PMID:26872964

  10. Methylenetetrahydrofolate reductase mutations, a genetic cause for familial recurrent neural tube defects

    PubMed Central

    Yaliwal, Laxmi V.; Desai, Rathnamala M.

    2012-01-01

    Methylenetetrahydrofolate reductase (MTHFR) gene mutations have been implicated as risk factors for neural tube defects (NTDs). The best-characterized MTHFR genetic mutation 677C→T is associated with a 2–4 fold increased risk of NTD if patient is homozygous for this mutation. This risk factor is modulated by folate levels in the body. A second mutation in the MTHFR gene is an A→C transition at position 1298. The 1298A→C mutation is also a risk factor for NTD, but with a smaller relative risk than 677C→T mutation. Under conditions of low folate intake or high folate requirements, such as pregnancy, this mutation could become of clinical importance. We present a case report with MTHFR genetic mutation, who presented with recurrent familial pregnancy losses due to anencephaly/NTDs. PMID:22754237

  11. Association between 5, 10-methylenetetrahydrofolate reductase (MTHFR) polymorphisms and congenital heart disease: A meta-analysis☆

    PubMed Central

    Wang, Wenju; Hou, Zongliu; Wang, Chunhui; Wei, Chuanyu; Li, Yaxiong; Jiang, Lihong

    2013-01-01

    Background Inconsistent results were reported in recent literature regarding the association between methylenetetrahydrofolate reductase (MTHFR) C677T/A1298C polymorphisms and the susceptibility of congenital heart disease (CHD). In this study, we performed a meta-analysis to investigate the associations by employing multiple analytical methods. Methods Literature search was performed and published articles were obtained from PubMed, Embase and CNKI databases based on the exclusion and inclusion criteria. Data were extracted from eligible studies and the crude odds ratios and their corresponding 95% confidence intervals (CIs) were calculated using random or fix effects model to evaluate the associations between the MTHFR C677T/A1298C polymorphisms and CHD development. Subgroup based analysis was performed by Hardy–Weinberg equilibrium, ethnicity, types of CHD, source of control and sample size. Results Twenty-four eligible studies were included in this meta-analysis. Significant association was found between fetal MTHFR C677T polymorphism and CHD development in all genetic models. The pooled ORs and 95% CIs in all genetic models indicated that MTHFR C677T polymorphism was significantly associated with CHD in Asian, but not Caucasian in subgroup analysis. The maternal MTHFR C677T polymorphism was not associated with CHD except for recessive model. Moreover, neither maternal nor fetal MTHFR A1298C polymorphism was associated with CHD. Conclusion The fetal MTHFR C677T polymorphism may increase the susceptibility to CHD. Fetal MTHFR C677T polymorphism was more likely to affect Asian fetus than Caucasian. The MTHFR A1298C polymorphism may not be a risk of congenital heart disease. PMID:25606381

  12. Methylenetetrahydrofolate reductase (MTHFR) polymorphism susceptibility to schizophrenia and bipolar disorder: an updated meta-analysis.

    PubMed

    Hu, Cai-Yun; Qian, Zhen-Zhong; Gong, Feng-Feng; Lu, Shan-Shan; Feng, Fang; Wu, Yi-Le; Yang, Hui-Yun; Sun, Ye-Huan

    2015-02-01

    Previous studies examining the possible role of the methylenetetrahydrofolate reductase (MTHFR) polymorphisms in the development of schizophrenia (SZ) and bipolar disorder (BPD) have provided inconclusive findings, this meta-analysis was therefore designed to get a more reliable assessment. A total of 38 articles were identified through a search of electronic databases, up to 27 February 2014. Odds ratios (ORs) with 95% confidence interval (CIs) were calculated using random effects models. Meta-analysis showed that MTHFR C677T was significantly associated with SZ, the highest OR was found for the recessive model (for TT vs. CT + CC: OR = 1.34, 95% CI: 1.18-1.53); a marginal association of MTHFR C677T with increased risk of BPD has also been found for the recessive model (OR = 1.26, 95% CI: 1.00-1.59). Subgroup analysis by ethnicity indicated that the significant association with SZ and BPD existed among Asian and African populations, but not for the white. MTHFR A1298C was significant associated with SZ, the highest OR for the dominant model (OR = 1.13, 95% CI: 1.03-1.24). Subgroup analysis indicated a significant association with SZ existed in Asian populations, not among the white populations and no significant association was detected between the MTHFR A1298C and BPD in all groups. We conclude that MTHFR polymorphism is associated with SZ and BPD among Asian, African populations, but not the white. PMID:24938371

  13. Association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and age of onset in schizophrenia.

    PubMed

    Vares, Maria; Saetre, Peter; Deng, Hong; Cai, Guiqing; Liu, Xiehe; Hansen, Thomas; Rasmussen, Henrik B; Werge, Thomas; Melle, Ingrid; Djurovic, Srdjan; Andreassen, Ole A; Agartz, Ingrid; Hall, Hkan; Terenius, Lars; Jnsson, Erik G

    2010-03-01

    Different lines of evidence indicate that methylenetetrahydrofolate reductase (MTHFR) functional gene polymorphisms, causative in aberrant folate-homocysteine metabolism, are associated with increased vulnerability to several heritable developmental disorders. Opposing views are expressed considering the possible association between MTHFR and susceptibility for schizophrenia. In order to evaluate if age of onset could explain some of this discrepancy we investigated the relationship between two functional MTHFR gene polymorphisms and age at onset in this disorder. Scandinavian patients (n = 820) diagnosed with schizophrenia, schizoaffective disorder, and schizophreniform disorder were investigated. Two functional MTHFR single nucleotide polymorphisms (SNPs; rs1801131 and rs1801133) were genotyped and the effect of MTHFR polymorphisms on the age of onset was examined with survival analysis. In an attempt to replicate the findings from the Scandinavian sample, the association between rs1801133 and age at onset was also analyzed in Chinese high-risk families, with two or more affected siblings (n = 243). Among the Scandinavian patients the functional MTHFR SNP rs1801133 (C677T) significantly affected age at onset of schizophrenia in a dose-dependent manner (P = 0.0015), with lower age of onset with increasing numbers of the mutant T-allele. There was no evidence of rs1801131 (A1298C) affecting age of onset in schizophrenia. Within the Chinese high-risk families carriers of the MTHFR 677T allele showed earlier age at onset than siblings being homozygous for the wild-type allele (P = 0.008). The MTHFR C677T polymorphism may play a role as a modifying factor for age of onset in schizophrenia. PMID:19746410

  14. Plasma folate, methylenetetrahydrofolate reductase (MTHFR), and colorectal cancer risk in three large nested case-control studies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Few prospective studies have examined the associations between blood levels of folate, in conjunction with methylenetetrahydrofolate reductase (MTHFR) polymorphisms, and colorectal cancer. We evaluated the associations between plasma folate, MTHFR C677T, and A1298C, and colorectal cancer in three la...

  15. Is methylenetetrahydrofolate reductase (MTHFR) gene A1298C polymorphism related with varicocele risk?

    PubMed

    Ucar, V B; Nami, B; Acar, H; Kilinç, M

    2015-02-01

    Varicocele is one of the main reasons for male infertility the exact aetiology of which remains unclear. Methylenetetrahydrofolate reductase (MTHFR) is important for DNA synthesis and methylation, which has a key role during spermatogenesis. Numerous literature suggests that the MTHFR polymorphism may be genetic risk factors for male infertility. In this study, we evaluated C677T and A1298C MTHFR gene polymorphism frequency in patients with varicocele and normal men. A total of 107 varicocele patients and 109 fertile healthy individuals were included. Genotyping of the MTHFR gene in C677T and A1298C base pairs carried out by using real-time PCR technique and afterwards, the statistical analysis accomplished. There is a statistical difference for the frequency of 1298AA genotype in patients with varicocele compared with normal controls (P = 0.0051, OR = 2.2750). Instead, subsequently, 1298/A allel frequency in patient group was significantly higher in comparison with control group (P = 0.0174). According to our results, 1298AA genotype in MTHFR gene raises the risk of varicocele approximately 2.3 times more compared with men carrying other genotypes. The results show that genetic factors have an important role in the molecular basis of varicocele. PMID:24456105

  16. Association of C677T transition of the human methylenetetrahydrofolate reductase (MTHFR) gene with male infertility.

    PubMed

    Karimian, Mohammad; Colagar, Abasalt Hosseinzadeh

    2016-04-01

    The human methylenetetrahydrofolate reductase (MTHFR) gene encodes one of the key enzymes in folate metabolism. This gene is located on chromosome 1 (1p36.3), which has 12 exons. The aim of the present study was to investigate the possible association of the two (C677T and A1298C) polymorphisms of this gene with male infertility. In a case-control study, 250 blood samples were collected from IVF centres in Sari and Babol (Iran): 118 samples were from oligospermic men and 132 were from controls. Two single nucleotide polymorphisms of the MTHFR genotype were detected using polymerase chain reaction-restriction fragment length polymorphism. There was no association found between the A1298C variant and male infertility. However, carriers of the 677T allele (CT and TT genotypes) were at a higher risk of infertility than individuals with other genotypes (odds ratio 1.84; 95% confidence interval 1.11-3.04; P=0.0174). Structural analysis of human MTHFR flavoprotein showed that C677T transition played an important role in the change in affinity of the MTHFR-Flavin adenine dinucleotide binding site. Based on our results, we suggest that C677T transition in MTHFR may increase the risk of male infertility, and detection of the C677T polymorphism biomarker may be helpful in the screening of idiopathic male infertility. PMID:25412139

  17. Retinal Ganglion Cell Loss and Mild Vasculopathy in Methylene Tetrahydrofolate Reductase (Mthfr)-Deficient Mice: A Model of Mild Hyperhomocysteinemia

    PubMed Central

    Markand, Shanu; Saul, Alan; Roon, Penny; Prasad, Puttur; Martin, Pamela; Rozen, Rima; Ganapathy, Vadivel; Smith, Sylvia B.

    2015-01-01

    Purpose. Methylenetetrahydrofolate reductase (Mthfr) is a key enzyme in homocysteine-methionine metabolism. We investigated Mthfr expression in retina and asked whether mild hyperhomocysteinemia, due to Mthfr deficiency, alters retinal neurovascular structure and function. Methods. Expression of Mthfr was investigated at the gene and protein level using quantitative (q) RT-PCR, in situ hybridization, immunoblotting, and immunohistochemistry (IHC). The Mthfr+/+ and Mthfr+/? mice were subjected to comprehensive evaluation using ERG, funduscopy, fluorescein angiography (FA), spectral-domain optical coherence tomography (SD-OCT), HPLC, and morphometric and IHC analysis of glial fibrillary acidic protein (GFAP) at 8 to 24 weeks. Results. Gene and protein analyses disclosed widespread retinal expression of Mthfr. Electroretinography (ERG) revealed a significant decrease in positive scotopic threshold response in retinas of Mthfr+/? mice at 24 weeks. Fundus examination in mice from both groups was normal; FA revealed areas of focal vascular leakage in 20% of Mthfr+/? mice at 12 to 16 weeks and 60% by 24 weeks. The SD-OCT revealed a significant decrease in nerve fiber layer (NFL) thickness at 24 weeks in Mthfr+/? compared to Mthfr+/+ mice. There was a 2-fold elevation in retinal hcy at 24 weeks in Mthfr+/? mice by HPLC and IHC. Morphometric analysis revealed an approximately 20% reduction in cells in the ganglion cell layer of Mthfr+/? mice at 24 weeks. The IHC indicated significantly increased GFAP labeling suggestive of Mller cell activation. Conclusions. Mildly hyperhomocysteinemic Mthfr+/? mice demonstrate reduced ganglion cell function, thinner NFL, and mild vasculopathy by 24 weeks. The retinal phenotype is similar to that of hyperhomocysteinemic mice with deficiency of cystathionine-?-synthase (Cbs) reported earlier. The data support the hypothesis that hyperhomocysteinemia may be causative in certain retinal neurovasculopathies. PMID:25766590

  18. Associations between Methylenetetrahydrofolate Reductase (MTHFR) Polymorphisms and Non-Alcoholic Fatty Liver Disease (NAFLD) Risk: A Meta-Analysis

    PubMed Central

    Sun, Man-Yi; Zhang, Li; Shi, Song-Li; Lin, Jing-Na

    2016-01-01

    Background C677T and A1298C are the most common allelic variants of Methylenetetrahydrofolate Reductase (MTHFR) gene. The association between MTHFR polymorphisms and the occurrence of non-alcoholic fatty liver disease (NAFLD) remains controversial. This study was thus performed to examine whether MTHFR mutations are associated with the susceptibility to NAFLD. Methods A first meta-analysis on the association between the MTHFR polymorphisms and NAFLD risks was carried out via Review Manager 5.0 and Stata/SE 12.0 software. The on-line databases, such as PubMed, EMBASE, CENTRAL, WOS, Scopus and EBSCOhost (updated to April 1st, 2016), were searched for eligible case-control studies. The odd radio (OR), 95% confidence interval (CI) and P value were calculated through Mantel-Haenszel statistics under random- or fixed-effect model. Results Eight articles (785 cases and 1188 controls) contributed data to the current meta-analysis. For C677T, increased NAFLD risks were observed in case group under homozygote model (T/T vs C/C, OR = 1.49, 95% CI = 1.03~2.15, P = 0.04) and recessive model (T/T vs C/C+C/T, OR = 1.42, 95% CI = 1.07~1.88, P = 0.02), but not the other genetics models, compared with control group. For A1298C, significantly increased NAFLD risks were detected in allele model (C vs A, OR = 1.53, 95% CI = 1.13~2.07, P = 0.006), homozygote model (C/C vs A/A, OR = 2.81, 95% CI = 1.63~4.85, P = 0.0002), dominant model (A/C+C/C vs A/A, OR = 1.60, 95% CI = 1.06~2.41, P = 0.03) and recessive model (C/C vs A/A+A/C, OR = 2.08, 95% CI = 1.45~3.00, P<0.0001), but not heterozygote model. Conclusion T/T genotype of MTHFR C677T polymorphism and C/C genotype of MTHFR A1298C are more likely to be associated with the susceptibility to NAFLD. PMID:27128842

  19. Seven novel mutations in the methylenetetrahydrofolate reductase gene and genotype/phenotype correlations in severe methylenetetrahydrofolate reductase deficiency

    SciTech Connect

    Goyette, P.; Frosst, P.; Rosenblatt, D.S.; Rozen. R.

    1995-05-01

    5-Methyltetrahydrofolate, the major form of folate in plasma, is a carbon donor for the remethylation of homocysteine to methionine. This form of folate is generated from 5,10-methylenetetrahydrofolate through the action of 5,10-methylenetetrahydrofolate reductase (MTHFR), a cytosolic flavoprotein. Patients with an autosomal recessive severe deficiency of MTHFR have homocystinuria and a wide range of neurological and vascular disturbances. We have recently described the isolation of a cDNA for MTHFR and the identification of two mutations in patients with severe MTHFR deficiency. We report here the characterization of seven novel mutations in this gene: six missense mutations and a 5{prime} splice-site defect that activates a cryptic splice in the coding sequence. We also present a preliminary analysis of the relationship between genotype and phenotype for all nine mutations identified thus far in this gene. A nonsense mutation and two missense mutations (proline to leucine and threonine to methionine) in the homozygous state are associated with extremely low activity (0%-3%) and onset of symptoms within the 1st year of age. Other missense mutations (arginine to cysteine and arginine to glutamine) are associated with higher enzyme activity and later onset of symptoms. 19 refs., 4 figs., 2 tabs.

  20. Neonatal and Fetal Methylenetetrahydrofolate Reductase Genetic Polymorphisms: An Examination of C677T and A1298C Mutations

    PubMed Central

    Isotalo, Phillip A.; Wells, George A.; Donnelly, James G.

    2000-01-01

    Methylenetetrahydrofolate reductase (MTHFR) mutations are commonly associated with hyperhomocysteinemia, and, through their defects in homocysteine metabolism, they have been implicated as risk factors for neural tube defects and unexplained, recurrent embryo losses in early pregnancy. Folate sufficiency is thought to play an integral role in the phenotypic expression of MTHFR mutations. Samples of neonatal cord blood (n=119) and fetal tissue (n=161) were analyzed for MTHFR C677T and A1298C mutations to determine whether certain MTHFR genotype combinations were associated with decreased in utero viability. Mutation analysis revealed that all possible MTHFR genotype combinations were represented in the fetal group, demonstrating that 677T and 1298C alleles could occur in both cis and trans configurations. Combined 677CT/1298CC and 677TT/1298CC genotypes, which contain three and four mutant alleles, respectively, were not observed in the neonatal group (P=.0402). This suggests decreased viability among fetuses carrying these mutations and a possible selection disadvantage among fetuses with increased numbers of mutant MTHFR alleles. This is the first report that describes the existence of human MTHFR 677CT/1298CC and 677TT/1298CC genotypes and demonstrates their potential role in compromised fetal viability. PMID:10958762

  1. Genetic variants in 3′-UTRs of methylenetetrahydrofolate reductase (MTHFR) predict colorectal cancer susceptibility in Koreans

    PubMed Central

    Joo Jeon, Young; Woo Kim, Jong; Mi Park, Hye; Kim, Jung O; Geun Jang, Hyo; Oh, Jisu; Gyu Hwang, Seong; Won Kwon, Sung; Oh, Doyeun; Keun Kim, Nam

    2015-01-01

    Polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) play important roles in tumor development, progression, and metastasis. Moreover, recent studies have reported that a number of 3′-UTR polymorphisms potentially bind to specific microRNAs in a variety of cancers. The aim of this study was to investigate the association of four MTHFR polymorphisms, 2572C>A [rs4846049], 4869C>G [rs1537514], 5488C>T [rs3737967], and 6685T>C [rs4846048] with colorectal cancer (CRC) in Koreans. A total of 850 participants (450 CRC patients and 400 controls) were enrolled in the study. The genotyping of MTHFR 3′-UTR polymorphisms was performed by polymerase chain reaction-restriction fragment length polymorphism analysis or TaqMan allelic discrimination assay. We found that MTHFR 2572C>A, 4869C>G, and 5488C>T genotypes were substantially associated with CRC susceptibility. Of the potentially susceptible polymorphisms, MTHFR 2572C>A was associated with increased homocysteine and decreased folate levels in the plasma based on MTHFR 677CC. Our study provides the evidences for 3′-UTR variants in MTHFR gene as potential biomarkers for use in CRC prevention. PMID:26046315

  2. Evidence of Paternal N5, N10 - Methylenetetrahydrofolate Reductase (MTHFR) C677T Gene Polymorphism in Couples with Recurrent Spontaneous Abortions (RSAs) in Kolar District- A South West of India

    PubMed Central

    Vanilla, Shiny; Kotur, Pushpa F; Kutty, Moideen A; Vegi, Pradeep Kumar

    2015-01-01

    Introduction: Recurrent spontaneous abortion (RSA) is a multifactorial clinical obstetrics complication commonly occurring in pregnancy. Many research studies have noted the mutations such as C677T in N5, N10 - Methylenetetrahydrofolate reductase (MTHFR)gene which is regarded as RSA risk factor. This study was carried out to determine the occurrence of frequency of C677T of the MTHFR gene mutations with RSA. Aim: The purpose of present study is to determine the frequency of MTHFR C677T polymorphisms in couples with recurrent pregnancy loss and the impact of paternal polymorphisms of MTHFR C677T in recurrent pregnancy loss in population of couples living in Kolar district of Karnataka with RSA. Design: A total of 15 couples with a history of two or more unexplained RSA were enrolled as subjects in the study and a total of 15 couples with normal reproductive history, having two or more children and no history of miscarriages were enrolled as controls. Materials and Methods: DNA extraction from samples case and control group couples and its quantification by Agarose gel electrophoresis, assessment of DNA purity, MTHFR C 677T gene mutation detection by PCR-RFLP method. Statistical analysis: Carried out by web based online SPSS tool. Results: The frequency of C677T genotype showed homozygous wild type CC (80%), heterozygous CT type (13.3%) and homozygous mutation TT type (6.67%) observed in males. Similarly from females homozygous wild type CC (86.6%), heterozygous type (13.3%), and homozygous type mutations TT (0%) was recorded. In couple control groups, we observed homozygous wild type CC (86.6%), heterozygous CT type (13.3%) and homozygous type mutations TT type (0%). Conclusion: We noticed a high frequency of MTHFR specifically T allele associated with paternal side.Therefore, the present study indicated the impact of paternal gene polymorphism of MTHFR C677T on screening in couples with recurrent pregnancy loss. PMID:25859445

  3. Severe arterial thrombophilia associated with a homozygous MTHFR gene mutation (A1298C) in a young man with Klinefelter syndrome.

    PubMed

    Ozbek, Mustafa; Oztrk, M Akif; Ureten, Kemal; Ceneli, Ozcan; Erdogan, Mehmet; Haznedaroglu, Ibrahim C

    2008-07-01

    Klinefelter syndrome (KS) is the most common sex chromosome disorder in men. It may be associated with an increased risk for venous thrombosis and thromboembolism, which is partially explained by hypofibrinolysis due to androgen deficiency. Additional genetic or acquired thrombophilic states have been shown in KS patients complicated with venous thrombosis as isolated case reports. Arterial thrombotic events had not been previously reported in KS. In this study, a young man with KS who developed acute arterial thrombosis during testosterone replacement therapy is presented. He was homozygous for the A1298C mutation of the methylenetetrahydrofolate reductase (MTHFR) gene. PMID:18160591

  4. Serum Folate and Methylenetetrahydrofolate Reductase (MTHFR) C677T Polymorphism Adjusted for Folate Intake

    PubMed Central

    Nishio, Kazuko; Goto, Yasuyuki; Kondo, Takaaki; Ito, Shimon; Ishida, Yoshiko; Kawai, Sayo; Naito, Mariko; Wakai, Kenji; Hamajima, Nobuyuki

    2008-01-01

    Background Serum folate concentration is lower in individuals with the methylenetetrahydrofolate reductase (MTHFR) 677TT genotype than in those with the MTHFR 677CC or 677CT genotypes. Since studies considering folate intake are limited, we examined the association between folate intake and serum folate levels, according to the genotype. Methods The subjects comprised 170 Japanese persons (74 males and 96 females) aged 20-75 years who visited a clinic to test for Helicobacter pylori infection. Folate intake was estimated using a semiquantitative food-frequency questionnaire, and serum folate was measured in the residual fasting blood samples of the subjects. MTHFR C677T was genotyped using polymerase chain reaction. Results The geometric means of serum folate level were 6.19, 6.20, and 5.17 ng/mL among the 60 participants with the 677CC genotype, 90 participants with the 677CT genotype, and 20 participants with the 677TT genotype, respectively. No difference was noted in the mean folate intake estimated using the food-frequency questionnaire. Regression analysis showed that loge(serum folate) adjusted for age, sex, and loge(folate intake) was significantly lower among those with the 677TT genotype than among those with the 677CT or 677CC genotypes (p = 0.01). The adjusted reduction in serum folate was 20.2% (95% confidence interval, 5.4-32.6%) in the case of the 677TT genotype relative to the levels in the case of the 677CC/677CT genotypes. When folate intake was adjusted for total energy intake, using the residual method, the slope of the regression line for 677TT was smaller than those of the regression lines for 677CC and 677CT. Conclusion Individuals with the 677TT genotype may need to consume more folate to maintain serum folate levels similar to those found in individuals with the 677CC/677CT genotypes. PMID:18480590

  5. Association between methylenetetrahydrofolate reductase (MTHFR) polymorphism and carotid intima medial thickness progression in post ischaemic stroke patient

    PubMed Central

    Faradz, Sultana M.H.; Sari, Stefani; Hadisaputro, Soeharyo

    2015-01-01

    Background Hyperhomocysteinemia is associated with an increased risk of atherosclerosis. The main cause of elevated levels of homocysteine is 677T allele, the gene encoded by methylenetetrahydrofolate reductase (MTHFR). Carotid atherosclerosis progression, which can be measured by examination of carotid intima-media thickness (C-IMT), is a predictor of recurrent ischemic stroke. The objective of this study was to determine a relationship between MTHFR polymorphism, homocysteine ​​levels, and increased C-IMT in post- ischemic stroke patients. Methods This was an epidemiological prospective observational cohort study involving 71 patients with post-ischemic stroke subject of the first (onset 1 month) admitted in the Neurology Clinic of Kariadi Hospital during 2012 to 2013. C-IMT was examined using carotid duplex ultrasound at 1st, 6th, and 12th month after stroke onset. MTHFR gene polymorphism was examined using polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP). Homocysteine level was measured using Axis® Homocysteine EIA. Results We found 3 categories of MTHFR gene variation, i.e., 677T/T, 677T/C, and 677C/C. The most frequent allele was MTHFR 677C (88.9%), while the MTHFR 677T allele frequency was 11.1%. The majority allele of the subject population was 677C/C, however, there were 3 subjects (4.2%) who had 677T/T allele. The 677T/T allele group had normal homocysteine level and the lowest mean C-IMT among others. Conclusions This study supports that the MTHFR 677T allele polymorphism is not associated with hyperhomocysteinemia as well as an increase in C-IMT in post ischemic stroke patients. PMID:26734634

  6. Seven novel mutations at the 5,10-methylenetetrahydrofolate reductase locus

    SciTech Connect

    Goyette, P.; Frosst, P.; Rosenblatt, D.S.; Rozen, R.

    1994-09-01

    5,10-methylenetetrahydrofolate reductase (MTHFR), a flavoprotein, catalyzes the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, a cofactor for methionine synthase in the methylation of homocysteine to methionine. Severe MTHFR deficiency, which causes homocysteinemia, is an autosomal recessive disorder with variable clinical features; developmental delay, perinatal death, mental retardation and asymptomatic individuals have been observed. A milder deficiency has been reported in patients with cardiovascular disease. We have recently described the isolation of a cDNA for MTHFR and the identification of 2 mutations in patients with severe MTHFR deficiency. We report here the characterization of 7 additional mutations at this locus: 5 missense mutations and 2 splicing mutations. Mutation analysis was performed by SSCP on PCR products generated either from reverse transcription-PCR of patients` total fibroblast RNA or from PCR of patients` genomic DNA. The 5 missense mutations are as follows: 1 Arg to Cys substitution in a hydrophilic segment proposed to be the hinge region that connects the catalytic and regulatory domains, 2 different Arg to Cys substitutions in 2 patients whose enzymatic thermolability is responsive to FAD, 1 Thr to Met substitution affecting an evolutionarily-conserved residue and a Pro to Leu substitution. The 2 splicing mutations affect the 5{prime} splice site and the 3{prime} splice site of 2 introns, respectively. The 5{prime} splice site mutation generates a 57 bp in-frame deletion of the RNA through the utilization of a cryptic 5{prime} splice site within the coding sequence. The identification of 9 mutations at this locus has allowed us to make preliminary correlations between genotype and phenotype and to contribute to a structure:function analysis of the enzyme.

  7. Adaptive developmental plasticity in methylene tetrahydrofolate reductase (MTHFR) C677T polymorphism limits its frequency in South Indians.

    PubMed

    Naushad, Shaik Mohammad; Krishnaprasad, Chintakindi; Devi, Akella Radha Rama

    2014-05-01

    Methylene tetrahydrofolate reductase (MTHFR) C677T polymorphism shows considerable heterogeneity in its distribution in humans worldwide. The current study was conducted to investigate whether this polymorphism exhibited adaptive developmental plasticity in the control of the TT-genotype frequency. We screened 1,818 South Indian subjects (895 males and 923 females) for MTHFR C677T polymorphism using PCR-restriction fragment length polymorphism approach. MTHFR 677T-allele frequency in males and females was 9.1 and 11.0%, respectively. Compared to females, males had lower frequency of TT-genotype [odds ratio 0.31, 95% confidence interval (CI) 0.08-1.01]. The frequency of MTHFR 677T-allele was highest in the age group of 20-40 years and it gradually decreased from 40-60 to 60-80 years (P trend<0.0001). MTHFR 677TT-genotype was associated with 7.02-folds (95% CI: 2.12-25.63, P<0.0001) cumulative risk for recurrent pregnancy loss (RPL), neural tube defects (NTDs) and deep vein thrombosis (DVT). Linear regression model suggested that male gender exhibited increased homocysteine levels by 9.35 ?mol/L while each MTHFR 677T-allele contributed to 4.63 ?mol/L increase in homocysteine. Plasma homocysteine showed inverse correlation with dietary folate (r=-0.17, P<0.0001), B2 (r=-0.14, P<0.0001) and B6 (r=-0.07, P=0.03). Examination of the spontaneously aborted fetuses (n=35) showed no significant association of fetal genotype on its in utero viability. From the current study, it was concluded that C677T seemed to have acquired adaptive developmental plasticity among South Indians due to environmental influences thus contributing to hyperhomocysteinemia and its associated complications such as RPL, NTDs, DVT, etc. PMID:24449370

  8. Association study of methylenetetrahydrofolate reductase A1298C mutation with cerebral venous thrombosis risk in an Iranian population

    PubMed Central

    Habib, Ghaznavi; Zahra, Soheili; Shahram, Samiei; Soltanpour, Mohammad Soleiman

    2015-01-01

    Background: Cerebral venous thrombosis (CVT) is an uncommon condition characterized by severe clinical manifestations and high mortality rate. There is limited data on the role of methylenetetrahydrofolate reductase (MTHFR) A1298C mutation as a risk factor for CVT development in Iranians. Aim: The aim was to investigate a possible association between fasting plasma homocysteine (Hcy) levels, MTHFR A1298C mutation, and CVT in Iranian population. Materials and Methods: The study population consisted of 50 patients with a diagnosis of CVT (20–63 years old) and 75 healthy subjects (18–65 years old) as control. Genotyping of the MTHFR A1298C mutation and Hcy measurement was carried out by polymerase chain reaction-restriction fragment length polymorphism technique and enzyme immunoassay method, respectively. Results: Fasting plasma total Hcy levels were significantly higher in CVT patients than controls (P = 0.015). No significant differences were observed in the MTHFR A1298C genotypes frequency between CVT patients and controls (P > 0.05). The frequency of the 1298C allele was 36% and 37.5% in CVT patients and controls, respectively and did not differ significantly between the two groups (P = 0.16). Conclusions: Our study demonstrated that MTHFR A1298Cmutation is not a significant risk factor for CVT. PMID:26539365

  9. Altered protein phosphatase 2A methylation and Tau phosphorylation in the young and aged brain of methylenetetrahydrofolate reductase (MTHFR) deficient mice.

    PubMed

    Sontag, Jean-Marie; Wasek, Brandi; Taleski, Goce; Smith, Josephine; Arning, Erland; Sontag, Estelle; Bottiglieri, Teodoro

    2014-01-01

    Common functional polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene, a key enzyme in folate and homocysteine metabolism, influence risk for a variety of complex disorders, including developmental, vascular, and neurological diseases. MTHFR deficiency is associated with elevation of homocysteine levels and alterations in the methylation cycle. Here, using young and aged Mthfr knockout mouse models, we show that mild MTHFR deficiency can lead to brain-region specific impairment of the methylation of Ser/Thr protein phosphatase 2A (PP2A). Relative to wild-type controls, decreased expression levels of PP2A and leucine carboxyl methyltransferase (LCMT1) were primarily observed in the hippocampus and cerebellum, and to a lesser extent in the cortex of young null Mthfr (-/-) and aged heterozygous Mthfr (+/-) mice. A marked down regulation of LCMT1 correlated with the loss of PP2A/Bα holoenzymes. Dietary folate deficiency significantly decreased LCMT1, methylated PP2A and PP2A/Bα levels in all brain regions examined from aged Mthfr (+/+) mice, and further exacerbated the regional effects of MTHFR deficiency in aged Mthfr (+/-) mice. In turn, the down regulation of PP2A/Bα was associated with enhanced phosphorylation of Tau, a neuropathological hallmark of Alzheimer's disease (AD). Our findings identify hypomethylation of PP2A enzymes, which are major CNS phosphatases, as a novel mechanism by which MTHFR deficiency and Mthfr gene-diet interactions could lead to disruption of neuronal homeostasis, and increase the risk for a variety of neuropsychiatric disorders, including age-related diseases like sporadic AD. PMID:25202269

  10. Cerebral venous sinus thrombosis presenting as transient ischemic attacks in a case with homozygous mutations of MTHFR A1298C and CG677T.

    PubMed

    Yildiz, Ozlem Kayim; Cevik, Seyda; Cil, Gulsum; Oztoprak, Ibrahim; Bolayir, Ertugrul; Topaktas, Suat

    2012-01-01

    We report a case with recurrent, transient attacks of slurred speech, weakness, and numbness of the right half of the face and the right arm without seizure activity, accompanied by headache and double vision. Neurologic examination revealed bilateral papilledema and right abducens palsy. Brain magnetic resonance imaging revealed thrombosis of the dural venous sinuses and the cortical veins, with no evidence of parenchymal lesion. Homozygous mutations were found for methylenetetrahydrofolate reductase (MTHFR) A1298C and MTHFR CG677T. Anticoagulation with heparin and warfarin resulted in prompt cessation of the transient attacks, as well as the signs and symptoms of increased intracranial pressure. This report documents that, although rare, transient ischemic attacks can result from cerebral venous thrombosis. PMID:20833086

  11. Altered protein phosphatase 2A methylation and Tau phosphorylation in the young and aged brain of methylenetetrahydrofolate reductase (MTHFR) deficient mice

    PubMed Central

    Sontag, Jean-Marie; Wasek, Brandi; Taleski, Goce; Smith, Josephine; Arning, Erland; Sontag, Estelle; Bottiglieri, Teodoro

    2014-01-01

    Common functional polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene, a key enzyme in folate and homocysteine metabolism, influence risk for a variety of complex disorders, including developmental, vascular, and neurological diseases. MTHFR deficiency is associated with elevation of homocysteine levels and alterations in the methylation cycle. Here, using young and aged Mthfr knockout mouse models, we show that mild MTHFR deficiency can lead to brain-region specific impairment of the methylation of Ser/Thr protein phosphatase 2A (PP2A). Relative to wild-type controls, decreased expression levels of PP2A and leucine carboxyl methyltransferase (LCMT1) were primarily observed in the hippocampus and cerebellum, and to a lesser extent in the cortex of young null Mthfr−/− and aged heterozygous Mthfr+/− mice. A marked down regulation of LCMT1 correlated with the loss of PP2A/Bα holoenzymes. Dietary folate deficiency significantly decreased LCMT1, methylated PP2A and PP2A/Bα levels in all brain regions examined from aged Mthfr+/+ mice, and further exacerbated the regional effects of MTHFR deficiency in aged Mthfr+/− mice. In turn, the down regulation of PP2A/Bα was associated with enhanced phosphorylation of Tau, a neuropathological hallmark of Alzheimer’s disease (AD). Our findings identify hypomethylation of PP2A enzymes, which are major CNS phosphatases, as a novel mechanism by which MTHFR deficiency and Mthfr gene-diet interactions could lead to disruption of neuronal homeostasis, and increase the risk for a variety of neuropsychiatric disorders, including age-related diseases like sporadic AD. PMID:25202269

  12. Analysis of the 677 C-->T mutation of the methylenetetrahydrofolate reductase gene in different ethnic groups.

    PubMed

    Franco, R F; Araújo, A G; Guerreiro, J F; Elion, J; Zago, M A

    1998-01-01

    A recently described mutation in the methylenetetrahydrofolate reductase (MTHFR) gene (a C to T transition at nucleotide 677) is associated with a thermolabile phenotype and decreased enzyme activity. In homozygotes, the mutation is also related to hyperhomocysteinemia and increased risk for atherosclerotic disease and (apparently) venous thrombosis. The prevalence of this mutation in different human populations is unknown. We have investigated the frequency of the 677 C-->T mutation in the MTHFR gene in 337 individuals (674 chromosomes) belonging to four ethnic groups: Whites, African and Brazilian Blacks, Asians and Amerindians. The frequencies of the positive allele among Whites and Asians were similar to those previously reported for Caucasian populations. The positive allele seems to be slightly rarer among the Amerindians (frequency 24.0%) in comparison to Whites and Asians, with a heterogeneous distribution among the five Indian tribes analysed. In contrast, the mutation has a very low prevalence in Blacks, especially among the African Blacks, for whom the mutation was absent in homozygosity. Our data indicate that the 677 C-->T MTHFR mutation has a significantly heterogeneous distribution among different ethnic groups, a fact that may contribute to explain geographical or racial differences in the risk for vascular disease. PMID:9459335

  13. Association of methylenetetrahydrofolate reductase (MTHFR) gene polymorphism with ischemic stroke in the Eastern Chinese Han population.

    PubMed

    Lv, Q-Q; Lu, J; Sun, H; Zhang, J-S

    2015-01-01

    The association between the MTHFR genetic polymorphism and ischemic stroke has been reported by a number of investigators. However, the results have been controversial and conflicting. The aim of this study was to explore the association between the MTHFR variants C677T and A1298C and the risk of ischemic stroke in an Eastern Chinese Han population. A total of 199 patients with ischemic stroke and 241 controls were recruited. Genotyping of the MTHFR C677T and A1298C polymorphisms was carried out using the Taqman 7900HT Sequence Detection System. The overall estimates (odds ratio: OR) for the allele (C) and genotype (AC+CC) of the A1298C polymorphism were 1.57 [95% confidence interval (CI) = 1.16-2.10], and 2.36 (95%CI = 1.39-4.00), respectively, establishing significant association of the MTHFR A1298C polymorphism with ischemic stroke. In contrast, there were no statistically significant differences compared to controls between MTHFR C677T polymorphic variants in the association ischemic stroke risk. Furthermore, haplotype-based analysis demonstrated that compared with the C-677-A-1298 haplotype, the C-677-C-1298 and T-677-C-1298 haplotypes showed significant increased risk of ischemic stroke (OR = 1.56; 95%CI = 1.07- 2.2; P = 0.02; OR = 1.76; 95%CI = 1.17-2.65; P < 0.01, respectively). We concluded that the A1298C polymorphism and the haplotypes C-677-C-1298 and T-677-C-1298 in MTHFR might modulate the risk of ischemic stroke in the Eastern Chinese Han population. PMID:25966188

  14. Distribution of alleles of the methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism in familial spina bifida.

    PubMed

    Johnson, W G; Stenroos, E S; Heath, S C; Chen, Y; Carroll, R; McKoy, V V; Chatkupt, S; Lehner, T

    1999-12-22

    Spina bifida cystica (SB) is one of the most common and disabling of birth defects. Folic acid supplementation in mothers during the periconceptional period has been shown to prevent more than 70% of neural tube defects (NTD) including SB. However, the mechanism is unknown. We tested a series of multicase SB families in which 224 individuals were genotyped and a group of 215 unrelated unaffected (external) control individuals for association of SB with the T allele of methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism that produces a heat-labile enzyme protein. The data were analyzed using first the transmission/disequilibrium test (TDT) and second a modified case-control study design with Monte Carlo sampling methods. No association of SB with the MTHFR T allele was found by either method. Presently, association between SB and the T allele has been found in four studies, a Dutch study, an Irish study, a North American study, and an Italian study. But no association was found in four other studies, a British study, a French study, a Turkish study, and a German study. A California population-based study found only modestly increased risk of SB with this allele that was not significant at the P < 0.05 level. The present study finds no evidence of the association. Only one other study, the German study, has used TDT analysis. The present study is the first to use a modified case-control study design with Monte Carlo sampling methods to test this association. Thus, it appears that the MTHFR T allele is a risk factor for SB in some populations but not others. Major genetic risk factors for folate-related SB remain to be found. PMID:10594879

  15. High prevalence of hyperhomocysteinemia in chronic alcoholism: the importance of the thermolabile form of the enzyme methylenetetrahydrofolate reductase (MTHFR).

    PubMed

    de la Vega, M J; Santolaria, F; Gonzlez-Reimers, E; Alemn, M R; Milena, A; Martnez-Riera, A; Gonzlez-Garca, C

    2001-10-01

    Alcoholism is related to malnutrition and low levels of several vitamins that take part in the metabolism of homocysteine. The objective of the study was to analyze the prevalence of hyperhomocysteinemia in patients with heavy alcohol intake and the factors on which it depends. Included in the study were 103 hospitalized heavy drinkers (i.e., patients with an intake of alcohol greater than 80 g per day). Serum homocysteine, folate, and vitamin B(12) levels, plasma vitamin B(6) levels, and CT677 polymorphisms of methylenetetrahydrofolate reductase (MTHFR) were determined. We also recorded the intensity of alcoholism, the status of nutrition, and the existence of liver cirrhosis. Determination of biochemical data was repeated after 15 days of withdrawal. Serum homocysteine levels were found to be significantly elevated, whereas serum folate and plasma B(6) levels were significantly decreased. Serum homocysteine levels were significantly higher in those heavy drinkers who showed the TT polymorphism of MTHFR, with a prevalence of hyperhomocysteinemia of 84.2% in the homozygote TT, 54.3% in the heterozygote CT, and 31.6% in the normal CC genotype. Serum homocysteine inversely correlated with serum folate, serum B(12), and plasma B(6) levels. We did not find any relation between serum homocysteine and intensity of alcoholism, nutritional status, or liver cirrhosis. Serum folate levels were significantly decreased in heavy drinkers, mainly depending on irregular feeding and malnutrition. After 15 days of withdrawal, serum homocysteine levels significantly decreased, whereas folate, B(12), and B(6) levels significantly increased. The conclusion is that heavy drinkers show a high prevalence of hyperhomocysteinemia related to low levels of folate, B(6), and B(12) and to the TT polymorphism of MTHFR. PMID:11747974

  16. Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and high plasma homocysteine in chronic hepatitis C (CHC) infected patients from the Northeast of Brazil

    PubMed Central

    2011-01-01

    Background/Aim Hyperhomocysteinemia due to Methylenetetrahydrofolate Reductase (MTHFR) gene, in particular the C677T (Ala222Val) polymorphism were recently associated to steatosis and fibrosis. We analyzed the frequency of MTHFR gene in a cross-sectional study of patients affected by Chronic Hepatitis C (CHC) from Northeast of Brazil. Method One hundred seven-four untreated patients with CHC were genotyped for the C677T MTHFR. Genomic DNA was extracted from peripheral blood cells and the C677T MTHFR polymorphism was identified by PCR-RFLP. The homocysteine (Hcy) levels were determined by chemiluminescence method. All patients were negative for markers of Wilson's disease, hemochromatosis and autoimmune diseases and have current and past daily alcohol intake less than 100 g/week. Results Among subjects infected with CHC genotype non-1 the frequency of MTHFR genotypes TT was 9.8% versus 4.4% genotype 1 (p = 0.01). Nevertheless, association was found between the MTHFR genotype TT CT/CC polymorphism and the degree of steatosis and fibrosis in both hepatitis C genotype (p < 0.05). A significant difference was found on plasma Hcy levels in patients with steatosis regardless of HCV genotype (p = 0.03). Conclusion Our results indicate that plasma Hcy levels is highly prevalent in subjects with chronic hepatits C with steatosis regardless of HCV genotype and vitamin deficiency. The presence of genotype TT of MTHFR C677T polymorphism was more common in CHC genotype non-1 infected patient regardless of histopathological classification and genotype TT+CT frequencies were significant in the presence of fibrosis grade 1+2 and of steatosis in CHC infected patients from the northeast of Brazil regardless of HCV genotype. The genetic susceptibility of MTHFR C677T polymorphism should be confirmed in a large population. PMID:21854603

  17. MTHFR 677C/T and 1298A/C mutations and non-alcoholic fatty liver disease.

    PubMed

    Kasapoglu, Benan; Turkay, Cansel; Yalcin, Kadir Serkan; Kosar, Ali; Bozkurt, Alper

    2015-06-01

    Common genetic mutations encountered in folate metabolism may result in increased homocysteine (Hcy) levels. It has been reported that increased serum Hcy levels may affect the intracellular fat metabolism and may cause enhanced fatty infiltration in the liver resulting in non-alcoholic fatty liver disease (NAFLD). In total, 150 patients diagnosed with FLD by ultrasound examination and 136 healthy control patients that do not have any fatty infiltration in the liver were included in the study. Patients were grouped as mild (n = 88), moderate (n = 38) or severe (n = 24) according to the stage of fatty liver in ultrasound. Serum liver function tests, Hcy, folic acid and vitamin B12 levels of the patients were studied. The genetic MTHFR C677T and A1298C polymorphisms of the patients were also evaluated. Although there was no significant difference in vitamin B12 and folic acid levels, in the severe group, Hcy levels were significantly higher than that of control and mild groups (p<0.001). By contrast, there was no significant difference in heterozygote MTHFR 677C/T and 1298A/C mutations, both MTHFR 677C/T and MTHFR 1298A/C mutations were more common in NAFLD groups compared with the control patients (p<0.001). We have determined increased Hcy levels and increased prevalence of homozygote MTHFR 677C/T and MTHFR 1298A/C mutations in patients with NAFLD compared with healthy controls. Larger studies are warranted to clarify the etiological role of the MTHFR mutations and Hcy levels in FLD. PMID:26031974

  18. Molecular genetic analysis in mild hyperhomocysteinemia: A common mutation in the methylenetetrahydrofolate reductase gene is a genetic risk factor for cardiovascular disease

    SciTech Connect

    Kluijtmans, L.A.J.; Heuvel, L.P.W.J. van den; Stevens, E.M.B.

    1996-01-01

    Mild hyperhomocysteinemia is an established risk factor for cardiovascular disease. Genetic aberrations in the cystathionine P-synthase (CBS) and methylenetetrahydrofolate reductase (MTHFR) genes may account for reduced enzyme activities and elevated plasma homocysteine levels. In 15 unrelated Dutch patients with homozygous CBS deficiency, we observed the 833T{yields}C (1278T) mutation in 50% of the alleles. Very recently, we identified a common mutation (677C{yields}T; A{yields}V) in the MTHFR gene, which, in homozygous state, is responsible for the thermolabile phenotype and which is associated with decreased specific MTHFR activity and elevated homocysteine levels. We screened 60 cardiovascular patients and 111 controls for these two mutations, to determine whether these mutations are risk factors for premature cardiovascular disease. Heterozygosity for the 833T{yields}C mutation in the CBS gene was observed in one individual of the control group but was absent in patients with premature cardiovascular disease. Homozygosity for the 677C-{yields}T mutation in the MTHFR gene was found in 9 (15%) of 60 cardiovascular patients and in only 6 ({approximately}5%) of 111 control individuals (odds ratio 3.1 [95% confidence interval 1.0-9.21]). Because of both the high prevalence of the 833T-{yields}C mutation among homozygotes for CBS deficiency and its absence in 60 cardiovascular patients, we may conclude that heterozygosity for CBS deficiency does not appear to be involved in premature cardiovascular disease. However, a frequent homozygous mutation in the MTHFR gene is associated with a threefold increase in risk for premature cardiovascular disease. 35 refs., 3 figs., 1 tab.

  19. Association of PHB 1630 C>T and MTHFR 677 C>T polymorphisms with breast and ovarian cancer risk in BRCA1/2 mutation carriers: results from a multicenter study

    PubMed Central

    Jakubowska, A; Rozkrut, D; Antoniou, A; Hamann, U; Scott, R J; McGuffog, L; Healy, S; Sinilnikova, O M; Rennert, G; Lejbkowicz, F; Flugelman, A; Andrulis, I L; Glendon, G; Ozcelik, H; Thomassen, M; Paligo, M; Aretini, P; Kantala, J; Aroer, B; von Wachenfeldt, A; Liljegren, A; Loman, N; Herbst, K; Kristoffersson, U; Rosenquist, R; Karlsson, P; Stenmark-Askmalm, M; Melin, B; Nathanson, K L; Domchek, S M; Byrski, T; Huzarski, T; Gronwald, J; Menkiszak, J; Cybulski, C; Serrano, P; Osorio, A; Cajal, T R; Tsitlaidou, M; Benítez, J; Gilbert, M; Rookus, M; Aalfs, C M; Kluijt, I; Boessenkool-Pape, J L; Meijers-Heijboer, H E J; Oosterwijk, J C; van Asperen, C J; Blok, M J; Nelen, M R; van den Ouweland, A M W; Seynaeve, C; van der Luijt, R B; Devilee, P; Easton, D F; Peock, S; Frost, D; Platte, R; Ellis, S D; Fineberg, E; Evans, D G; Lalloo, F; Eeles, R; Jacobs, C; Adlard, J; Davidson, R; Eccles, D; Cole, T; Cook, J; Godwin, A; Bove, B; Stoppa-Lyonnet, D; Caux-Moncoutier, V; Belotti, M; Tirapo, C; Mazoyer, S; Barjhoux, L; Boutry-Kryza, N; Pujol, P; Coupier, I; Peyrat, J-P; Vennin, P; Muller, D; Fricker, J-P; Venat-Bouvet, L; Johannsson, O Th; Isaacs, C; Schmutzler, R; Wappenschmidt, B; Meindl, A; Arnold, N; Varon-Mateeva, R; Niederacher, D; Sutter, C; Deissler, H; Preisler-Adams, S; Simard, J; Soucy, P; Durocher, F; Chenevix-Trench, G; Beesley, J; Chen, X; Rebbeck, T; Couch, F; Wang, X; Lindor, N; Fredericksen, Z; Pankratz, V S; Peterlongo, P; Bonanni, B; Fortuzzi, S; Peissel, B; Szabo, C; Mai, P L; Loud, J T; Lubinski, J

    2012-01-01

    Background: The variable penetrance of breast cancer in BRCA1/2 mutation carriers suggests that other genetic or environmental factors modify breast cancer risk. Two genes of special interest are prohibitin (PHB) and methylene-tetrahydrofolate reductase (MTHFR), both of which are important either directly or indirectly in maintaining genomic integrity. Methods: To evaluate the potential role of genetic variants within PHB and MTHFR in breast and ovarian cancer risk, 4102 BRCA1 and 2093 BRCA2 mutation carriers, and 6211 BRCA1 and 2902 BRCA2 carriers from the Consortium of Investigators of Modifiers of BRCA1 and BRCA2 (CIMBA) were genotyped for the PHB 1630 C>T (rs6917) polymorphism and the MTHFR 677 C>T (rs1801133) polymorphism, respectively. Results: There was no evidence of association between the PHB 1630 C>T and MTHFR 677 C>T polymorphisms with either disease for BRCA1 or BRCA2 mutation carriers when breast and ovarian cancer associations were evaluated separately. Analysis that evaluated associations for breast and ovarian cancer simultaneously showed some evidence that BRCA1 mutation carriers who had the rare homozygote genotype (TT) of the PHB 1630 C>T polymorphism were at increased risk of both breast and ovarian cancer (HR 1.50, 95%CI 1.10–2.04 and HR 2.16, 95%CI 1.24–3.76, respectively). However, there was no evidence of association under a multiplicative model for the effect of each minor allele. Conclusion: The PHB 1630TT genotype may modify breast and ovarian cancer risks in BRCA1 mutation carriers. This association need to be evaluated in larger series of BRCA1 mutation carriers. PMID:22669161

  20. Prevalence of factor V Leiden, prothrombin G20210A, and MTHFR C677T mutations in 200 healthy Jordanians.

    PubMed

    Eid, Suhair S; Rihani, Ghada

    2004-01-01

    Thrombophilia is now considered a multi-causal condition, with interplay of acquired genetic risk factors. In order to estimate the frequency of the factor V Leiden, prothrombin G20210A, and MTHFR C677T mutations in the Jordanian population, we screened 200 healthy Jordanian individuals. 40% were females. Mean age was 32.1 years for males and 30.0 years for female participants. A PCR method detected 15.0% factor V Leiden (87% heterozygous, 13% homozygous), 2% prothrombin G20210A (100% heterozygous), and 24% MTHFR C677T (67% heterozygous, 33% homozygous). We conclude that the prevalence of factor V Leiden and MTHFR C677T is elevated in this population of Jordanians. However the incidence of G20210A is relatively low. Quantification of these genetic thrombosis risk factors in various populations will contribute to a better understanding of the interaction of genetic and environmental risk factors. PMID:15559724

  1. Meta-analysis of Methylenetetrahydrofolate reductase maternal gene in Down syndrome: increased susceptibility in women carriers of the MTHFR 677T allele.

    PubMed

    Victorino, D B; Godoy, M F; Goloni-Bertollo, E M; Pavarino, E C

    2014-08-01

    Because a number of data studies include some controversial results about Methylenetetrahydrofolate reductase (MTHFR) polymorphisms and Down syndrome (DS), we performed a meta-analysis to determine a more precise estimation of this association. Studies were searched on PubMed, EMBASE and Lilacs-Scielo, up to April 2013, and they were eligible if they included case mothers (DSM) that have gave birth to children with DS, and controls mothers (CM) that have gave birth to healthy children without chromosomal abnormality, syndrome or malformation. The combined odds ratio with 95% confidence intervals was calculated by fixed or random effects models to assess the strength of associations. Potential sources of heterogeneity between studies were evaluated using Q test and the I(2). Publication bias was estimated using Begg's test and Egger's linear regression test. Sensitivity analyses were performed by using allelic, dominant, recessive and codominant genetic models, Hardy-Weinberg equilibrium (HWE) and ethnicity. Twenty-two studies with 2,223 DSM and 2,807 CM were included for MTHFR C677T and 15 studies with 1,601 DSM and 1,849 CM were included for MTHFR A1298C. Overall analysis suggests an association of the MTHFR C677T polymorphism with maternal risk for DS. Moreover, no association between the MTHFR A1298C polymorphism and maternal risk for DS was found. There is also evidence of higher heterogeneity, with I(2) test values ranging from 8 to 89%. No evidence of publication bias was found. Taken together, our meta-analysis implied that the T allele carriers might carry an increased maternal risk for DS. PMID:24913031

  2. Combination of factor V Leiden and MTHFR mutations in myocardial infarction.

    PubMed

    Fekih-Mrissa, Najiba; Berredjeb-Benslama, Dhouha; Haggui, Abdeddayem; Haouala, Habib; Gritli, Nasreddine

    2013-01-01

    Identifying patients who are at high risk of suffering myocardial infarction can be done by determining risk factors or by the adoption of molecular genetic testing for inherited thrombophilia. We report a case of myocardial infarction at a young age. The patient complained of dyspnea (stage III) and a burning pain of severe intensity that radiated to the left retrosternal side, but was not associated with palpitations or diaphoresis. A number of biochemical parameters were normal except for an elevated creatinine phosphokinase (CPK) level. Genetic testing revealed the subject to be heterozygous for both the factor V leiden and MTHFR C677T polymorphisms. The combination of these two mutations may be a high risk factor for myocardial infarction. Genetic screening for inherited thrombophilia in young patients, especially in the presence of a common risk factor, may be useful for primary thrombopro.phylaxis and in asymptomatic relatives of patients. PMID:22750768

  3. A COMMON POLYMORPHISM IN THE METHYLENETETRAHYDROFOLATE REDUCTASE (MTHFR) GENE IS ASSOCIATED WITH QUANTITATIVE ULTRASOUND IN THOSE WITH LOW PLASMA FOLATE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study of a polymorphism in the MTHFR gene, plasma folate, and bone phenotypes in 1632 individuals revealed that the genotype effect on BMD and quantitative ultrasound was dependent on the level of folate. Our findings support the hypothesis that the association between an MTHFR polymorphism and bo...

  4. Methylenetetrahydrofolate reductase (MTHFR) genetic variation and major depressive disorder prognosis: A five-year prospective cohort study of primary care attendees.

    PubMed

    Bousman, Chad A; Potiriadis, Maria; Everall, Ian P; Gunn, Jane M

    2014-01-01

    Methylenetetrahydrofolate reductase (MTHFR) genetic variation has been associated with the diagnosis of major depressive disorder (MDD) but no study to date has examined the effect MTHFR variation has on MDD prognosis. We sought to examine the prospective effects of two common MTHFR variants (C677T and A1298C) as well as seven haplotype-tagging single nucleotide polymorphisms (htSNPs) on MDD prognosis over a 5-year (60-month) period. Participants were 147 depressed primary care attendees enrolled in the Diagnosis, Management and Outcomes of Depression in Primary Care (diamond) prospective cohort study. Prognosis of MDD was measured using three methods: (1) DSM-IV criteria, (2) Primary Care Evaluation of Mental Disorders Patient Health Questionnaire-9 (PHQ-9), and (3) Center for Epidemiologic Studies Depression Scale (CESD). DSM-IV criteria for MDD was assessed using the Composite International Diagnostic Interview at baseline and 24, 36, 48, and 60 months post-baseline; whereas, PHQ-9 and CESD measures were employed at baseline and 12, 24, 36, 48, and 60 months post-baseline. Repeated measures analysis of variance showed that PHQ-9 symptom severity trajectories differed by C677T genotype (F?=?3.34, df?=?2,144, P?=?0.038), with 677CC genotype showing the most severe symptom severity course over the 60 months of observation. Neither the A1298C polymorphism nor any of the htSNPs were associated with MDD prognosis regardless of measure used. Our results suggest that the MTHFR C677T polymorphism may serve as a marker for MDD prognosis pending independent replication. PMID:24123968

  5. Elevated total plasma homocysteine and 667C{r_arrow}T mutation of the 5,10-methylenetetrahydrofolate reductase gene in thrombotic vascular disease

    SciTech Connect

    De Franchis, R.; Sebastio, G.; Andria, G.

    1996-07-01

    Moderate elevation of total plasma homocysteine (tHcy) has been reported as an independent risk factor for thrombotic vascular disease, a well-known multifactorial disorder. Possible genetic causes of elevated tHcy include defects of the sulfur-containing amino acids metabolism due to deficiencies of cystathionine {Beta}-synthase, of 5,10-methylenetetrahydrofolate reductase (MTHFR), and of the enzymes of cobalamin metabolism. An impaired activity of MTHFR due to a thermolabile form of the enzyme has been observed in {le}28% of hyperhomocysteinemic patients with premature vascular disease. More recently, the molecular basis of such enzymatic thermolability has been related to a common mutation of the MTHFR gene, causing a C-to-T substitution at nt 677 (677C{r_arrow}T). This mutation was found in 38% of unselected chromosomes from 57 French Canadian individuals. The homozygous state for the mutation was present in 12% of these subjects and correlated with significantly elevated tHcy. Preliminary evidence indicates that the frequency of homozygotes for the 677C{r_arrow}T mutation may vary significantly in populations from different geographic areas. 5 refs., 2 tabs.

  6. Insights on the structural perturbations in human MTHFR Ala222Val mutant by protein modeling and molecular dynamics.

    PubMed

    Abhinand, P A; Shaikh, Faraz; Bhakat, Soumendranath; Radadiya, Ashish; Bhaskar, L V K S; Shah, Anamik; Ragunath, P K

    2016-04-01

    Methylenetetrahydrofolate reductase (MTHFR) protein catalyzes the only biochemical reaction which produces methyltetrahydrofolate, the active form of folic acid essential for several molecular functions. The Ala222Val polymorphism of human MTHFR encodes a thermolabile protein associated with increased risk of neural tube defects and cardiovascular disease. Experimental studies have shown that the mutation does not affect the kinetic properties of MTHFR, but inactivates the protein by increasing flavin adenine dinucleotide (FAD) loss. The lack of completely solved crystal structure of MTHFR is an impediment in understanding the structural perturbations caused by the Ala222Val mutation; computational modeling provides a suitable alternative. The three-dimensional structure of human MTHFR protein was obtained through homology modeling, by taking the MTHFR structures from Escherichia coli and Thermus thermophilus as templates. Subsequently, the modeled structure was docked with FAD using Glide, which revealed a very good binding affinity, authenticated by a Glide XP score of -10.3983 (kcal mol(-1)). The MTHFR was mutated by changing Alanine 222 to Valine. The wild-type MTHFR-FAD complex and the Ala222Val mutant MTHFR-FAD complex were subjected to molecular dynamics simulation over 50 ns period. The average difference in backbone root mean square deviation (RMSD) between wild and mutant variant was found to be ~.11 Å. The greater degree of fluctuations in the mutant protein translates to increased conformational stability as a result of mutation. The FAD-binding ability of the mutant MTHFR was also found to be significantly lowered as a result of decreased protein grip caused by increased conformational flexibility. The study provides insights into the Ala222Val mutation of human MTHFR that induces major conformational changes in the tertiary structure, causing a significant reduction in the FAD-binding affinity. PMID:26273990

  7. Hyperbaric Oxygen Therapy in Branch Retinal Artery Occlusion in a 15-Year-Old Boy with Methylenetetrahydrofolate Reductase Mutation

    PubMed Central

    Kadayifcilar, Sibel; Eldem, Bora

    2015-01-01

    Purpose. To report the efficacy of hyperbaric oxygen (HBO) therapy in a case of branch retinal artery occlusion (BRAO) in a 15-year-old boy. Methods. We report a 15-year-old boy with sudden loss of vision due to BRAO. Examination included laboratory evaluation for systemic risk factors. Follow-up exams included visual acuity, fundus examination, fundus fluorescein angiography, and visual field testing. HBO therapy was employed for treatment. Results. Medical history was positive for isolated glucocorticoid deficiency. Laboratory evaluation disclosed hyperhomocysteinemia and methylenetetrahydrofolate reductase (MTHFR) mutation. The visual acuity 0.05 at presentation improved to 0.8 after 20 days of HBO therapy. There was no change on visual fields. Conclusion. In this pediatric case, HBO therapy was useful in the treatment of BRAO. PMID:25722905

  8. Mthfr as a modifier of the retinal phenotype of Crb1(rd8/rd8) mice.

    PubMed

    Markand, Shanu; Saul, Alan; Tawfik, Amany; Cui, Xuezhi; Rozen, Rima; Smith, Sylvia B

    2016-04-01

    Mutations in crumb homologue 1 (CRB1) in humans are associated with Leber's congenital amaurosis (LCA) and retinitis pigmentosa (RP). There is no clear genotype-phenotype correlation for human CRB1 mutations in RP and LCA. The high variability in clinical features observed in CRB1 mutations suggests that environmental factors or genetic modifiers influence severity of CRB1 related retinopathies. Retinal degeneration 8 (rd8) is a spontaneous mutation in the Crb1 gene (Crb1(rdr/rd8)). Crb1(rdr/rd8) mice present with focal disruption in the outer retina manifesting as white spots on fundus examination. Mild retinal dysfunction with decreased b-wave amplitude has been reported in Crb1(rdr/rd8) mice at 18 months. Methylene tetrahydrofolate reductase (MTHFR) is a crucial enzyme of homocysteine metabolism. MTHFR mutations are prevalent in humans and are linked to a broad spectrum of disorders including cardiovascular and neurodegenerative diseases. We recently reported the retinal phenotype in Mthfr-deficient (Mthfr(+/-)) heterozygous mice. At 24 weeks the mice showed decreased RGC function, thinner nerve fiber layer, focal areas of vascular leakage and 20% fewer cells in the ganglion cell layer (GCL). Considering the variability in CRB1-related retinopathies and the high occurrence of human MTHFR mutations we evaluated whether Mthfr deficiency influences rd8 retinal phenotype. Mthfr heterozygous mice with rd8 mutations (Mthfr(+/-)(rd8/rd8)) and Crb(rd8/rd8) mice (Mthfr(+/+rd8/rd8)) mice were subjected to comprehensive retinal evaluation using ERG, fundoscopy, fluorescein angiography (FA), morphometric and retinal flat mount immunostaining analyses of isolectin-B4 at 8-54 wks. Assessment of retinal function revealed a significant decrease in the a-, b- and c-wave amplitudes in Mthfr(+/-)(rd8/rd8) mice at 52 wks. Fundoscopic evaluation demonstrated the presence of signature rd8 spots in Mthfr(+/+rd8/rd8) mice and an increase in the extent of these rd8 spots in Mthfr(+/-)(rd8/rd8) mice at 24 weeks and beyond. FA revealed marked vascular leakage, ischemia and vascular tortuosity in Mthfr(+/-)(rd8/rd8) mice at 24 and 52 weeks. Retinal dysplasia was observed in ∼14-33% Mthfr(+/-)(rd8/rd8) mice by morphometric analysis. This was accompanied by a ∼20% reduction in cells of the GCL of Mthfr(+/-)(rd8/rd8) mice at 24 and 52 weeks. Retinal flat mount immunostaining with isolectin-B4 showed neovascularization and loss of blood vessel integrity in Mthfr(+/-)(rd8/rd8) mice in contrast to mild vasculopathy in Mthfr(+/+rd8/rd8) mice. Taken together, our data support an earlier onset and worsened retinal phenotype when Mthfr and rd8 mutations coexist. Our study sets the stage for future studies to investigate the role of MTHFR deficiency in human CRB1 retinopathies. PMID:26646559

  9. MTHFR (C677T) polymorphism and PR (PROGINS) mutation as genetic factors for preterm delivery, fetal death and low birth weight: A Northeast Indian population based study

    PubMed Central

    Tiwari, Diptika; Bose, Purabi Deka; Das, Somdatta; Das, Chandana Ray; Datta, Ratul; Bose, Sujoy

    2015-01-01

    Preterm delivery (PTD) is one of the most significant contributors to neonatal mortality, morbidity, and long-term adverse consequences for health; with highest prevalence reported from India. The incidence of PTD is alarmingly very high in Northeast India. The objective of the present study is to evaluate the associative role of MTHFR gene polymorphism and progesterone receptor (PR) gene mutation (PROGINS) in susceptibility to PTD, negative pregnancy outcome and low birth weights (LBW) in Northeast Indian population. Methods A total of 209 PTD cases {extreme preterm (<28weeks of gestation, n=22), very preterm (2832weeks of gestation, n=43) and moderate preterm (3237weeks of gestation, n=144) and 194 term delivery cases were studied for MTHFR C677T polymorphism and PR (PROGINS) gene mutation. Statistical analysis was performed using SPSS software. Results Distribution of MTHFR and PR mutation was higher in PTD cases. Presence of MTHFR C677T polymorphism was significantly associated and resulted in the increased risk of PTD (p<0.001), negative pregnancy outcome (p<0.001) and LBW (p=0.001); more significantly in extreme and very preterm cases. Presence of PR mutation (PROGINS) also resulted in increased risk of PTD and negative pregnancy outcome; but importantly was found to increase the risk of LBW significantly in case of very preterm (p<0.001) and moderately preterm (p<0.001) delivery cases. Conclusions Both MTHFR C677T polymorphism and PR (PROGINS) mutation are evident genetic risk factors associated with the susceptibility of PTD, negative pregnancy outcome and LBW. MTHFR C677T may be used as a prognostic marker to stratify subpopulation of pregnancy cases predisposed to PTD; thereby controlling the risks associated with PTD. PMID:25709895

  10. Methylenetetrahydrofolate reductase (MTHFR) polymorphism (C677T) in relation to homocysteine concentration in overweight and obese Thais.

    PubMed

    Thawnashom, Kittisak; Tungtrongchitr, Rungsunn; Petmitr, Songsak; Pongpaew, Praneet; Phonrat, Benjaluck; Tungtrongchitr, Anchalee; Schelp, Frank Peter

    2005-03-01

    We analyzed the association between MTHFR (C677T) gene polymorphism with serum concentrations of homocysteine, folate, and vitamin B12 in 37 male and 112 female overweight/ obese Thai volunteers (BMI > or = 25.00 kg/m2), and compared them with 23 male and 90 female control subjects (BMI = 18.5-24.99 kg/m2). Statistically significant higher levels of serum homocysteine were found in the overweight/obese subjects than the control subjects (p < 0.05). Serum folic acid levels in the overweight/obese subjects were significantly lower than the control subjects (p < 0.05). When the data were grouped according to homocysteine concentration and MTHFR gene polymorphism, there were significantly higher homocysteine concentrations in the overweight/obese subjects than the control subjects in wild type gene polymorphism (CC) in the hyperhomocysteine group (homocysteine >10.0 mmol/l) (p < 0.05), but in genotype polymorphism (CC, CT, TT) there were lower folic acid and vitamin B12 concentrations in the overweight/obese subjects than in the control subjects. In the hyperhomocysteine groups, there was no significant difference in the frequencies of MTHFR (C677T) gene polymorphism between the overweight/obese subjects and the control subjects. Folic acid and gene polymorphism were found to be significantly related to the overweight/ obese and control groups in logistic regression analysis (p < 0.05). The results support the supposition that folic acid is more important than vitamin B12. PMID:15916056

  11. Brachial artery aneurysm accompanying a homozygous methylenetetrahydrofolate reductase mutation

    PubMed Central

    Guler, Adem; Tavlasoglu, Murat; Arslan, Zekeriya; Yesil, Fahri Gurkan

    2013-01-01

    Elevated plasma homocysteine (Hcy) is one of the suggested risk factors for endothelial dysfunction. There is evidence of association between raised plasma Hcy and an increased risk of developing peripheral arterial disease. A causal relationship, however, has not been established. In this report, a 37-year old male patient with the complaints of intermittent hand pain is presented. Brachial artery aneurysm accompanying a homozygous methylenetetrahydrofolate reductase mutation was detected. PMID:23460600

  12. Increased MTHFR promoter methylation in mothers of Down syndrome individuals.

    PubMed

    Coppedè, Fabio; Denaro, Maria; Tannorella, Pierpaola; Migliore, Lucia

    2016-05-01

    Despite that advanced maternal age at conception represents the major risk factor for the birth of a child with Down syndrome (DS), most of DS babies are born from women aging less than 35 years. Studies performed in peripheral lymphocytes of those women revealed several markers of global genome instability, including an increased frequency of micronuclei, shorter telomeres and impaired global DNA methylation. Furthermore, young mothers of DS individuals (MDS) are at increased risk to develop dementia later in life, suggesting that they might be "biologically older" than mothers of euploid babies of similar age. Mutations in folate pathway genes, and particularly in the methylenetetrahydrofolate reductase (MTHFR) one, have been often associated with maternal risk for a DS birth as well as with risk of dementia in the elderly. Recent studies pointed out that also changes in MTHFR methylation levels can contribute to human disease, but nothing is known about MTHFR methylation in MDS tissues. We investigated MTHFR promoter methylation in DNA extracted from perypheral lymphocytes of 40 MDS and 44 matched control women that coinceived their children before 35 years of age, observing a significantly increased MTHFR promoter methylation in the first group (33.3±8.1% vs. 28.3±5.8%; p=0.001). In addition, the frequency of micronucleated lymphocytes was available from the women included in the study, was higher in MDS than control mothers (16.1±8.6‰ vs. 10.5±4.3‰; p=0.0004), and correlated with MTHFR promoter methylation levels (r=0.33; p=0.006). Present data suggest that MTHFR epimutations are likely to contribute to the increased genomic instability observed in cells from MDS, and could play a role in the risk of birth of a child with DS as well as in the onset of age related diseases in those women. PMID:26926955

  13. Factor V Leiden, prothrombin 20210G-->A and the MTHFR C677T mutations in childhood stroke.

    PubMed

    McColl, M D; Chalmers, E A; Thomas, A; Sproul, A; Healey, C; Rafferty, I; McWilliam, R; Eunson, P

    1999-05-01

    Ischaemic stroke is a rare occurrence in children and in a proportion of cases the aetiology remains unknown. We have investigated the role of thrombophilia in the aetiology of this condition. Of 50 cases identified at two centres, 37 were available for detailed haematological analysis. No cases were identified with deficiencies of antithrombin, protein C or protein S. One case had elevated IgG anticardiolipin antibodies at low titre. The prevalence of the prothrombin 20210 G-->A mutation, factor V Leiden (FVL) mutation and the C677T mutation in the MTHFR gene was compared in cases to that observed in random unselected cord blood controls. The odds ratio for stroke was not significantly increased in carriers of the prothrombin mutation (OR 1.2; 95% CI 0.1-10.7), FVL (OR 2.5; 95% CI 0.5-13.5), or the C677T mutation (OR 1.7; 95% CI 0.6-4.5). Our findings suggest that thrombophilia may not play a significant role in the aetiology of stroke in children, although a large prospective study is required to investigate this area further. PMID:10365738

  14. Prevalence of MTHFR C677T single nucleotide polymorphism in genetically isolated populations in Jordan.

    PubMed

    Dajani, Rana; Fathallah, Raja; Arafat, Ala; AbdulQader, Mohammed Emad; Hakooz, Nancy; Al-Motassem, Yousef; El-Khateeb, Mohammad

    2013-10-01

    Methylenetetrahydrofolate reductase (MTHFR) C677T single nucleotide polymorphism is a major inherited risk factor of venous thromboembolism. We sought to determine its prevalence in genetically isolated populations of Chechens and Circassians in Jordan. The MTHFR C677T mutation was analyzed from blood samples taken from 120 random unrelated Chechens and 72 Circassians. The prevalence of the MTHFR mutation in the Chechen population was 27.5% (allele frequency 15%); the prevalence among the Circassians was 50% (allele frequency 29.2%). The prevalence in the Chechen population is similar to that in Jordan and other world populations, but it is higher in the Circassian population. This study will contribute to understanding the interaction between genetic and environmental risk factors underlying thrombosis and will be useful in deciding which genetic variants should be tested in a clinical genetic testing service. PMID:23749065

  15. Recurrent ischemic strokes in a young celiac woman with MTHFR gene mutation

    PubMed Central

    Fabbri, Elisa; Rustignoli, Lisa; Muscari, Antonio; Puddu, Giovanni M; Guarino, Maria; Rinaldi, Rita; Minguzzi, Elena; Caio, Giacomo; Zoli, Marco; Volta, Umberto

    2012-01-01

    Celiac disease (CD) is frequently associated with neurological disorders, but very few reports concern the association with ischemic stroke. A 26-year-old woman affected by CD with secondary amenorrhea, carrier of a homozygous 5,10-methylenetetrahydrofolate reductase mutation with hyperhomocysteinemia, was affected by two occipital ischemic strokes within a period of 5 mo. At the time of the second stroke, while she was being treated with folic acid, acetylsalicylic acid and a gluten-free diet, she had left hemianopsia, left hemiparesthesias, and gait imbalance. Brain magnetic resonance imaging showed a subacute right occipital ischemic lesion, which was extended to the dorsal region of the right thalamus and the ipsilateral thalamo-capsular junction. Antitransglutaminase and deamidated gliadin peptide antibodies were no longer present, while antinuclear antibodies, antineuronal antibodies and immune circulating complexes were only slightly elevated. Since the patient was taking folic acid, her homocysteine ??levels were almost normal and apparently not sufficient alone to explain the clinical event. A conventional cerebral angiography showed no signs of vasculitis. Finally, rare causes of occipital stroke in young patients, such as Fabrys disease and mitochondrial myopathy, encephalomyopathy, lactic acidosis and stroke-like symptoms, were also excluded by appropriate tests. Thus, the most probable cause for the recurrent strokes in this young woman remained CD, although the mechanisms involved are still unknown. The two main hypotheses concern malabsorption (with consequent deficiency of vitamins known to exert neurotrophic and neuroprotective effects) and immune-mediated mechanisms. CD should be kept in mind in the differential diagnosis of ischemic stroke in young patients. PMID:22807619

  16. [Relationship of MTHFR gene polymorphisms with infertility].

    PubMed

    Guo, Kai-min; Tian, Run-hui; Wang, Hong-liang

    2016-02-01

    The folate metabolic pathway plays important roles in cellular physiology by participating in nucleotide synthesis, DNA repair and methylation, and maintenance and stability of the genome. Methylenetetrahydrofolate reductase (MTHFR) is a key regulatory enzyme involved in folate metabolism. Polymorphisms of MTHFR may change the level of homocysteine and affect DNA synthesis and methylation, leading to an increased oxidative stress and disturbed methylation reactions and consequently affecting reproductive function. This article presents an overview on MTHFR gene polymorphisms, proposing that multicentered, large-sample and long-term prospective studies are needed to reveal the relationship between MTHFR gene polymorphisms and infertility. PMID:26939404

  17. Ethnic variation of the C677T and A1298C polymorphisms in the methylenetetrahydrofolate-reductase (MTHFR) gene in southwestern Mexico.

    PubMed

    Antonio-Véjar, V; Del Moral-Hernández, O; Alarcón-Romero, L C; Flores-Alfaro, E; Leyva-Vázquez, M A; Hernández-Sotelo, D; Illades-Aguiar, B

    2014-01-01

    In this study, we examined the distribution of genotype and allele frequencies of the C677T and A1298C polymorphisms in the methylenetetrahydrofolate-reductase gene (MTHFR) in two ethnic groups in the State of Guerrero, Mexico, which were compared with those of the Mestizo population of the region. A comparative study was conducted on 455 women from two ethnic groups and a group of Mestizo women of the State of Guerrero, Mexico: 135 Nahuas, 124 Mixtecas, and 196 Mestizas. Genotyping of both polymorphisms were performed by using polymerase chain reaction-restriction fragment length polymorphism methods. We found that the 677TT genotype was more frequent in Nahua and Mixteca women compared to Mestiza women (P = 0.008), and the most prevalent genotype in both ethnic groups was the 1298AA genotype (P < 0.001). We also compared the 677T allele frequency obtained from the groups studied with the frequencies reported in other ethnic groups of Mexico (Huichol, Tarahumara, and Purepecha). There were significant differences between the three ethnic groups compared to Nahuas (Huicholes, P = 0.004; Tarahumaras, P < 0.001; Purepechas, P = 0.042). Our results indicated significant differences in the frequencies of the C677T and A1298C polymorphisms between the two ethnic groups and the Mestizo population of the State of Guerrero. In addition, we found strong differences with other ethnic groups in Mexico. These results could be useful for future studies investigating diseases related to folate metabolism, and could help the government to design specific nutrition programs for different ethnic groups. PMID:25299110

  18. Massive pulmonary embolism associated with Factor V Leiden, prothrombin, and methylenetetrahydrofolate reductase gene mutations in a young patient on oral contraceptive pills: a case report.

    PubMed

    Charafeddine, Khalil M; Mahfouz, Rami A; Ibrahim, Georges Y; Taher, Ali T; Hoballah, Jamal J; Taha, Assad M

    2010-10-01

    Factor V Leiden (Factor V G1691A), prothrombin gene mutation G20210A, and homozygous C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene are known to predispose venous thromboembolism (VTE). We present herein a rare case of a young woman heterozygous for these mutations and taking oral contraceptive pills for less than 2 months, diagnosed to have massive deep venous thrombosis and bilateral pulmonary embolism. The patient was managed for 10 days in the hospital and discharged home on oral anticoagulants. This case suggests that screening for these factors in people with family history of thrombosis and in relatives of patients with these mutations is highly recommended to prevent fatal consequences. In addition, a new guideline for treatment and prophylaxis with anticoagulant for these patients and others who are at risk of developing VTE (American College of Chest Physicians [ACCP] guidelines-Chest 2008) has been published recently. Our recommendation is to promote for the internationally published algorithms through their application, where necessary, to prevent any future thrombotic morbidity or mortality incidents. PMID:19520679

  19. Smith-Lemli-Opitz syndrome is caused by mutations in the 7-dehydrocholesterol reductase gene.

    PubMed

    Waterham, H R; Wijburg, F A; Hennekam, R C; Vreken, P; Poll-The, B T; Dorland, L; Duran, M; Jira, P E; Smeitink, J A; Wevers, R A; Wanders, R J

    1998-08-01

    Smith-Lemli-Opitz syndrome is a frequently occurring autosomal recessive developmental disorder characterized by facial dysmorphisms, mental retardation, and multiple congenital anomalies. Biochemically, the disorder is caused by deficient activity of 7-dehydrocholesterol reductase, which catalyzes the final step in the cholesterol-biosynthesis pathway-that is, the reduction of the Delta7 double bond of 7-dehydrocholesterol to produce cholesterol. We identified a partial transcript coding for human 7-dehydrocholesterol reductase by searching the database of expressed sequence tags with the amino acid sequence for the Arabidopsis thaliana sterol Delta7-reductase and isolated the remaining 5' sequence by the "rapid amplification of cDNA ends" method, or 5'-RACE. The cDNA has an open reading frame of 1,425 bp coding for a polypeptide of 475 amino acids with a calculated molecular weight of 54.5 kD. Heterologous expression of the cDNA in the yeast Saccharomyces cerevisiae confirmed that it codes for 7-dehydrocholesterol reductase. Chromosomal mapping experiments localized the gene to chromosome 11q13. Sequence analysis of fibroblast 7-dehydrocholesterol reductase cDNA from three patients with Smith-Lemli-Opitz syndrome revealed distinct mutations, including a 134-bp insertion and three different point mutations, each of which was heterozygous in cDNA from the respective parents. Our data demonstrate that Smith-Lemli-Opitz syndrome is caused by mutations in the gene coding for 7-dehydrocholesterol reductase. PMID:9683613

  20. [Methylenetetrahydrofolate reductase deficiency-induced schizophrenia in a school-age boy].

    PubMed

    Wang, Qiao; Liu, Jing; Liu, Yu-Peng; Li, Xi-Yuan; Ma, Yan-Yan; Wu, Tong-Fei; Ding, Yuan; Song, Jin-Qing; Wang, Yu-Jie; Yang, Yan-Ling

    2014-01-01

    Methylenetetrahydrofolate reductase (MTHFR) deficiency is a rare autosomal recessive disorder. It is known that MTHFR deficiency may result in hyperhomocysteinemia, but MTHFR deficiency-induced schizophrenia has been rarely reported. Here we present the clinical course, biochemical and genetic characteristics of schizophrenia resulted from MTHFR deficiency in a school-age boy. He was 13 years old. He was admitted with a two-year history of fear, auditory hallucination, learning difficulty, sleeping problems, irascibility, drowsing and giggling. At admission, he had significantly elevated plasma and urine levels of total homocysteine, significantly decreased levels of folate in serum and cerebrospinal fluid, and a normal blood concentration of methionine. Further DNA sequencing analysis showed 665C>T homozygous mutations in the MTHFR gene. The patient was diagnosed with MTHFR deficiency-associated schizophrenia and treatment with calcium folinate, vitamin B12, vitamin B6, and betaine was initiated. After the treatment for 1 week, his plasma and urine levels of homocysteine were decreased to a normal range and the clinical symptoms were significantly improved. After 3 months of treatment, the patient returned to school. He is now living with normal school life. In summary, children with late-onset MTHFR deficiency and secondary cerebral folate deficiency may lead to schizophrenia. This rare condition can be early diagnosed through analyses of blood and urine total homocysteine, amino acids in blood and folate in blood and cerebral fluid and successfully treated with folinic acid, vitamin B6, vitamin B12 and betaine. PMID:24461181

  1. Homocysteine Metabolism Gene Polymorphisms (MTHFR C677T, MTHFR A1298C, MTR A2756G and MTRR A66G) Jointly Elevate the Risk of Folate Deficiency

    PubMed Central

    Li, Wen-Xing; Dai, Shao-Xing; Zheng, Jun-Juan; Liu, Jia-Qian; Huang, Jing-Fei

    2015-01-01

    Folate deficiency is strongly associated with cardiovascular disease. We aimed to explore the joint effect of the methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C, methionine synthase (MTR) A2756G, and methionine synthase reductase (MTRR) A66G polymorphisms on folate deficiency in a Chinese hypertensive population. A total of 480 subjects aged 28–75 were enrolled in this study from September 2005–December 2005 from six hospitals in different Chinese regions. Known genotypes were detected by PCR-RFLP methods and serum folate was measured by chemiluminescence immunoassay. Our results showed that MTHFR 677TT and MTR 2756AG + GG were independently associated with a higher risk of folate deficiency (TT vs. CC + CT, p < 0.001 and AG + GG vs. AA p = 0.030, respectively). However, the MTHFR A1298C mutation may confer protection by elevating the serum folate level (p = 0.025). Furthermore, patients carrying two or more risk genotypes showed higher odds of folate deficiency than null risk genotype carriers, especially those carrying four risk genotypes. These findings were verified by generalized multifactor dimensionality reduction (p = 0.0107) and a cumulative effects model (p = 0.001). The results of this study have shown that interactions among homocysteine metabolism gene polymorphisms lead to dramatic elevations in the folate deficiency risk. PMID:26266420

  2. Homocysteine Metabolism Gene Polymorphisms (MTHFR C677T, MTHFR A1298C, MTR A2756G and MTRR A66G) Jointly Elevate the Risk of Folate Deficiency.

    PubMed

    Li, Wen-Xing; Dai, Shao-Xing; Zheng, Jun-Juan; Liu, Jia-Qian; Huang, Jing-Fei

    2015-08-01

    Folate deficiency is strongly associated with cardiovascular disease. We aimed to explore the joint effect of the methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C, methionine synthase (MTR) A2756G, and methionine synthase reductase (MTRR) A66G polymorphisms on folate deficiency in a Chinese hypertensive population. A total of 480 subjects aged 28-75 were enrolled in this study from September 2005-December 2005 from six hospitals in different Chinese regions. Known genotypes were detected by PCR-RFLP methods and serum folate was measured by chemiluminescence immunoassay. Our results showed that MTHFR 677TT and MTR 2756AG + GG were independently associated with a higher risk of folate deficiency (TT vs. CC + CT, p < 0.001 and AG + GG vs. AA p = 0.030, respectively). However, the MTHFR A1298C mutation may confer protection by elevating the serum folate level (p = 0.025). Furthermore, patients carrying two or more risk genotypes showed higher odds of folate deficiency than null risk genotype carriers, especially those carrying four risk genotypes. These findings were verified by generalized multifactor dimensionality reduction (p = 0.0107) and a cumulative effects model (p = 0.001). The results of this study have shown that interactions among homocysteine metabolism gene polymorphisms lead to dramatic elevations in the folate deficiency risk. PMID:26266420

  3. MTHFR gene polymorphisms in bladder cancer in the Turkish population.

    PubMed

    Izmirli, Muzeyyen; Inandiklioglu, Nihal; Abat, Deniz; Alptekin, Davut; Demirhan, Osman; Tansug, Zuhtu; Bayazit, Yildirim

    2011-01-01

    Bladder cancer is the 9th most common cancer and is responsible for malignancy related death all on the world. Folate and folate related enzyme polymorphisms related to the cancer risk. The methylene tethrahydrofolate reductase (MTHFR) enzyme is folate related and association of bladder cancer and MTHFR gene. Our purpose was to assess the prevalence of MTHFR gene 677 CT and 1298 AC polymorphisms and Bladder cancer in Turkey. We intended that bladder cancer patients and controls and we used the Polymerase Chain Reaction (PCR) and Restriction Fragment Length Polymorphism (RFLP) methods. The MTHFR gene C677T and A1298C polymorphisms were associated with an increased risk of bladder cancer in our population (For the MTHFR gene C677T polymorphism and A1298C polymorphism; p=0.036<0.05; p=0.278>0.05 respectively). Consequently, the MTHFR gene C677T polymorphism augments the risk of bladder cancer in Turkey. PMID:22126575

  4. Evaluation of High Resolution Melting for MTHFR C677T Genotyping in Congenital Heart Disease

    PubMed Central

    Yue, Shuying; Zhang, Kun; Wang, Hui; Dong, Rui; Yang, Xiaomeng; Liu, Yi; Ma, Yanhui

    2016-01-01

    Background High resolution melting (HRM) is a simple, flexible and low-cost mutation screening technique. The methylenetetrahydrofolate reductase (MTHFR) gene encoding a critical enzyme, potentially affects susceptibility to some congenital defects like congenital heart disease (CHD). We evaluate the performance of HRM for genotyping of the MTHFR gene C677T locus in CHD cases and healthy controls of Chinese Han population. Methods A total of 315 blood samples from 147 CHD patients (male72, female 75) and 168 healthy controls (male 92, female 76) were enrolled in the study. HRM was utilized to genotype MTHFR C677T locus of all the samples. The results were compared to that of PCR-RFLP and Sanger sequencing. The association of the MTHFR C677T genotypes and the risk of CHD was analyzed using odds ratio with their 95% confidence interval (CIs) from unconditional logistic regression. Results All the samples were successfully genotyped by HRM within 1 hour and 30 minutes while at least 6 hours were needed for PCR-RFLP and sequencing. The genotypes of MTHFR C677T CC, CT, and TT were 9.52%, 49.66%, and 40.82% in CHD group but 29.17%, 50% and 20.83% in control group, which were identical using both methods of HRM and PCR-RFLP, demonstrating the sensitivity and specificity of HRM were all 100%. Conclusion MTHFR C677T is a potential risk factor for CHD in our local residents of Shandong province in China. HRM is a fast, sensitive, specific and reliable method for clinical application of genotyping. PMID:26990189

  5. [Genetic variant C677T in the MTHFR in women with recurrent early fetal loss].

    PubMed

    Ivanov, P; Kovacheva, K; Komsa-Penkova, R; Konova, E; Simeonova, M; Popov, I; Gecheva, S; Bozhinova, S; Tanchev, S; Tsafarov, M

    2007-01-01

    The aim of this study was to evaluate correlation of carrier status for thrombophilic gene mutation--C677T in the methylenetetrahydrofolate reductase (MTHFR) and recurrent early pregnancy loss. Recently inherited thrombophilia was discussed as a predisposed factor for early recurrent fetal loss (ERFL). We investigated carrier status for C677T genetic variant in 54 women with ERFL before 10 week of gestation and 67 women with one or more successful pregnancy. It was found significant prevalence of C677T genetic variant in MTHFR in women with ERFL compared with controls (p = 0.005). The significant high prevalence of C677T genetic variant in women with ERFL suggests that thrombophilia have an increased risk of early pregnancy loss and possibly, although the definition of the magnitude of risk will require prospective longitudinal studies. PMID:17974190

  6. Severe scoliosis in a patient with severe methylenetetrahydrofolate reductase deficiency.

    PubMed

    Munoz, Tatiana; Patel, Jinesh; Badilla-Porras, Ramses; Kronick, Jonathan; Mercimek-Mahmutoglu, Saadet

    2015-01-01

    Severe methylenetetrahydrofolate reductase (MTHFR) deficiency is a rare autosomal recessively inherited inborn error of folate metabolism. We report a new patient with severe MTHFR deficiency who presented at age 4 months with early onset severe scoliosis associated with severe hypotonia. Markedly decreased MTHFR enzyme activity (0.3 nmoles CHO/mg protein/h; reference range>9) and compound heterozygous mutations (c. 1304T>C; p.Phe435Ser and c.1539dup; p.Glu514Argfs∗24) in the MTHFR gene confirmed the diagnosis. She was treated with vitamin B12, folic acid and betaine supplementation and showed improvements in her developmental milestones and hypotonia. To the best of our knowledge, this is the first patient with MTHFR deficiency reported with severe early onset scoliosis. Despite the late diagnosis and treatment initiation, she showed favorable short-term neurodevelopmental outcome. This case suggests that homocysteine measurement should be included in the investigations of patients with developmental delay, hypotonia and scoliosis within first year of life prior to organizing genetic investigations. PMID:24726568

  7. Maternal Supplementary Folate Intake, Methylenetetrahydrofolate Reductase (MTHFR) C677T and A1298C Polymorphisms and the Risk of Orofacial Cleft in Iranian Children

    PubMed Central

    Ebadifar, Asghar; KhorramKhorshid, Hamid Reza; Kamali, Koorosh; Salehi Zeinabadi, Mehdi; Khoshbakht, Tayyebeh; Ameli, Nazila

    2015-01-01

    Background: The purpose of this study was to describe the association of MTHFR gene single nucleotide polymorphisms (C677T and A1298C) and maternal supplementary folate intake with orofacial clefts in the Iranian population. Methods: In this case-control study, peripheral venous blood was taken from 65 patients with orofacial clefts and 215 unaffected controls for DNA extraction and kept in EDTA for further analysis. The genotyping was carried out using Polymerase Chain Reaction (PCR) followed by Restriction Fragment Length Polymorphism (RFLP) and gel electrophoresis. Data were analyzed using Chi square test and logistic regression tests. Results: Genotype frequencies of 677TT were reported to be 13.5 and 36.1% in controls and CL/P patients, respectively, which showed a significant difference compared to CC as reference (OR=4.118; 95% CI=1.997–8.492; p=0.001). Conversely, 1298CC with frequencies of 10.8 and 12.7% in controls and patients, respectively, showed no significant difference compared to AA (OR=2.359; 95% CI=0.792–7.023; p=0.123). Comparing patients whose mothers did not report the folate supplement intake during pregnancy, to controls, it was observed that lack of folate intake was a predisposing factor for having a child with oral clefts (OR=5/718, p=0.000). Conclusion: Children carrying the 677TT variant of the MTHFR gene may have an increased risk of CL/P. In addition, the finding that the risk associated with this allele was obviously higher when the mothers didn’t use folic acid, supports the hypothesis that folic acid may play a role in the etiology of CL/P. PMID:26140186

  8. Study on Environmental Causes and SNPs of MTHFR, MS and CBS Genes Related to Congenital Heart Disease

    PubMed Central

    Liu, Yan; Huang, Peng; Lin, Ning; Sun, Xiaoru; Yu, Rongbin; Zhang, Yuanyuan; Qin, Yuming; Wang, Lijuan

    2015-01-01

    Purpose Congenital heart diseases (CHD) are among the most common birth defects in China. Environmental causes and folate metabolism changes may alter susceptibility to CHD. The aim of this study is to evaluate the relevant risk-factors of children with CHD and their mothers. Methods 138 children with CHD and 207 normal children for controls were recruited. Their mothers were also enlisted in this study and interviewed following a questionnaire about their pregnant history and early pregnancy situation. Five single nucleotide polymorphisms (SNPs) in methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MS) and cystathionine β-synthase (CBS) of mothers and children were genotyped. Results There were significant differences in the gender of children, occupation of mothers, family history with CHD, history of abortion, history of adverse pregnancy, early pregnancy health, fetus during pregnancy, pesticide exposure and drug exposure in CHD group and control group ( P < 0.05). Logistic regression analyses showed that after adjustment for above factors, MTHFR rs1801131 were significantly associated with their offspring CHD risk in mothers. Compared with the mothers whose MTHFR were rs1801131 AA and AC genotypes, the mothers who got a mutation of MTHFR rs1801131 CC genotypes had a 267% increase in risk of given birth of a CHD children (OR=3.67,95%CI=1.12-12.05). Meanwhile, MTHFR rs1801131 were significantly associated with CHD susceptibility in children (OR = 1.42, 95% CI = 1.00-2.44 in additive model). Conclusions Besides mothers’ social and fertility characteristics, our results suggested that the genetic variants in folate metabolism pathway might be one of the most related risk-factors of CHD. MTHFR rs1801131 were identified as loci in Chinese population that were involved in CHD. PMID:26035828

  9. MTHFR gene C677T polymorphism and type 2 diabetic nephropathy in Asian populations: a meta-analysis

    PubMed Central

    Chen, Haiyan; Wei, Fang; Wang, Lihua; Wang, Zhe; Meng, Jia; Jia, Lan; Sun, Guijiang; Zhang, Ruining; Li, Bo; Yu, Haibo; Pang, Haiyan; Bi, Xueqing; Dong, Hongye; Jiang, Aili; Wang, Lin

    2015-01-01

    Background: Many studies have suggested a correlation between the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene and diabetic nephropathy (DN), but their results are inconclusive. Methods: To confirm this correlation, we performed a meta-analysis of 15 studies. The dichotomous data are presented as odds ratios (OR) with 95% confidence intervals (CI). Results: The results of this study suggested that the MTHFR 677 T allele was more likely to increase the risk of DN in Asian (OR = 1.466, 95% CI = 1.143-1.880, P = 0.003), West Asian (OR = 1.750, 95% CI = 1.150-2.664, P = 0.009), and Chinese populations (OR = 2.162, 95% CI = 1.719-2.719, P = 0.001), but not in East Asian or Japanese populations. The carriers of the MTHFR 677 T allele were associated with progression of DN in the “5-10 year duration” group, but not in the “> 10 year duration” group (OR = 2.187, 95% CI = 1.787-2.677, P = 0.001). Conclusion: Development of DN is associated with MTHFR C677T polymorphisms in Asian populations, especially in early type 2 diabetes. PMID:26064261

  10. [Clinical comments on genetic marker prevalence (factor V Leiden, prothrombin 20210A and homozygous methylenetetrahydrofolate reductase form [Ho-MTHFR]): based on a study conducted in Health Department No. 19 of the Valencian Community].

    PubMed

    García-Hernández, M C; Romero Casanova, A; Marco Vera, P

    2007-01-01

    The prevalence of genetic markers in ETV disease patients in the 19th Health Department of Valencian Community were: FVL: 9.2%; PT20210 A: 10.5% and Ho-MTHFR: 23.7%. The FVL and PT20210 A prevalence results are lower respect to the literature, while Ho-MTHFR patients, have a higher prevalence with statistical significance difference respect the control group. We considered FVL, PT20210 A and Ho-MTHFR as ETV risk markers. The prevalence of genetic markers in healthy population of the same Health Department were: FVL: 5.8%; PT20210 A: 7.1%, and Ho-MTHFR: 7.7%. We must considered the specific study of these genetic risk markers (FVL, PT20210 A, Ho-MTHFR) in ETV disease affected subjects. The study of first degree relatives of the analyzed patients, should be of great utility to planified genetic advice and practice ETV prophylaxis. PMID:17306151

  11. Mthfr gene ablation enhances susceptibility to arsenic prenatal toxicity

    SciTech Connect

    Wlodarczyk, Bogdan J. Zhu, Huiping; Finnell, Richard H.

    2014-02-15

    Background: In utero exposure to arsenic is known to adversely affect reproductive outcomes. Evidence of arsenic teratogenicity varies widely and depends on individual genotypic differences in sensitivity to As. In this study, we investigated the potential interaction between 5,10-methylenetetrahydrofolate reductase (Mthfr) genotype and arsenic embryotoxicity using the Mthfr knockout mouse model. Methods: Pregnant dams were treated with sodium arsenate, and reproductive outcomes including: implantation, resorption, congenital malformation and fetal birth weight were recorded at E18.5. Results: When the dams in Mthfr{sup +/−} × Mthfr{sup +/−} matings were treated with 7.2 mg/kg As, the resorption rate increased to 43.4%, from a background frequency of 7.2%. The As treatment also induced external malformations (40.9%) and significantly lowered the average fetal birth weight among fetuses, without any obvious toxic effect on the dam. When comparing the pregnancy outcomes resulting from different mating scenarios (Mthfr{sup +/+} × Mthfr{sup +/−}, Mthfr{sup +/−} × Mthfr{sup +/−} and Mthfr{sup −/−} × {sup Mthfr+/−}) and arsenic exposure; the resorption rate showed a linear relationship with the number of null alleles (0, 1 or 2) in the Mthfr dams. Fetuses from nullizygous dams had the highest rate of external malformations (43%) and lowest average birth weight. When comparing the outcomes of reciprocal matings (nullizygote × wild-type versus wild-type × nullizygote) after As treatment, the null dams showed significantly higher rates of resorptions and malformations, along with lower fetal birth weights. Conclusions: Maternal genotype contributes to the sensitivity of As embryotoxicity in the Mthfr mouse model. The fetal genotype, however, does not appear to affect the reproductive outcome after in utero As exposure. - Highlights: • An interaction between Mthfr genotype and arsenic embryotoxicity is presented. • Maternal Mthfr genotype contributes to the sensitivity of As embryotoxicity. • Fetal Mthfr genotype does not affect the reproductive outcome after As exposure.

  12. Free-floating thrombus of the carotid artery with a homozygous methylenetetrahydrofolate reductase gene mutation: a case report.

    PubMed

    Colak, Necmettin; Nazli, Yunus; Kosehan, Dilek; Alpay, Mehmet Fatih; Cakir, Omer

    2013-02-01

    Free-floating thrombus (FFT) of the carotid artery is a rare condition of currently unknown etiology. We describe a symptomatic patient with an FFT in the left common carotid artery. A duplex ultrasonography scan showed the presence of a mobile floating thrombus moving in cyclical motion with the cardiac cycles in the left common carotid artery. During emergency surgery, an FFT was seen at this location and removed. No underlying wall defect was seen at the time of surgery. In a genetic screening test, TT homozygous for the methylenetetrahydrofolate reductase (MTHFR) C677T genetic polymorphisms was detected. The patient recovered uneventfully, with no neurogical events. Lifelong anticoagulant therapy was recommended. An aggressive surgical approach is recommended in the patient to prevent embolic episodes. PMID:22101856

  13. Association between MTHFR 677C-T polymorphism and alcohol dependence according to Lesch and Babor typology.

    PubMed

    Benyamina, Amine; Saffroy, Raphal; Blecha, Lisa; Pham, Patrick; Karila, Laurent; Debuire, Brigitte; Lemoine, Antoinette; Reynaud, Michel

    2009-09-01

    Prior studies have associated 677C-T Methylenetetrahydrofolate reductase (MTHFR) gene polymorphism with decreased enzymatic activity and modified homocysteine regulation. This study determines and compares MTHFR 677C-T distribution and examines its consequences on homocysteine metabolism and alcohol dependence in alcoholic patients classified according to the Babor and Lesch typologies. MTHFR TT genotype was more prevalent in AD patients with milder alcohol dependence (Babor type A) and with Lesch type 3, associated with depression. MTHFR TT was also associated with hyperhomocysteinemia. Determining MTHFR 677C-T genotype, folate and vitamin B12 levels could assist physicians in identifying type 3 patients and improve addictions management. PMID:19650814

  14. Relationship of MTHFR gene polymorphisms with renal and cardiac disease

    PubMed Central

    Trovato, Francesca M; Catalano, Daniela; Ragusa, Angela; Martines, G Fabio; Pirri, Clara; Buccheri, Maria Antonietta; Di Nora, Concetta; Trovato, Guglielmo M

    2015-01-01

    AIM: To investigate the effects of different methylenetetrahydrofolate reductase (MTHFR) 677C>T gene polymorphism and hyperhomocysteinemia for the development of renal failure and cardiovascular events, which are controversial. METHODS: We challenged the relationship, if any, of MTHFR 677C>T and MTHFR 1298A>C polymorphisms with renal and heart function. The present article is a reappraisal of these concepts, investigating within a larger population, and including a subgroup of dialysis patients, if the two most common MTHFR polymorphisms, C677T and A1298C, as homozygous, heterozygous or with a compound heterozygous state, show different association with chronic renal failure requiring hemodialysis. MTHFR polymorphism could be a favorable evolutionary factor, i.e., a protective factor for many ominous conditions, like cancer and renal failure. A similar finding was reported in fatty liver disease in which it is suggested that MTHFR polymorphisms could have maintained and maintain their persistence by an heterozygosis advantage mechanism. We studied a total of 630 Italian Caucasian subject aged 54.60 16.35 years, addressing to the increased hazard of hemodialysis, if any, according to the studied MTHFR genetic polymorphisms. RESULTS: A favorable association with normal renal function of MTHFR polymorphisms, and notably of MTHFR C677T is present independently of the negative effects of left ventricular hypertrophy, increased Intra-Renal arterial Resistance and hyperparathyroidism. CONCLUSION: MTHFR gene polymorphisms could have a protective role on renal function as suggested by their lower frequency among our dialysis patients in end-stage renal failure; differently, the association with left ventricular hypertrophy and reduced left ventricular relaxation suggest some type of indirect, or concurrent mechanism. PMID:25664255

  15. A foreign dihydrofolate reductase gene in transgenic mice acts as a dominant mutation.

    PubMed Central

    Gordon, J W

    1986-01-01

    We have produced 17 lines of transgenic mice by microinjecting a full-length cDNA clone of an altered dihydrofolate reductase (dhfr) gene. The protein specified by this gene carries a point mutation which triples its Km for dihydrofolate and reduces substrate turnover 20-fold relative to the wild-type enzyme. Transgenic mice from different pedigrees, several of which carry a single copy of this gene in different integration sites, manifest an array of similar developmental abnormalities including growth stunting, reduced fertility, pigmentation changes, and skeletal defects. These defects appear in animals heterozygous for the foreign gene. RNA analyses demonstrate significant expression of the cDNA in newborn mice and adult tissues. These findings show that the additional dhfr gene exerts its mutational effects in a dominant fashion, and therefore the data indicate that transgenic mice can serve as models for elucidating mechanisms of dominant mutagenesis. Images PMID:3785192

  16. Murine diet/tissue and human brain tumorigenesis alter Mthfr/MTHFR 5'-end methylation.

    PubMed

    Lévesque, Nancy; Leclerc, Daniel; Gayden, Tenzin; Lazaris, Anthoula; De Jay, Nicolas; Petrillo, Stephanie; Metrakos, Peter; Jabado, Nada; Rozen, Rima

    2016-04-01

    Polymorphisms and decreased activity of methylenetetrahydrofolate reductase (MTHFR) are linked to disease, including cancer. However, epigenetic regulation has not been thoroughly studied. Our goal was to generate DNA methylation profiles of murine/human MTHFR gene regions and examine methylation in brain and liver tumors. Pyrosequencing in four murine tissues revealed minimal DNA methylation in the CpG island. Higher methylation was seen in liver or intestine in the CpG island shore 5' to the upstream translational start site or in another region 3' to the downstream start site. In the latter region, there was negative correlation between expression and methylation. Three orthologous regions were investigated in human MTHFR, as well as a fourth region between the two translation start sites. We found significantly increased methylation in three regions (not the CpG island) in pediatric astrocytomas compared with control brain, with decreased expression in tumors. Methylation in hepatic carcinomas was also increased in the three regions compared with normal liver, but the difference was significant for only one CpG. This work, the first overview of the Mthfr/MTHFR epigenetic landscape, suggests regulation through methylation in some regions, demonstrates increased methylation/decreased expression in pediatric astrocytomas, and should serve as a resource for future epigenetic studies. PMID:26951114

  17. Folate intake, MTHFR genotype, and sex modulate choline metabolism in mice.

    PubMed

    Chew, Tina W; Jiang, Xinyin; Yan, Jian; Wang, Wei; Lusa, Amanda L; Carrier, Bradley J; West, Allyson A; Malysheva, Olga V; Brenna, J Thomas; Gregory, Jesse F; Caudill, Marie A

    2011-08-01

    Choline and folate are interrelated in 1-carbon metabolism, mostly because of their shared function as methyl donors for homocysteine remethylation. Folate deficiency and mutations of methylenetetrahydrofolate reductase (MTHFR) reduce the availability of a major methyl donor, 5-methyltetrahydrofolate, which in turn may lead to compensatory changes in choline metabolism. This study investigated the hypothesis that reductions in methyl group supply, either due to dietary folate deficiency or Mthfr gene deletion, would modify tissue choline metabolism in a sex-specific manner. Mthfr wild type (+/+) or heterozygous (+/-) knockout mice were randomized to a folate-deficient or control diet for 8 wk during which time deuterium-labeled choline (d9-choline) was consumed in the drinking water (~10 μmol/d). Mthfr heterozygosity did not alter brain choline metabolite concentrations, but it did enhance their labeling in males (P < 0.05) and tended to do so in females (P < 0.10), a finding consistent with greater turnover of dietary choline in brains of +/- mice. Dietary folate deficiency in females yielded 52% higher (P = 0.027) hepatic glycerophosphocholine, which suggests that phosphatidylcholine (PtdCho) degradation was enhanced. Labeling of the hepatic PtdCho in d3 form was also reduced (P < 0.001) in females, which implies that fewer of the dietary choline-derived methyl groups were used for de novo PtdCho biosynthesis under conditions of folate insufficiency. Males responded to folate restriction with a doubling (P < 0.001) of hepatic choline dehydrogenase transcripts, a finding consistent with enhanced conversion of choline to the methyl donor, betaine. Collectively, these data show that several adaptations in choline metabolism transpire as a result of mild perturbations in folate metabolism, presumably to preserve methyl group homeostasis. PMID:21697299

  18. A distal mutation perturbs dynamic amino acid networks in dihydrofolate reductase.

    PubMed

    Boehr, David D; Schnell, Jason R; McElheny, Dan; Bae, Sung-Hun; Duggan, Brendan M; Benkovic, Stephen J; Dyson, H Jane; Wright, Peter E

    2013-07-01

    Correlated networks of amino acids have been proposed to play a fundamental role in allostery and enzyme catalysis. These networks of amino acids can be traced from surface-exposed residues all the way into the active site, and disruption of these networks can decrease enzyme activity. Substitution of the distal Gly121 residue in Escherichia coli dihydrofolate reductase results in an up to 200-fold decrease in the hydride transfer rate despite the fact that the residue is located 15 Å from the active-site center. In this study, nuclear magnetic resonance relaxation experiments are used to demonstrate that dynamics on the picosecond to nanosecond and microsecond to millisecond time scales are changed significantly in the G121V mutant of dihydrofolate reductase. In particular, picosecond to nanosecond time scale dynamics are decreased in the FG loop (containing the mutated residue at position 121) and the neighboring active-site loop (the Met20 loop) in the mutant compared to those of the wild-type enzyme, suggesting that these loops are dynamically coupled. Changes in methyl order parameters reveal a pathway by which dynamic perturbations can be propagated more than 25 Å across the protein from the site of mutation. All of the enzyme complexes, including the model Michaelis complex with folate and nicotinamide adenine dinucleotide phosphate bound, assume an occluded ground-state conformation, and we do not observe sampling of a higher-energy closed conformation by (15)N R2 relaxation dispersion experiments. This is highly significant, because it is only in the closed conformation that the cofactor and substrate reactive centers are positioned for reaction. The mutation also impairs microsecond to millisecond time scale fluctuations that have been implicated in the release of product from the wild-type enzyme. Our results are consistent with an important role for Gly121 in controlling protein dynamics critical for enzyme function and further validate the dynamic energy landscape hypothesis of enzyme catalysis. PMID:23758161

  19. A distal mutation perturbs dynamic amino acid networks in dihydrofolate reductase

    PubMed Central

    Bae, Sung-Hun; Duggan, Brendan M.; Benkovic, Stephen J.; Dyson, H. Jane; Wright, Peter E

    2013-01-01

    Correlated networks of amino acids have been proposed to play a fundamental role in allostery and enzyme catalysis. These networks of amino acids can be traced from surface-exposed residues all the way into the active site, and disruption of these networks can decrease enzyme activity. Substitution of the distal Gly121 residue in E.coli dihydrofolate reductase results in up to a 200-fold decrease in the hydride transfer rate despite the fact that the residue is located 15 Å from the active-site center. In the present study, NMR relaxation experiments are used to demonstrate that dynamics on the ps-ns and μs-ms timescales are changed significantly in the G121V mutant of dihydrofolate reductase. In particular, ps-ns timescale dynamics are decreased in the FG loop (containing the mutated residue 121) and the neighboring active-site loop (the Met20 loop) in the mutant compared to wild-type enzyme, suggesting that these loops are dynamically coupled. Changes in methyl order parameters reveal a pathway by which dynamic perturbations can be propagated more than 25 Å across the protein from the site of mutation. All of the enzyme complexes, including the model Michaelis complex with folate and NADP+ bound, assume an occluded ground state conformation, and we do not observe sampling of a higher energy closed conformation by 15N R2 relaxation dispersion. This is highly significant, since it is only in the closed conformation that the cofactor and substrate reactive centers are positioned for reaction. The mutation also impairs μs - ms timescale fluctuations that have been implicated in product release from the wild type enzyme. Our results are consistent with an important role for Gly121 in controlling protein dynamics critical for enzyme function and further validate the dynamic energy landscape hypothesis of enzyme catalysis. PMID:23758161

  20. Direct selection for mutations affecting specific splice sites in a hamster dihydrofolate reductase minigene.

    PubMed Central

    Chen, I T; Chasin, L A

    1993-01-01

    A Chinese hamster cell line containing an extra exon 2 (50 bp) inserted into a single intron of a dihydrofolate reductase (dhfr) minigene was constructed. The extra exon 2 was efficiently spliced into the RNA, resulting in an mRNA that is incapable of coding for the DHFR enzyme. Mutations that decreased splicing of this extra exon 2 caused it to be skipped and so produced normal dhfr mRNA. In contrast to the parental cell line, the splicing mutants display a DHFR-positive growth phenotype. Splicing mutants were isolated from this cell line after treatment with four different mutagens (racemic benzo[c]phenanthrene diol epoxide, ethyl methanesulfonate, ethyl nitrosourea, and UV irradiation). By polymerase chain reaction amplification and direct DNA sequencing, we determined the base changes in 66 mutants. Each of the mutagens generated highly specific base changes. All mutations were single-base substitutions and comprised 24 different changes distributed over 16 positions. Most of the mutations were within the consensus sequences at the exon 2 splice donor, acceptor, and branch sites. The RNA splicing patterns in the mutants were analyzed by quantitative reverse transcription-polymerase chain reaction. The recruitment of cryptic sites was rarely seen; simple exon skipping was the predominant mutant phenotype. The wide variety of mutations that produced exon skipping suggests that this phenotype is the typical consequence of splice site damage and supports the exon definition model of splice site selection. A few mutations were located outside the consensus sequences, in the exon or between the branch point and the polypyrimidine tract, identifying additional positions that play a role in splice site definition. That most of these 66 mutations fell within consensus sequences in this near-saturation mutagenesis suggests that splicing signals beyond the consensus may consist of robust RNA structures. Images PMID:8417332

  1. C677T methylenetetrahydrofolate reductase and plasma homocysteine levels among Thai vegans and omnivores.

    PubMed

    Kajanachumpol, Saowanee; Atamasirikul, Kalayanee; Tantibhedhyangkul, Phieuvit

    2013-01-01

    Hyperhomocysteinemia among vegetarians and vegans is caused mostly by vitamin B12 deficiency. A C-to-T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene results in a thermolabile MTHFR, which may affect homocysteine (Hcy) levels. The importance of this gene mutation among populations depends on the T allele frequency. Blood Hcy, vitamin B12, folate, vitamin B6, and MTHFR C677T mutation status were determined in 109 vegans and 86 omnivores aged 30 - 50 years. The vegans had significantly higher Hcy levels than the omnivores, geometric means (95 % CI) 19.2 (17.0 - 21.7) µmol/L vs. 8.53 (8.12 - 8.95) µmol/L, p < 0.001. A C-to-T mutation in the vegans increased plasma Hcy, albeit insignificantly; geometric means 18.2 µmol/L, 20.4 µmol/L, and 30.0 µmol/L respectively in CC, CT, and TT MTHFR genotypes. There was also a significant decrease in serum folate; geometric means 12.1 ng/mL, 9.33 ng/mL, and 7.20 ng/mL respectively, in the CC, CT, and TT mutants, p = 0.006, and particularly, in the TT mutant compared with the CC wild type, 7.20 ng/mL vs. 12.1 ng/mL, p = 0.023. These findings were not seen in the omnivores. It was concluded that hyperhomocysteinemia is prevalent among Thai vegans due to vitamin B12 deficiency. C-to-T MTHFR mutation contributes only modestly to the hyperhomocysteinemia. PMID:24491881

  2. In human alleles specific variation of MTHFR C677T and A1298C associated "risk factor" for the development of ovarian cancer.

    PubMed

    Singh, Anupama; Pandey, S; Pandey, L K; Saxena, Ajit K

    2015-01-01

    Etiopathology of tumor biology is highly complex and ovarian cancer is one of the important gynaecological neoplasia associated with high risk of mortality rate. Methlenetetrahydrofolate reductase (MTHFR) mutation are commonly linked to folate metabolism with increased risk factor for the development of neural tube defects, recurrent pregnancy loss and development of several type of cancer but genetic interaction between two alleles of MTHFR has been poorly defined in ovarian cancer in India. Hence, present study becomes imperative with the aim to assess the alleles frequency of MTHFR (C677T & A1298C) gene polymorphism using PCR based RFLP analysis. The O.R at 95% confidence interval (C.I.) was computed between cases and their respective controls to determine "risk factor". Interestingly, our findings reveals highly significant (p < 0.001) difference in heterozygous (CT) condition of C677T allele by computing odd ratio (0.12 at 95% C.I, 0.021-0.0428; P for trend = 0.001) in controls and (0.34 at 95% C.I, 0.074-1.530; P for trend = 0.198) cases, suggesting that three time increase the "risk factor" for genetic susceptibility of MTHFR "T" allele for the development of ovarian carcinoma. PMID:26259392

  3. The 844ins68 cystathionine beta-synthase and C677T MTHFR gene polymorphism and the vaso-occlusive event risk in sickle cell disease

    PubMed Central

    Alves Jacob, Maza; da Cunha Bastos, Celso; Regina Bonini-Domingos, Claudia

    2011-01-01

    Introduction Sickle cell disease (SCD) is an inflammatory condition with an increase in the adhesion of sickled erythrocytes, and it is a potential cause of vaso-occlusive episodes, an event related to clinical manifestations, morbidity and mortality. The cystathionine beta-synthase enzyme gene (CBS) and the methylenetetrahydrofolate reductase enzyme gene (MTHFR) are risk factors for thromboembolic disorders. This study evaluated the frequency of the 844ins68 CBS and C677T MTHFR gene polymorphisms and their possibility to be risk factors for vaso-occlusive crises. Material and methods In total 91 blood samples from SCD patients were studied by PCR-RFLP and PCR-allele-specific, for the SCD genotype confirmation and polymorphism identification. Results The presence of clinical manifestations related to vaso-occlusive crises were more frequent among patients with the Hb SS genotype (p = 0.007). The CBS enzyme gene was three times more frequent (p = 0.011) among patients with vaso-occlusive complications. The MTHFR gene mutation frequency showed no increased risk for vaso-occlusive crises in SCD patients (p = 0.193). The interaction between the two polymorphisms was evaluated in 12.08% of the SCD patients and doubled the vaso-occlusive disease risk (relative risk: 2.16). Conclusions We conclude that the presence of 844ins68 CBS and C677T MTHFR gene polymorphism was a risk factor for vaso-occlusive episodes in the SCD patients evaluated. PMID:22291740

  4. Thioredoxin Reductase 2 (TXNRD2) Mutation Associated With Familial Glucocorticoid Deficiency (FGD)

    PubMed Central

    Prasad, Rathi; Chan, Li F.; Hughes, Claire R.; Kaski, Juan P.; Kowalczyk, Julia C.; Savage, Martin O.; Peters, Catherine J.; Nathwani, Nisha; Clark, Adrian J. L.; Metherell, Louise A.

    2014-01-01

    Context: Classic ACTH resistance, due to disruption of ACTH signaling, accounts for the majority of cases of familial glucocorticoid deficiency (FGD). Recently FGD cases caused by mutations in the mitochondrial antioxidant, nicotinamide nucleotide transhydrogenase, have highlighted the importance of redox regulation in steroidogenesis. Objective: We hypothesized that other components of mitochondrial antioxidant systems would be good candidates in the etiology of FGD. Design: Whole-exome sequencing was performed on three related patients, and segregation of putative causal variants confirmed by Sanger sequencing of all family members. A TXNRD2-knockdown H295R cell line was created to investigate redox homeostasis. Setting: The study was conducted on patients from three pediatric centers in the United Kingdom. Patients: Seven individuals from a consanguineous Kashmiri kindred, six of whom presented with FGD between 0.1 and 10.8 years, participated in the study. Interventions: There were no interventions. Main Outcome Measure: Identification and functional interrogation of a novel homozygous mutation segregating with the disease trait were measured. Results: A stop gain mutation, p.Y447X in TXNRD2, encoding the mitochondrial selenoprotein thioredoxin reductase 2 (TXNRD2) was identified and segregated with disease in this extended kindred. RT-PCR and Western blotting revealed complete absence of TXNRD2 in patients homozygous for the mutation. TXNRD2 deficiency leads to impaired redox homeostasis in a human adrenocortical cell line. Conclusion: In contrast to the Txnrd2-knockout mouse model, in which embryonic lethality as a consequence of hematopoietic and cardiac defects is described, absence of TXNRD2 in humans leads to glucocorticoid deficiency. This is the first report of a homozygous mutation in any component of the thioredoxin antioxidant system leading to inherited disease in humans. PMID:24601690

  5. A transgenic Neospora caninum strain based on mutations of the dihydrofolate reductase-thymidylate synthase gene.

    PubMed

    Pereira, Luiz Miguel; Baroni, Luciana; Yatsuda, Ana Patrícia

    2014-03-01

    Neospora caninum is an Apicomplexa parasite related to abortion and losses of fertility in cattle. The amenability of Toxoplasma gondii and Plasmodium to genetic manipulation offers several tools to determine the invasion and replication processes, which support posterior strategies related to the combat of these diseases. For Plasmodium the use of pyrimethamine as an auxiliary drug on malaria treatment has been affected by the rise of resistant strains and the analyses on Dihydrofolate reductase-thymidylate synthase (DHFR-TS) gene indicated several point mutations. In this work we developed a method for stable insertion of genes based on resistance to pyrimethamine. For that, the coding sequence of NcDHFR-TS (Dihydrofolate reductase-thymidylate synthase) was point mutated in two amino acids, generating DHFRM2M3. The DHFRM2M3 flanked by the promoter and 3'UTR of Ncdhfr-ts (Ncdhfr-DHFRM2M3) conferred resistance to pyrimethamine after transfection. For illustration of stability and expression, the cassette Ncdhfr-DHFRM2M3 was ligated to the reporter gene Lac-Z (β-galactosidase enzyme) controlled by the N. caninum tubulin promoter and was transfected and selected in N. caninum. The cassette was integrated into the genome and the selected tachyzoites expressed Lac-Z, allowing the detection of tachyzoites by the CPRG reaction and X-gal precipitation. The obtainment of transgenic N. caninum resistant to pyrimethamine confirms the effects on DHFR-TS among the Apicomplexa members and will support future approaches on pholate inhibitors for N. caninum prophylaxis. The construction of stable tachyzoites based on vectors with N. caninum promoters initiates the molecular manipulation of this parasite independently of T. gondii. PMID:24440296

  6. Ambiguous external genitalia due to defect of 5-α-reductase in seven Iraqi patients: prevalence of a novel mutation.

    PubMed

    Di Marco, Chiara; Bulotta, Anna Lavinia; Varetti, Concetta; Dosa, Laura; Michelucci, Angela; Baldinotti, Fulvia; Meucci, Daniela; Castagnini, Cinzia; Lo Rizzo, Caterina; Di Maggio, Giovanni; Simi, Paolo; Mari, Francesca; Bertelloni, Silvano; Renieri, Alessandra; Messina, Mario

    2013-09-10

    We report on seven Iraqi patients with 46,XY karyotype and ambiguous genitalia characterized by perineo-scrotal hypospadias, bifid scrotum, clitoris like phallus, palpable testes in inguinal canal and pseudovagina. Patients were raised five as females and two as males. They are all unrelated with the exception of two couples of brothers. The diagnosis of 5-α-reductase-2 deficiency syndrome was first hypothesized on clinical grounds and then confirmed by molecular analysis. Direct sequencing analysis of the SRD5A2 gene revealed in five patients a novel homozygous frame-shift mutation (c.453delC) and in two related patients a previous reported missense mutation. The presence of the same mutation in unrelated patients of the same population suggests a possible founder effect. This report brings the 5-α-reductase-2 deficiency syndrome to the attention of clinical geneticists and child surgeons and discusses the appropriate clinical and surgical strategies for treating these patients. PMID:23664981

  7. [Resistance to acenocoumarol revealing a missense mutation of the vitamin K epoxyde reductase VKORC1: a case report].

    PubMed

    Mboup, M C; Dia, K; Ba, D M; Fall, P D

    2015-02-01

    A significant proportion of the interindividual variability of the response to vitamin K antagonist (VKA) treatment has been associated with genetic factors. Genetic variations affecting the vitamin K epoxide reductase complex subunit 1 (VKORC1) are associated with hypersensitivity or rarely with resistance to VKA. We report the case of a black women patient who presents a resistance to acenocoumarol. Despite the use of high doses of acenocoumarol (114 mg/week) for the treatment of recurrent pulmonary embolism, the International Normalized Ratio was below the therapeutic target. This resistance to acenocoumarol was confirmed by the identification of a missense mutation Val66Met of the vitamin K epoxide reductase. PMID:24095214

  8. The prevalence of folate-remedial MTHFR enzyme variants in humans

    PubMed Central

    Marini, Nicholas J.; Gin, Jennifer; Ziegle, Janet; Keho, Kathryn Hunkapiller; Ginzinger, David; Gilbert, Dennis A.; Rine, Jasper

    2008-01-01

    Studies of rare, inborn metabolic diseases establish that the phenotypes of some mutations in vitamin-dependent enzymes can be suppressed by supplementation of the cognate vitamin, which restores function of the defective enzyme. To determine whether polymorphisms exist that more subtly affect enzymes yet are augmentable in the same way, we sequenced the coding region of a prototypical vitamin-dependent enzyme, methylenetetrahydrofolate reductase (MTHFR), from 564 individuals of diverse ethnicities. All nonsynonymous changes were evaluated in functional in vivo assays in Saccharomyces cerevisiae to identify enzymatic defects and folate remediability of impaired alleles. We identified 14 nonsynonymous changes: 11 alleles with minor allele frequencies <1% and 3 common alleles (A222V, E429A, and R594Q). Four of 11 low-frequency alleles affected enzyme function, as did A222V. Of the five impaired alleles, four could be restored to normal functionality by elevating intracellular folate levels. All five impaired alleles mapped to the N-terminal catalytic domain of the enzyme, whereas changes in the C-terminal regulatory domain had little effect on activity. Impaired activity correlated with the phosphorylation state of MTHFR, with more severe mutations resulting in lower abundance of the phosphorylated protein. Significantly, diploid yeast heterozygous for mutant alleles were impaired for growth, particularly with lower folate supplementation. These results suggested that multiple less-frequent alleles, in aggregate, might significantly contribute to metabolic dysfunction. Furthermore, vitamin remediation of mutant enzymes may be a common phenomenon in certain domains of proteins. PMID:18523009

  9. Prospective study of MTHFR genetic polymorphisms as a possible etiology of male infertility.

    PubMed

    Li, S-S; Li, J; Xiao, Z; Ren, A-G; Jin, L

    2014-01-01

    The aim of this study was to explore the relationship between 2 genetic polymorphisms of the methylenetetrahydrofolate reductase gene (MTHFR), C677T and A1298C, and determine the long-term reproductive outcome in infertile men. This was a prospective study conducted in an andrology clinic. Men with a 1-year history of infertility were assessed for the MTHFR polymorphisms at a 5-year follow-up. We compared the MTHFR C677T and A1298C polymorphisms by polymerase chain reaction-restriction fragment length polymorphism between men who did and did not bear children during follow-up. Of the 215 men who were infertile at 1 year, 82 (38.1%) remained infertile and 133 (61.9%) achieved natural conception during the 5-year follow-up, with the highest rate in the first year (32.6%). The MTHFR 677TT genotype (homozygote) was associated with a substantially increased risk of infertility during follow-up [odds ratio (OR) = 10.242; 95% confidence interval (CI) = 1.257-83.464] relative to the MTHFR 677CC genotype (wild-type). Risk of infertility was not increased by the MTHFR A1298C polymorphism alone, but was increased by the combination of polymorphisms MTHFR C677T and MTHFR A1298C (OR = 11.818; 95%CI = 1.415-98.674). The homozygous MTHFR C677T genotype was a risk factor for male infertility during 5-year follow-up, whereas a correlation between MTHFR A1298C and infertility was not observed. The MTHFR C677T and MTHFR A1298C polymorphisms had additive effects on male infertility. PMID:24737513

  10. Sex-dependent behavioral effects of Mthfr deficiency and neonatal GABA potentiation in mice.

    PubMed

    Levav-Rabkin, Tamar; Blumkin, Elinor; Galron, Dalia; Golan, Hava M

    2011-01-20

    The methylenetetrahydrofolate reductase (Mthfr) gene and/or abnormal homocysteine-folate metabolism are associated with increased risk for birth defects and neuropsychiatric diseases. In addition, disturbances of the GABAergic system in the brain as well as Mthfr polymorphism are associated with neurodevelopmental disorders such as schizophrenia and autism. In the present study we performed behavioral phenotyping of male and female Mthfr mice (wild type and their heterozygous littermates). The present study addresses two main questions: (1) genetic susceptibility, as examined by effects of Mthfr deficiency on behavior (Experiment 1) and (2) possible gene-drug interactions as expressed by behavioral phenotyping of Mthfr-deficient mice neonatally exposed to the GABA potentiating drug GVG (Experiment 2). Newborn development was slightly influenced by Mthfr genotype per se (Experiment 1); however the gene-drug interaction similarly affected reflex development in both male and female offspring (Experiment 2). Hyperactivity was demonstrated in Mthfr heterozygous male mice (Experiment 1) and due to GVG treatment in both Wt and Mthfr+/- male and female mice (Experiment 2). The gene-environment interaction did not affect anxiety-related behavior of male mice (Experiment 2). In female mice, gene-treatment interactions abolished the reduced anxiety observed due to GVG treatment and Mthfr genotype (Experiment 2). Finally, recognition memory of adult mice was impaired due to genotype, treatment and the gene-treatment combination in a sex-independent manner (Experiment 2). Overall, Mthfr deficiency and/or GABA potentiation differentially affect a spectrum of behaviors in male and female mice. This study is the first to describe behavioral phenotypes due to Mthfr genotype, GVG treatment and the interaction between these two factors. The behavioral outcomes suggest that Mthfr deficiency modulates the effects of GABA potentiating drugs. These findings suggest that future treatment strategies should consider a combination of genotyping with drug regimens. PMID:20813139

  11. Multiple origins of resistance-conferring mutations in Plasmodium vivax dihydrofolate reductase

    PubMed Central

    Hawkins, Vivian N; Auliff, Alyson; Prajapati, Surendra Kumar; Rungsihirunrat, Kanchana; Hapuarachchi, Hapuarachchige C; Maestre, Amanda; O'Neil, Michael T; Cheng, Qin; Joshi, Hema; Na-Bangchang, Kesara; Sibley, Carol Hopkins

    2008-01-01

    Background In order to maximize the useful therapeutic life of antimalarial drugs, it is crucial to understand the mechanisms by which parasites resistant to antimalarial drugs are selected and spread in natural populations. Recent work has demonstrated that pyrimethamine-resistance conferring mutations in Plasmodium falciparum dihydrofolate reductase (dhfr) have arisen rarely de novo, but spread widely in Asia and Africa. The origin and spread of mutations in Plasmodium vivax dhfr were assessed by constructing haplotypes based on sequencing dhfr and its flanking regions. Methods The P. vivax dhfr coding region, 792 bp upstream and 683 bp downstream were amplified and sequenced from 137 contemporary patient isolates from Colombia, India, Indonesia, Papua New Guinea, Sri Lanka, Thailand, and Vanuatu. A repeat motif located 2.6 kb upstream of dhfr was also sequenced from 75 of 137 patient isolates, and mutational relationships among the haplotypes were visualized using the programme Network. Results Synonymous and non-synonymous single nucleotide polymorphisms (SNPs) within the dhfr coding region were identified, as was the well-documented in-frame insertion/deletion (indel). SNPs were also identified upstream and downstream of dhfr, with an indel and a highly polymorphic repeat region identified upstream of dhfr. The regions flanking dhfr were highly variable. The double mutant (58R/117N) dhfr allele has evolved from several origins, because the 58R is encoded by at least 3 different codons. The triple (58R/61M/117T) and quadruple (57L/61M/117T/173F, 57I/58R/61M/117T and 57L/58R/61M/117T) mutant alleles had at least three independent origins in Thailand, Indonesia, and Papua New Guinea/Vanuatu. Conclusion It was found that the P. vivax dhfr coding region and its flanking intergenic regions are highly polymorphic and that mutations in P. vivax dhfr that confer antifolate resistance have arisen several times in the Asian region. This contrasts sharply with the selective sweep of rare antifolate resistant alleles observed in the P. falciparum populations in Asia and Africa. The finding of multiple origins of resistance-conferring mutations has important implications for drug policy. PMID:18442404

  12. Short communication: point mutations in the dihydrofolate reductase and dihydropteroate synthase genes of Plasmodium falciparum isolates from Colombia.

    PubMed

    Schmider, Nadja; Peyerl-Hoffmann, Gaby; Restrepo, Marcos; Jelinek, Tomas

    2003-02-01

    Point mutations in the dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS) genes of Plasmodium falciparum can lead to an increasing resistance of P. falciparum to pyrimethamine/sulphadoxine. We examined the prevalence of these mutations in 36 samples from Colombia. Analysed by polymerase chain reaction (PCR) for infection with P. falciparum, 25 (69%) tested positive. These positive isolates were tested further for point mutations in the genes of DHFR (codons 16, 51, 59, 108 and 164) and DHPS (codons 436, 437, 540, 581 and 613) by nested PCR and following mutation-specific restriction enzyme digestion. Gene mutations occurred in both the DHFR and DHPS gene of the Colombian isolates, suggesting that resistance to antifolate drugs exists or may develop soon in Colombia. PMID:12581437

  13. The association between methylene-tetrahydrofolate reductase gene polymorphism and lung cancer risk.

    PubMed

    Arslan, Sulhattin; Karadayi, Sule; Yildirim, Malik Ejder; Ozdemir, Ozturk; Akkurt, Ibrahim

    2011-02-01

    This study aimed to determine the relation between methylene-tetrahydrofolate reductase (MTHFR) gene polymorphism and lung cancer risk and the frequency of this polymorphism. The study involved 64 lung cancer patients (the study group) with definitive diagnosis and 61 noncancerous subjects (the control group). MTHFR C677T and A1298C mutation analysis was made using DNA isolated from peripheric blood and multiplex PCR and reverse hybridization strip test. Eighty-four percent of the patients were male. The age, gender, and history of alcohol use of the patients and control group were statistically similar. While MTHFR 677T and 677C allele frequency was 0.33 and 0.67 in the patients respectively, it was 0.29 and 0.71 in the control group. The frequencies of MTHFR 1298C and 1298A were 0.33 and 0.67 in the patients, and it was 0.31 and 0.69 in the control group respectively. When MTHFR 677TT and 677CT genotypes were compared with 677CC genotype, lung cancer risk was 2.4 times higher in the 677TT genotype. When MTHFR 1298AC and 1298CC genotypes were compared with 1298AA genotype, lung cancer risk was 1.5 times higher in 1298CC genotype. According to the results, allele frequency of homozygote T and C was high in lung cancer patients. It was 3.05 and 1.29 times higher in smokers than in non-smokers, and 3.05 and 1.64 times higher in males than in females; 3.0 and 2.44 times higher in those with non-small cell lung cancer than in those with small-cell lung cancer. PMID:20532637

  14. Association of MTHFR genetic polymorphisms with venous thromboembolism in Uyghur population in Xinjiang, China

    PubMed Central

    Li, Zhao; Yadav, Umesh; Mahemuti, Ailiman; Tang, Bao-Peng; Upur, Halmurat

    2015-01-01

    Background: The aim of this study was to reveal the association between Methylene tetrahydrofolate reductase (MTHFR) gene mutations (C677T, A1298C and C1317T) and risk of venous thromboembolism (VTE) in Han and Uyghur population in Xinjiang. Material and method: We conducted a case control study composed of 246 cases, including 86 Uyghur and 160 Han ethnic diagnosed VTE were admitted in the First Affiliated Hospital of Xinjiang Medical University between January 2008 to December 2012, and 292 population including 122 Uyghur ethnic and 170 Han ethnic were studied as controls. To detect the polymorphism of MTHFR gene C677T, A1298T, and C1317T, Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was applied. Fluorescence polarization immunoassay was adopted to determine the plasma levels Homocysteine (Hcy), folic acid and vitaminB12 (VitB12). The association of the polymorphism of MTHFR and levels Hcy, folic acid and VitB12 with VTE was analyzed. Results: The MTHFR gene C677T genotypes distribution in Uyghur VTE patients and control groups were: TT (27.91% vs. 12.29%), CT (41.86% vs. 52.46%) and CC (30.23% vs. 35.25%), respectively; and in Han VTE patients and control groups were: TT (27.49% vs. 14.71%), CT (44.38% vs. 53.53%) and CC (28.13% vs. 31.76%), respectively, and there were significant differences in TT genotype of MTHFRC677T between VTE patients and controls in both Uyghur and Han ethnic (Uyghur: x2=8.070, P=0.005; Han: x2=8.159, P=0.004). However, there were no significant differences in the MTHFR gene A1298T and C1317T genotyping distribution frequency in Uygur and Han ethnic between VTE patients and controls (P>0.05). Plasma levels of Hcy in MTHFR gene TT genotype were statistically higher than CT and CC genotype (P<0.05). After adjusting for age, gender, smoking, hypertension, hyperlipidemia, diabetes and MTHFR genotype for plasma Hcy levels, multifactor logistic regression analysis showed (OR=1.025, 95% CI 1.003-1.046, P=0.024) and obesity (OR=4.660, 95% CI 1.417-15.324, P=0.011) were independent risk factors for Uygur ethnic with VTE while plasma Hcy levels (OR=1.020, 95% CI 1.006-1.034, P=0.004) and smoking (OR=2.867, 95% CI 1.062-6.586, P=0.024) were independent risk factors for Han ethnic with VTE. Conclusions: Our finding supports significant role of MTHFR gene in VTE and evidence of genetically determined HHcy contribute a risk for VTE, and a smoker with tHcy has positive association with a risk of VTE. PMID:26770360

  15. Increased susceptibility to mild neonatal stress in MTHFR deficient mice.

    PubMed

    Kezurer, N; Galron, D; Golan, H M

    2013-09-15

    Early life stress is shown to have a life-span outcome on human and animal behavior, increasing the risk for psychopathology. The gene methylenetetrahydrofolate reductase (MTHFR), which encodes for a key enzyme in one carbon metabolism, shows a high prevalence of polymorphism in patients with developmental disorders. Here we examined the hypothesis that MTHFR deficiency results in an increased susceptibility of the developing brain to mild neonatal stress (NS). Mild NS failed to alter corticosterone levels in young and adult Wt mice. However, an elevated level of corticosterone was found in the MTHFR deficient-NS female, exemplifying enhanced sensitivity to NS. Behavioral phenotyping of Wt and MTHFR deficient mice provides evidence that the effect of mild NS may be amplified by the MTHFR deficient genotype. Distinct behavioral characteristics were altered in male and female mice. In general, three patterns of influence on mice behavior were observed: (1) an additive suppressive effect of NS and MTHFR deficiency on exploration and activity was evident in females; (2) stress related parameters were significantly sensitive to genotype in females, presenting an interaction between genotype and sex; (3) various aspects of behavior in a social setting were modified preferably in males by genotype, NS and the interaction between the two, while females exhibited a smaller effect that was restricted to NS with no genotype effect. Overall, our results support an interaction between mild NS, the MTHFR genotype and sex. We suggest using this animal model to study the molecular mechanism linking these two risk factors and their involvement in neurodevelopmental disorders such as schizophrenia and autism. PMID:23896051

  16. Altered heme catabolism by heme oxygenase-1 caused by mutations in human NADPH cytochrome P450 reductase

    SciTech Connect

    Pandey, Amit V.; Flueck, Christa E.; Mullis, Primus E.

    2010-09-24

    Research highlights: {yields} Mutations in POR identified from patients lead to reduced HO-1 activities. {yields} POR mutation Y181D affecting FMN binding results in total loss of HO-1 activity. {yields} POR mutations A287P, C569Y and V608F, lost 50-70% activity. {yields} Mutations in FAD binding domain, R457H, Y459H and V492E lost all HO-1 activity. {yields} POR polymorphisms P228L, R316W, G413S, A503V and G504R have normal activity. -- Abstract: Human heme oxygenase-1 (HO-1) carries out heme catabolism supported by electrons supplied from the NADPH through NADPH P450 reductase (POR, CPR). Previously we have shown that mutations in human POR cause a rare form of congenital adrenal hyperplasia. In this study, we have evaluated the effects of mutations in POR on HO-1 activity. We used purified preparations of wild type and mutant human POR and in vitro reconstitution with purified HO-1 to measure heme degradation in a coupled assay using biliverdin reductase. Here we show that mutations in POR found in patients may reduce HO-1 activity, potentially influencing heme catabolism in individuals carrying mutant POR alleles. POR mutants Y181D, A457H, Y459H, V492E and R616X had total loss of HO-1 activity, while POR mutations A287P, C569Y and V608F lost 50-70% activity. The POR variants P228L, R316W and G413S, A503V and G504R identified as polymorphs had close to WT activity. Loss of HO-1 activity may result in increased oxidative neurotoxicity, anemia, growth retardation and iron deposition. Further examination of patients affected with POR deficiency will be required to assess the metabolic effects of reduced HO-1 activity in affected individuals.

  17. Congenital Recessive Methemoglobinemia Revealed in Adulthood: Description of a New Mutation in Cytochrome b5 Reductase Gene.

    PubMed

    Forestier, Alexandra; Pissard, Serge; Cretet, Justine; Mambie, Adeline; Pascal, Laurent; Cliquennois, Manuel; Cambier, Nathalie; Rose, Christian

    2015-01-01

    Methemoglobinemia can be acquired (oxidizing drugs or chemicals products) or inherited either by mutations affecting globin chains [M hemoglobins (M Hbs)] or by defects in the enzymatic system involved in the reduction of spontaneous Hb oxidation: nicotinamide adenine dinucleotide (NADH)-cytochrome b5 reductase. It is encoded by the CYB5R3 gene: there are two phenotypes of autosomal recessive congenital methemoglobinemia, in type II CYB5R deficiency is generalized and affects all cells, leading to an early onset, whereas in type I, the enzyme deficiency is restricted to erythrocytes, usually discovered in infancy but not exclusively. We report a new case of methemoglobinemia discovered in a patient from Bahrain who exhibited an unknown dyspnea at the age of 37 years without trigger events or oxidizing products. We discovered a new mutation in the CYB5R3 gene: exon 9, codon 266 (delGAG) (GLU) (CYB5R3: c.726_729delGAG) in the homozygous state. Appearance of methemoglobinemia in an adult usually suggests an acquired cause but our case illustrated that it could also reveal a type I mutation of cytochrome b5 reductase. PMID:26291966

  18. Targeted insertion of two Mthfr promoters in mice reveals temporal- and tissue-specific regulation.

    PubMed

    Pickell, Laura; Wu, Qing; Wang, Xiao-Ling; Leclerc, Daniel; Friedman, Hana; Peterson, Alan C; Rozen, Rima

    2011-12-01

    Methylenetetrahydrofolate reductase (MTHFR), a key enzyme in folate metabolism, synthesizes 5-methyltetrahydrofolate, the main circulatory form of folate which is required for maintaining nontoxic levels of homocysteine and providing one-carbon units for methylation. A common 677C → T variant in MTHFR confers mild MTHFR deficiency and has been associated with a number of human disorders, including neural tube defects and vascular disease. Two promoters of Mthfr, designated as upstream and downstream promoters, are located upstream of a transcription start site cluster and have previously demonstrated cell-specific activities. In this study we used a unique approach for targeted, single-copy transgene insertion to generate transgenic mice carrying a Mthfr upstream or Mthfr downstream promoter-reporter construct located 5' to the endogenous Hprt (hypoxanthine-guanine phosphoribosyltransferase) locus. The Mthfr downstream promoter demonstrated activity in the neural tube, neural crest cells, dorsal root ganglia, heart, and endothelial cells of blood vessels in 10.5-days post coitum embryos and placentas. Upstream promoter activity was absent at this developmental stage. Postnatally, both promoters demonstrated activity in the brain stem, hippocampus, and thalamus of 1-week-old brain that became stronger in the adult. The Mthfr upstream promoter also showed activity in the cerebellum and cerebral cortex. Both promoters were active in male reproductive tissues, including 1-week-old epididymides, and there was upstream promoter-specific activity in the adult testis. Our investigation of Mthfr regulation in an in vivo mouse model revealed temporal- and tissue-specific regulation that supports important roles for MTHFR in the developing embryo, and in postnatal brain and male reproductive tissues. PMID:21769670

  19. Staying green postharvest: how three mutations in the Arabidopsis chlorophyll b reductase gene NYC1 delay degreening by distinct mechanisms.

    PubMed

    Jibran, Rubina; Sullivan, Kerry L; Crowhurst, Ross; Erridge, Zoe A; Chagné, David; McLachlan, Andrew R G; Brummell, David A; Dijkwel, Paul P; Hunter, Donald A

    2015-11-01

    Stresses such as energy deprivation, wounding and water-supply disruption often contribute to rapid deterioration of harvested tissues. To uncover the genetic regulation behind such stresses, a simple assessment system was used to detect senescence mutants in conjunction with two rapid mapping techniques to identify the causal mutations. To demonstrate the power of this approach, immature inflorescences of Arabidopsis plants that contained ethyl methanesulfonate-induced lesions were detached and screened for altered timing of dark-induced senescence. Numerous mutant lines displaying accelerated or delayed timing of senescence relative to wild type were discovered. The underlying mutations in three of these were identified using High Resolution Melting analysis to map to a chromosomal arm followed by a whole-genome sequencing-based mapping method, termed 'Needle in the K-Stack', to identify the causal lesions. All three mutations were single base pair changes and occurred in the same gene, NON-YELLOW COLORING1 (NYC1), a chlorophyll b reductase of the short-chain dehydrogenase/reductase (SDR) superfamily. This was consistent with the mutants preferentially retaining chlorophyll b, although substantial amounts of chlorophyll b were still lost. The single base pair mutations disrupted NYC1 function by three distinct mechanisms, one by producing a termination codon, the second by interfering with correct intron splicing and the third by replacing a highly conserved proline with a non-equivalent serine residue. This non-synonymous amino acid change, which occurred in the NADPH binding domain of NYC1, is the first example of such a mutation in an SDR protein inhibiting a physiological response in plants. PMID:26261268

  20. Genetic and epigenetic variants in the MTHFR gene are not associated with non-Hodgkin lymphoma.

    PubMed

    Bradshaw, Gabrielle; Sutherland, Heidi G; Camilleri, Emily T; Lea, Rodney A; Haupt, Larisa M; Griffiths, Lyn R

    2015-12-01

    The methylenetetrahydrofolate reductase (MTHFR) gene codes for the MTHFR enzyme which plays a key role in the pathway of folate and methionine metabolism. Polymorphisms of genes in this pathway affect its regulation and have been linked to lymphoma. In this study we examined whether we could detect an association between two common non-synonymous MTHFR polymorphisms, 677C > T (rs1801133) and 1298A > C (rs1801131), and susceptibility to non-Hodgkin lymphoma (NHL) in an Australian case-control cohort. We found no significant differences between genotype or allele frequencies for either polymorphisms between lymphoma cases and controls. We also explored whether epigenetic modification of MTHFR, specifically DNA methylation of a CpG island in the MTHFR promoter region, is associated with NHL using blood samples from patients. No difference in methylation levels was detected between the case and control samples suggesting that although hypermethylation of MTHFR has been reported in tumour tissues, particularly in the diffuse large B-cell lymphoma subtype of NHL, methylation of this MTHFR promoter CpG island is not a suitable epigenetic biomarker for NHL diagnosis or prognosis in peripheral blood samples. Further studies into epigenetic variants could focus on genes that are robustly associated with NHL susceptibility. PMID:26629414

  1. Factor V Leiden, factor V Cambridge, factor II GA20210, and methylenetetrahydrofolate reductase in cerebral venous and sinus thrombosis: A case-control study

    PubMed Central

    Saadatnia, Mohammad; Salehi, Mansour; Movahedian, Ahmad; Shariat, Seyed Ziaeddin Samsam; Salari, Mehri; Tajmirriahi, Marzieh; Asadimobarakeh, Elham; Salehi, Rasoul; Amini, Gilda; Ebrahimi, Homa; Kheradmand, Ehsan

    2015-01-01

    Background: Factor V G1691A (FV Leiden), FII GA20210, and methylenetetrahydrofolate reductase (MTHFR) C677T mutations are the most common genetic risk factors for thromboembolism in the Western countries. However, there is rare data in Iran about cerebral venous and sinus thrombosis (CVST) patients. The aim of this study was to evaluate the frequency of common genetic thrombophilic factors in CVST patients. Materials and Methods: Forty consequently CVST patients from two University Hospital in Isfahan University of Medical Sciences aged more than 15 years from January 2009 to January 2011 were recruited. In parallel, 51 healthy subjects with the same age and race from similar population selected as controls. FV Leiden, FII GA20210, MTHFR C677T, and FV Cambridge gene mutations by polymerase chain reaction technique were evaluated in case and control groups. Results: FV Leiden, FII GA20210, and FV Cambridge gene mutations had very low prevalence in both case (5%, 2%, 0%) and control (2.5%, 0%, 0%) and were not found any significant difference between groups. MTHFR C677T mutations was in 22 (55%) of patients in case group and 18 (35.5%) of control group (P = 0.09). Conclusion: This study showed that the prevalence of FV Leiden, FII GA20210, and FV Cambridge were low. Laboratory investigations of these mutations as a routine test for all patients with CVST may not be cost benefit. PMID:26600830

  2. Population- and Family-Based Studies Associate the "MTHFR" Gene with Idiopathic Autism in Simplex Families

    ERIC Educational Resources Information Center

    Liu, Xudong; Solehdin, Fatima; Cohen, Ira L.; Gonzalez, Maripaz G.; Jenkins, Edmund C.; Lewis, M. E. Suzanne; Holden, Jeanette J. A.

    2011-01-01

    Two methylenetetrahydrofolate reductase gene ("MTHFR") functional polymorphisms were studied in 205 North American simplex (SPX) and 307 multiplex (MPX) families having one or more children with an autism spectrum disorder. Case-control comparisons revealed a significantly higher frequency of the low-activity 677T allele, higher prevalence of the

  3. Population- and Family-Based Studies Associate the "MTHFR" Gene with Idiopathic Autism in Simplex Families

    ERIC Educational Resources Information Center

    Liu, Xudong; Solehdin, Fatima; Cohen, Ira L.; Gonzalez, Maripaz G.; Jenkins, Edmund C.; Lewis, M. E. Suzanne; Holden, Jeanette J. A.

    2011-01-01

    Two methylenetetrahydrofolate reductase gene ("MTHFR") functional polymorphisms were studied in 205 North American simplex (SPX) and 307 multiplex (MPX) families having one or more children with an autism spectrum disorder. Case-control comparisons revealed a significantly higher frequency of the low-activity 677T allele, higher prevalence of the…

  4. Coronary heart disease among Circassians in Israel is not associated with mutations in thrombophilia genes.

    PubMed

    Falik-Zaccai, Tzipora C; Haron, Yafa; Eilat, Danny; Harash, Bakky; Golinker, Ekaterina; Hussein, Osamah; Eisikovits, Rivka; Borochowitz, Zvi; Linn, Shai

    2003-02-01

    The Muslim Circassian community in Israel represents a unique ethnic community that has never been genetically and medically studied. One hundred and fifty-three randomly selected individuals (91 men and 62 women, ages 35 and older), both healthy or with a history of cardiovascular disease (14 men and 7 women), were studied in a cross-sectional descriptive study for mutations in three genes known to be associated with hypercoagulation. Their medical records were reviewed for risk factors and history of cardiovascular disease (CVD) and thromboembolic events. The mutation FV 1691G --> A in the gene for factor V (FV 1691G --> A), the mutation MTHFR 677C --> T in the gene 5,10-methylenetetrahydrofolate reductase, and the allele G20210A in the gene for prothrombin (PT 20210G --> A) were studied. The mutation FV 1691G --> A was observed in a heterozygous form in 1.3% of 153 studied individuals, while the PT 20210G --> A allele was identified in a heterozygous form in 6.5%. No individual was found homozygous for either of these two mutations. The MTHFR C677T mutation was present in 42.8% of the studied population in a heterozygous form and in 8.6% in a homozygous form. Serum homocysteine, folate, and B12 levels were studied among individuals heterozygous and homozygous for the MTHFR C677T mutation. There was no significant difference in the prevalence of all three mutations between individuals affected with CVD or other forms of thromboembolic disease and healthy individuals. This is the first report of a medical condition and its genetic background among Circassians. The high prevalence of CVD among Circassians was found to be etiologically unrelated to the three mutations studied in the genes for factor V, MTHFR, and prothrombin. PMID:12713146

  5. A mutation in Arabidopsis cytochrome b5 reductase identified by high-throughput screening differentially affects hydroxylation and desaturation.

    PubMed

    Kumar, Rajesh; Wallis, James G; Skidmore, Chris; Browse, John

    2006-12-01

    As a model for analyzing the production of novel fatty acids in oilseeds, we used the genetic and molecular techniques available for Arabidopsis to characterize modifying mutations affecting the accumulation of hydroxy fatty acids in the seeds of Arabidopsis plants that express a transgene for the castor bean fatty acid hydroxylase, FAH12. We developed a high-throughput analytical system and used it to identify three complementation classes of mutations with reduced hydroxy fatty acid accumulation from among Arabidopsis M3 seed samples derived from chemical mutagenesis. We identified one of the mutations by positional cloning as a single base pair change in a gene encoding NADH:cytochrome b5 reductase (CBR1, At5g17770). When expressed in yeast, the mutant form of the enzyme was less active and less stable than the wild-type enzyme. Characterization of homozygous mutant lines with and without the FAH12 transgene (FAH12 cbr1-1 and cbr1-1, respectively) indicated that the only detectable consequence of the cbr1-1 mutation was on desaturase and hydroxylase reactions in the developing seed. The leaf and root fatty compositions, as well as the growth, development and seed production of mutant plants were indistinguishable from wild type. Interestingly, while the cbr1-1 mutation reduced the accumulation of hydroxy fatty acids in seeds by 85%, the effects on 18:1 and 18:2 desaturation reactions were much less (<25% and <60%, respectively). These results suggest that there is competition in developing seeds among the several reactions that utilize reduced cytochrome b5. PMID:17227547

  6. 5,10 Methylenetetrahydrofolate reductase genetic polymorphism as a risk factor for neural tube defects

    SciTech Connect

    Ou, C.Y.; Brown, V.K.; Khoury, M.J.

    1996-06-28

    Persons with a thermolabile form of the enzyme 5,10 methylenetetrahydrofolate reductase (MTHFR) have reduced enzyme activity and increased plasma homocysteine which can be lowered by supplemental folic acid. Thermolability of the enzyme has recently been shown to be caused by a common mutation (677C{sup {r_arrow}}T) in the MTHFR gene. We studied 41 fibroblast cultures from NTD-affected fetuses and compared their genotypes with those of 109 blood specimens from individuals in the general population. 677C{sup {r_arrow}}T homozygosity was associated with a 7.2 fold increased risk for NTDs (95% confidence interval: 1.8-30.3; p value: 0.001). These preliminary data suggest that the 677C{sup {r_arrow}}T polymorphism of the MTHFR gene is a risk factor for spina bifida and anencephaly that may provide a partial biologic explanation for why folic acid prevents these types of NTD. 13 refs., 1 fig., 1 tab.

  7. Association of the MTHFR A1298C variant with unexplained severe male infertility.

    PubMed

    Eloualid, Abdelmajid; Abidi, Omar; Charif, Majida; El Houate, Brahim; Benrahma, Houda; Louanjli, Noureddine; Chadli, Elbakkay; Ajjemami, Maria; Barakat, Abdelhamid; Bashamboo, Anu; McElreavey, Ken; Rhaissi, Houria; Rouba, Hassan

    2012-01-01

    The methylenetetrahydrofolate reductase (MTHFR) gene is one of the main regulatory enzymes involved in folate metabolism, DNA synthesis and remethylation reactions. The influence of MTHFR variants on male infertility is not completely understood. The objective of this study was to analyze the distribution of the MTHFR C677T and A1298C variants using PCR-Restriction Fragment Length Polymorphism (RFLP) in a case group consisting of 344 men with unexplained reduced sperm counts compared to 617 ancestry-matched fertile or normozoospermic controls. The Chi square test was used to analyze the genotype distributions of MTHFR polymorphisms. Our data indicated a lack of association of the C677T variant with infertility. However, the homozygous (C/C) A1298C polymorphism of the MTHFR gene was present at a statistically high significance in severe oligozoospermia group compared with controls (OR?=?3.372, 95% confidence interval CI?=?1.27-8.238; p?=?0.01431). The genotype distribution of the A1298C variants showed significant deviation from the expected Hardy-Weinberg equilibrium, suggesting that purifying selection may be acting on the 1298CC genotype. Further studies are necessary to determine the influence of the environment, especially the consumption of diet folate on sperm counts of men with different MTHFR variants. PMID:22457816

  8. Genetic variations in MTHFR and gastric cardia adenocarcinoma susceptibility in the Chinese Han population

    PubMed Central

    Wang, Yafeng; Chen, Shuchen; Kang, Mingqiang; Tang, Weifeng; Gu, Haiyong; Yin, Jun; Huang, Ziyang

    2015-01-01

    Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms are associated with many types of cancers. The purpose of our study was to evaluate the effect of MTHFR single nucleotide polymorphisms (SNPs) on gastric cardia adenocarcinoma (GCA). We conducted a hospital-based case-control study. Three hundred and thirty cases with GCA and 608 controls were recruited. The ligation detection reaction (LDR) method was used to determine genotypes. The genotype MTHFR rs1801133 TT was significantly more frequent in cases than in controls (adjusted odds ratio (OR) = 1.46, 95% confidence interval (CI) = 1.04-2.05, P = 0.029) in a recessive model, after adjusting for age, sex and smoking and alcohol use. The haplotype MTHFR Grs4845882Ars4846048Trs1801133Crs9651118Ars3753584 was more frequent in cases than in controls (crude OR = 5.32, 95% CI = 2.34-12.10, P < 0.001). No association between other genotypes and haplotypes was observed. Our results suggest that the genotype MTHFR rs1801133 TT and the MTHFR Grs4845882Ars4846048Trs1801133Crs9651118Ars3753584 haplotype may be associated with susceptibility to GCA. Further studies are needed to confirm these findings. PMID:26770518

  9. MTHFR genotype and colorectal adenoma recurrence: data from a double blind placebo controlled clinical trial

    PubMed Central

    Levine, A. Joan; Wallace, Kristin; Tsang, Shirley; Haile, Robert W.; Saibil, Fred; Ahnen, Dennis; Cole, Bernard F.; Barry, Elizabeth L.; Munroe, David J; Ali, Iqbal U; Ueland, Per; Baron, John A.

    2009-01-01

    Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in folate metabolism. We ssessed the association between two common MTHFR variants, 677C>T and 1298A>C, and adenoma recurrence in the context of a randomized double blind clinical trial of aspirin use and folate supplementation. We used generalized linear regression to estimate risk ratios and 95% CIs for recurrence, adjusting for age, sex, clinical center, follow-up time, and treatment status. Neither MTHFR polymorphism was associated with overall or advanced adenoma recurrence. Compared to those with 2 wild type alleles, the relative risk for advanced adenoma was 0.75 (95% CI 0.36 to 1.55), for the MTHFR 677 TT genotype and 1.16 (95% CI 0.582.33) for the MTHFR 1298 CC genotype. The effect of folate supplementation on recurrence risk did not differ by genotype. Our findings indicate that MTHFR genotype does not change adenoma risk in a manner similar to its effect on colorectal cancer, and does not modify the effect of folate supplementation on metachronous adenoma risk. PMID:18768511

  10. Association of the MTHFR A1298C Variant with Unexplained Severe Male Infertility

    PubMed Central

    Eloualid, Abdelmajid; Abidi, Omar; Charif, Majida; El houate, Brahim; Benrahma, Houda; Louanjli, Noureddine; Chadli, Elbakkay; Ajjemami, Maria; Barakat, Abdelhamid; Bashamboo, Anu; McElreavey, Ken; Rhaissi, Houria; Rouba, Hassan

    2012-01-01

    The methylenetetrahydrofolate reductase (MTHFR) gene is one of the main regulatory enzymes involved in folate metabolism, DNA synthesis and remethylation reactions. The influence of MTHFR variants on male infertility is not completely understood. The objective of this study was to analyze the distribution of the MTHFR C677T and A1298C variants using PCR-Restriction Fragment Length Polymorphism (RFLP) in a case group consisting of 344 men with unexplained reduced sperm counts compared to 617 ancestry-matched fertile or normozoospermic controls. The Chi square test was used to analyze the genotype distributions of MTHFR polymorphisms. Our data indicated a lack of association of the C677T variant with infertility. However, the homozygous (C/C) A1298C polymorphism of the MTHFR gene was present at a statistically high significance in severe oligozoospermia group compared with controls (OR?=?3.372, 95% confidence interval CI?=?1.278.238; p?=?0.01431). The genotype distribution of the A1298C variants showed significant deviation from the expected Hardy-Weinberg equilibrium, suggesting that purifying selection may be acting on the 1298CC genotype. Further studies are necessary to determine the influence of the environment, especially the consumption of diet folate on sperm counts of men with different MTHFR variants. PMID:22457816

  11. Hyperhomocysteinemia and the compound heterozygous state for methylene tetrahydrofolate reductase are independent risk factors for deep vein thrombosis among South Indians.

    PubMed

    Naushad, Sm; Jamal, Nurul Jain; Angalena, R; Prasad, C Krishna; Devi, A Radha Rama

    2007-03-01

    To investigate the role of methylene tetrahydrofolate reductase (MTHFR) (677 C-->T and 1298 A-->C), factor V (1691 G-->A), factor II (20210 G-->A) genetic polymorphisms and hyperhomocysteinemia in the aetiology of deep vein thrombosis (DVT) in 163 cases and 163 controls. Polymerase chain reaction-restriction fragment length polymorphism was used for genotyping, reverse-phase high-performance liquid chromatography for plasma homocysteine, and Student's t-test and Fisher exact tests were used for statistical analysis. Elevated mean plasma homocysteine levels were observed in DVT cases irrespective of gender differences. Homocysteine elevation above the 95th percentile of the control group associated with 9.4-fold and 7.6-fold increased risk for DVT in men and women, respectively. Genotyping showed the MTHFR 677CT/1298AC genotype (i.e. compound heterozygosity) is associated with 3.5-fold risk for thrombosis. The factor V Leiden mutation frequency was higher in DVT cases, but not statistically significant; however, genetic predisposition to this mutation was associated with early age of DVT onset. Factor II mutation was absent in cases and controls. Co-segregation of two or more risk factors was associated with 11.7-fold increased risk for thrombosis. This study projects that hyperhomocysteinemia and compound heterozygous state for MTHFR are independent risk factors for DVT among South Indians. PMID:17287626

  12. Role of folate status and methylenetetrahydrofolate reductase genotype on the toxicity and outcome of induction chemotherapy in children with acute lymphoblastic leukemia.

    PubMed

    Roy Moulik, Nirmalya; Kumar, Archana; Agrawal, Suraksha; Awasthi, Shally; Mahdi, Abbas Ali; Kumar, Ashutosh

    2015-05-01

    The effect of serum folate levels and methylenetetrahydrofolate reductase (MTHFR) genotype on complications and outcome of induction chemotherapy in 150 children with acute lymphoblastic leukemia (ALL) was studied. Folate deficiency in 26% at baseline was more common in children with MTHFR 677 mutations. Folate deficient children had a higher incidence of neutropenia (p = 0.03), thrombocytopenia (p = 0.02) and febrile neutropenia (p = 0.01) and higher transfusion requirement during induction compared to folate sufficient children. Sepsis related induction deaths were more frequent in folate deficient children (p = 0.02) during induction. Children with 677 and 1298 mutations had a higher incidence of cytopenias (p = 0.01) and mucositis (p = 0.007), the risks of which increased with concomitant folate deficiency. A significant fall in folate levels was observed post-induction (p = 0.02), most markedly in mutant 677 genotypes. Multivariate analysis revealed associations of baseline folate deficiency with low counts at day 14 (p = 0.001) and MTHFR 1298 mutations with mucositis (p = 0.02). PMID:25065700

  13. Quantitative assessment of the association between MTHFR rs1801131 polymorphism and risk of liver cancer.

    PubMed

    Liang, Tie-Jun; Liu, Hui; Zhao, Xiao-Qian; Tan, Yan-Rong; Jing, Kai; Qin, Cheng-Yong

    2014-01-01

    Methylenetetrahydrofolate reductase (MTHFR) is one of the most important enzymes for folate metabolism which plays a key role in cell metabolism. MTHFR rs1801131 (A1298C) polymorphism can decrease in vitro MTHFR enzyme activity and has been hypothesized to be associated with liver cancer risk. This study aimed to quantify the strength of the association between MTHFR rs1801131 polymorphism and liver cancer risk by performing a meta-analysis. We searched the PubMed and Wanfang databases for studies relating on the association between MTHFR rs1801131 polymorphism and risk of liver cancer. Seven studies with 2,030 cases of liver cancer and 3,096 controls were finally included into the meta-analysis. Meta-analysis of a total of seven studies showed that the homozygote genotype CC of MTHFR rs1801131 polymorphism was significantly associated with decreased risk of liver cancer (for CC versus AA: odds ratio (OR)?=?0.65, 95% confidence interval (CI) 0.47-0.89, P?=?0.007; for CC versus AA?+?AC: OR?=?0.65, 95% CI 0.48-0.89, P?=?0.006). Subgroup by race showed that the homozygote genotype CC of MTHFR rs1801131 polymorphism was significantly associated with decreased risk of liver cancer in Asians (CC versus AA: OR?=?0.64, 95% CI 0.46-0.90, P?=?0.010; for CC versus AA?+ AC: OR?=?0.63, 95% CI 0.45-0.88, P?=?0.007). However, the association in Caucasians was still unclear owing to the limited data available now. Thus, Asian individuals with the homozygote genotype CC of MTHFR rs1801131 polymorphism are significantly associated with decreased risk of liver cancer. The association in Caucasians needs further studies. PMID:24014085

  14. Plasma homocysteine levels correlated to interactions between folate status and methylene tetrahydrofolate reductase gene mutation in women with unexplained recurrent pregnancy loss.

    PubMed

    Kumar, K S D; Govindaiah, V; Naushad, S E; Devi, R R; Jyothy, A

    2003-01-01

    Hyperhomocysteinaemia, a risk factor for recurrent pregnancy loss, is related either to a hereditary defect within the methionine-homocysteine pathway or it might be acquired as a result of deficiencies of vitamin B(12) and folate (B(9)). Because hyperhomocysteinaemia seems to be determined by both genetic and environmental factors, the current study was undertaken to find out the interactions between folate status and MTHFR mutation on the homocysteine concentration in 24 women experiencing unexplained three or more consecutive recurrent pregnancy losses. The median fasting total plasma homocysteine concentration in the study group was 10.23 micro mol/l compared to 8.95 micro mol/l; P = 0.096 in the controls. Elevated homocysteine levels > 18 micro mol/l, which was considered to be a risk factor for recurrent early pregnancy loss, was found in four women in the study group and none among the controls. Lower red cell folate levels (normal range >/= 160 ng/ml) were observed in nine (37.5%) women among the study group, compared to five (20.84%) women among controls. The mean +/- SD red cell folate levels in the study group was found to be 154.37 +/- 37.07, while in the controls it was 159.0 +/- 28.97. In the present study six women in the study group and two among controls were found to be carriers for the C677T MTHFR mutation. None were homozygous for the mutant (TT) allele. The highest values of homocysteine concentration were found in women experiencing recurrent pregnancy loss with both the CT genotype and folate deficiency. Identification of hyperhomocysteinaemia in women with recurrent pregnancy loss may help in therapeutic normalisation and might permit a normal birth. PMID:12623486

  15. Methylenetetrahydrofolate reductase gene polymorphisms in 13 Chinese ethnic populations.

    PubMed

    Mao, Renfang; Fan, Yihui; Chen, Feng; Sun, Donglin; Bai, Jing; Fu, Songbin

    2008-04-01

    It has been shown that the polymorphisms of Methylenetetrahydrofolate reductase (MTHFR) gene are associated with susceptibility to several disorders including hyperhomocysteinemia, vascular disease, birth defect, and certain cancers, and exhibit great diversities among various populations. The aim of this study was to investigate the prevalence of two common non-synonymous single nucleotide polymorphisms (i.e., C677T and A1298C) at MTHFR gene in 13 Chinese populations. A total of 1015 healthy individuals from 13 populations distributed widely from north to south in China were studied. DNA samples were isolated from peripheral blood samples and genotyped using polymerase chain reaction-restriction fragment length polymorphism. For C677T polymorphism, the frequency in Chinese of CC homozygous was 42.4%; CT heterozygous was 49.8%; and TT homozygous was 7.9%. For A1298C, AA homozygous was 39.2%; AC heterozygous was 38.6%; and CC homozygous was 22.2%. The allelic frequency of 677T and 1298C was 32.8 and 41.5%, respectively, and each allele frequency had significant variance in 13 Chinese populations. The frequency of the 677T allele among southern populations was 30.7% compared to 38.0% among northeastern and 30.5% among northwestern populations. The difference was statistically significant (p < 0.01). The frequency of 1298C mutation in southerns was 58.9% whereas in northeasterns it was 24.0% and 37.6% in northwesterns. This was also statistically significant (p < 0.01). The MTHFR C677T and A1298C sites were in linkage disequilibrium in the Chinese population revealed by our data. PMID:18098118

  16. Domain swing upon His to Ala mutation in nitrite reductase of Pseudomonas aeruginosa.

    PubMed

    Brown, K; Roig-Zamboni, V; Cutruzzola', F; Arese, M; Sun, W; Brunori, M; Cambillau, C; Tegoni, M

    2001-09-21

    The nitrite reductase (NIR) from Pseudomonas aeruginosa (NIR-Pa) is a soluble enzyme catalysing the reduction of nitrite (NO2(-)) to nitric oxide (NO). The enzyme is a 120 kDa homodimer, in which the monomers carry a c-heme domain and a d(1)-heme domain. The structures of the enzyme in both the oxidised and reduced state were solved previously and indicate His327 and His369 as putative catalytic residues. The kinetic characterisation of site-directed mutants has shown that the substitution of either one of these two His with Ala dramatically reduces the physiologically relevant reactivity towards nitrite, leaving the reactivity towards oxygen unaffected. The three-dimensional structures of P. aeruginosa NIR mutant H327A, and H369A in complex with NO have been solved by multiple wavelength anomalous dispersion (MAD), using the iron anomalous signal, and molecular replacement techniques. In both refined crystal structures the c-heme domain, whilst preserving its classical c-type cytochrome fold, has undergone a 60 degrees rigid-body rotation around an axis parallel with the pseudo 8-fold axis of the beta-propeller, and passing through residue Gln115. Even though the distance between the Fe ions of the c and d(1)-heme remains 21 A, the edge-to-edge distance between the two hemes has increased by 5 A. Furthermore the distal side of the d(1)-heme pocket appears to have undergone structural re-arrangement and Tyr10 has moved out of the active site. In the H369A-NO complex, the position and orientation of NO is significantly different from that of the NO bound to the reduced wild-type structure. Our results provide insight into the flexibility of the enzyme and the distinction between nitrite and oxidase reduction mechanisms. Moreover they demonstrate that the two histidine residues play a crucial role in the physiological activity of nitrite reduction, ligand binding and in the structural organisation of nitrite reductase from P. aeruginosa. PMID:11563915

  17. Frequency of the Asn-108 and Thr-108 point mutations in the dihydrofolate reductase gene in Plasmodium falciparum from southwest Colombia.

    PubMed

    Giraldo, L E; Acosta, M C; Labrada, L A; Praba, A; Montenegro-James, S; Saravia, N G; Krogstad, D J

    1998-07-01

    Several point mutations in the dihydrofolate reductase (DHFR) gene of Plasmodium falciparum have been correlated with in vitro anti-folate drug resistance of laboratory and field isolates. Furthermore, two different point mutations that generate amino acid substitutions at the same position of the enzyme have been observed in all the isolates studied to date. These point mutations change a serine (Ser-108) in the wild type to an asparagine (Asn-108 mutation) or to a threonine (Thr-108 mutation). Using the polymerase chain reaction (PCR), it is possible to identify isolates that present these mutations. We used a mutation-specific PCR to screen 71 samples from several geographic locations of Colombia for the Asn-108 mutation (pyrimethamine resistance). In this initial screening 53 of 71 yielded amplification product with the DHFR mutation-specific primers. We further analyzed the 18 samples that did not amplify using a mutation-specific nested PCR. Of those 18 samples, seven amplified with primers specific for the Thr-108 mutation (proguanil resistance), one with the wild type (Ser-108), and 10 did not amplify. Of these 10 samples, three were identified as P. falciparum using a species-specific diagnostic nested PCR base on sequences from the small ribosomal RNA subunit gene. Overall, 51.6% of the samples amplified for the Asn-108 mutation, 10.9% for the Thr-108 mutation, 35.9% with the wild type specific primer, and 4.8% did not amplify with any of the DHFR primers. We observed variability in the frequency of the mutation between the different geographic location. The frequency of the Asn-108 and Thr-108 mutations in the state of Narifio was 25% each, while in Valle del Cauca the frequencies were 59% and 11%, respectively. These results contrast with observations in Brazil in which the Asn-108 mutation was found in 90% of the blood samples screened. PMID:9684639

  18. Pneumocystis jirovecii infection and the associated dihydropteroate synthase (DHPS) and dihydrofolate reductase (DHFR) mutations in HIV-positive individuals from Pune, India.

    PubMed

    Mane, Arati; Gujar, Pankaj; Chandra, Jipsi; Lokhande, Rahul; Dhamgaye, Tilak; Ghorpade, Shivhari; Risbud, Arun

    2015-02-01

    The present study was undertaken to detect Pneumocystis jirovecii infection among HIV-positive patients presenting with symptoms of lower respiratory tract infection and analyze the associated dihydropteroate synthase (DHPS) and dihydrofolate reductase (DHFR) mutations. P. jirovecii infection was detected in 12.6% cases. We did not find DHPS gene mutations at the commonest positions of codon 55 and 57; however, mutation at codon 171 was detected in two cases. No mutations in DHFR gene were detected. The results indicate low prevalence of DHPS and DHFR mutations in Indian P. jirovecii isolates, suggesting that the selective pressure of sulfa drugs on the local strains has probably not reached the levels found in developed nations. PMID:25266324

  19. Targeted Mutations of Bacillus anthracis Dihydrofolate Reductase Condense Complex Structure-Activity Relationships

    SciTech Connect

    J Beierlein; N Karri; A Anderson

    2011-12-31

    Several antifolates, including trimethoprim (TMP) and a series of propargyl-linked analogues, bind dihydrofolate reductase from Bacillus anthracis (BaDHFR) with lower affinity than is typical in other bacterial species. To guide lead optimization for BaDHFR, we explored a new approach to determine structure-activity relationships whereby the enzyme is altered and the analogues remain constant, essentially reversing the standard experimental design. Active site mutants of the enzyme, Ba(F96I)DHFR and Ba(Y102F)DHFR, were created and evaluated with enzyme inhibition assays and crystal structures. The affinities of the antifolates increase up to 60-fold with the Y102F mutant, suggesting that interactions with Tyr 102 are critical for affinity. Crystal structures of the enzymes bound to TMP and propargyl-linked inhibitors reveal the basis of TMP resistance and illuminate the influence of Tyr 102 on the lipophilic linker between the pyrimidine and aryl rings. Two new inhibitors test and validate these conclusions and show the value of the technique for providing new directions during lead optimization.

  20. Population- and family-based studies associate the MTHFR gene with idiopathic autism in simplex families.

    PubMed

    Liu, Xudong; Solehdin, Fatima; Cohen, Ira L; Gonzalez, Maripaz G; Jenkins, Edmund C; Lewis, M E Suzanne; Holden, Jeanette J A

    2011-07-01

    Two methylenetetrahydrofolate reductase gene (MTHFR) functional polymorphisms were studied in 205 North American simplex (SPX) and 307 multiplex (MPX) families having one or more children with an autism spectrum disorder. Case-control comparisons revealed a significantly higher frequency of the low-activity 677T allele, higher prevalence of the 677TT genotype and higher frequencies of the 677T-1298A haplotype and double homozygous 677TT/1298AA genotype in affected individuals relative to controls. Family-based association testing demonstrated significant preferential transmission of the 677T and 1298A alleles and the 677T-1298A haplotype to affected offspring. The results were not replicated in MPX families. The results associate the MTHFR gene with autism in SPX families only, suggesting that reduced MTHFR activity is a risk factor for autism in these families. PMID:21069446

  1. Geographical and Ethnic Distributions of the MTHFR C677T, A1298C and MTRR A66G Gene Polymorphisms in Chinese Populations: A Meta-Analysis

    PubMed Central

    Zeng, Dingyuan

    2016-01-01

    Background The geographical and ethnic distributions of the polymorphic methylenetetrahydrofolate reductase (MTHFR) mutations (C677T and A1298C) and methionine synthase reductase (MTRR) mutation (A66G) remain heterogeneous in China. The goal of this study was to estimate the pooled frequencies of the alleles and associated genotypes of these gene polymorphisms among healthy populations in Mainland China. Objective and Methods We systematically reviewed published epidemiological studies on the distributions of 3 genetic variants in Chinese healthy populations living in Mainland China through a meta-analysis. The relevant electronic databases were searched. All of the raw data of the eligible citations were extracted. The frequency estimates were stratified by geography, ethnicity and sex. Results Sixty-six studies were identified with a total of 92277 study participants. The meta-analysis revealed that the frequencies of the MTHFR C677T, A1298C, and MTRR A66G gene polymorphisms varied significantly between different ethnic groups and along geographical gradients. The frequencies of the 677T allele and 677TT genotype increased along the southern-central-northern direction across Mainland China (all Pvalues≤0.001). The frequencies of the 1298C, 1298CC, 66G and 66GG genotypes decreased along the south-central-north direction across the country (all Pvalues≤0.001). Conclusions Our meta-analysis strongly indicates significant geographical and ethnic variations in the frequencies of the C677T, A1298C, and A66G gene polymorphisms in the folate metabolism pathway among Chinese populations. PMID:27089387

  2. Steroid Biomarkers and Genetic Studies Reveal Inactivating Mutations in Hexose-6-Phosphate Dehydrogenase in Patients with Cortisone Reductase Deficiency

    PubMed Central

    Lavery, Gareth G.; Walker, Elizabeth A.; Tiganescu, Ana; Ride, Jon P.; Shackleton, Cedric H. L.; Tomlinson, Jeremy W.; Connell, John M. C.; Ray, David W.; Biason-Lauber, Anna; Malunowicz, Ewa M.; Arlt, Wiebke; Stewart, Paul M.

    2008-01-01

    Context: Cortisone reductase deficiency (CRD) is characterized by a failure to regenerate cortisol from cortisone via 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), resulting in increased cortisol clearance, activation of the hypothalamic-pituitary-axis (HPA) and ACTH-mediated adrenal androgen excess. 11β-HSD1 oxoreductase activity requires the reduced nicotinamide adenine dinucleotide phosphate-generating enzyme hexose-6-phosphate dehydrogenase (H6PDH) within the endoplasmic reticulum. CRD manifests with hyperandrogenism resulting in hirsutism, oligo-amenorrhea, and infertility in females and premature pseudopuberty in males. Recent association studies have failed to corroborate findings that polymorphisms in the genes encoding H6PDH (R453Q) and 11β-HSD1 (Intron 3 inserted adenine) interact to cause CRD. Objective: Our objective was to reevaluate the genetics and steroid biochemistry of patients with CRD. Design: We analyzed 24-h urine collection for steroid biomarkers by gas chromatography/mass spectrometry and sequenced the HSD11B1 and H6PD genes in our CRD cohort. Patients: Patients included four cases presenting with hyperandrogenism and biochemical features clearly indicative of CRD. Results: Gas chromatography/mass spectrometry identified steroid biomarkers that correlated with CRD in each case. Three cases were identified as homozygous (R109AfsX3, Y316X, and G359D) and one case identified as compound heterozygous (c.960G→A and D620fsX3) for mutations in H6PD. No mutations affecting enzyme activity were identified in the HSD11B1 gene. Expression and activity assays demonstrate loss of function for all reported H6PDH mutations. Conclusions: CRD is caused by inactivating mutations in the H6PD gene, rendering the 11β-HSD1 enzyme unable to operate as an oxoreductase, preventing local glucocorticoid regeneration. These data highlight the importance of the redox control of cortisol metabolism and the 11β-HSD1-H6PDH pathway in regulating hypothalamic-pituitary-adrenal axis activity. PMID:18628520

  3. A New Strategy to Produce a Defensin: Stable Production of Mutated NP-1 in Nitrate Reductase-Deficient Chlorella ellipsoidea

    PubMed Central

    Chen, Yu-Hong; Niu, Li-Li; Sun, Yong-Ru; Zhao, Shi-Min; Yang, Fu-Quan; Wang, Richard R.-C.; Wu, Qing; Zhang, Xiang-Qi; Hu, Zan-Min

    2013-01-01

    Defensins are small cationic peptides that could be used as the potential substitute for antibiotics. However, there is no efficient method for producing defensins. In this study, we developed a new strategy to produce defensin in nitrate reductase (NR)-deficient C. ellipsoidea (nrm-4). We constructed a plant expression vector carrying mutated NP-1 gene (mNP-1), a mature α-defensin NP-1 gene from rabbit with an additional initiator codon in the 5′-terminus, in which the selection markers were NptII and NR genes. We transferred mNP-1 into nrm-4 using electroporation and obtained many transgenic lines with high efficiency under selection chemicals G418 and NaNO3. The mNP-1 was characterized using N-terminal sequencing after being isolated from transgenic lines. Excitingly, mNP-1 was produced at high levels (approximately 11.42 mg/l) even after 15 generations of continuous fermentation. In addition, mNP-1 had strong activity against Escherichia coli at 5 µg/ml. This research developed a new method for producing defensins using genetic engineering. PMID:23383016

  4. Mutations in PYCR2, Encoding Pyrroline-5-Carboxylate Reductase 2, Cause Microcephaly and Hypomyelination.

    PubMed

    Nakayama, Tojo; Al-Maawali, Almundher; El-Quessny, Malak; Rajab, Anna; Khalil, Samir; Stoler, Joan M; Tan, Wen-Hann; Nasir, Ramzi; Schmitz-Abe, Klaus; Hill, R Sean; Partlow, Jennifer N; Al-Saffar, Muna; Servattalab, Sarah; LaCoursiere, Christopher M; Tambunan, Dimira E; Coulter, Michael E; Elhosary, Princess C; Gorski, Grzegorz; Barkovich, A James; Markianos, Kyriacos; Poduri, Annapurna; Mochida, Ganeshwaran H

    2015-05-01

    Despite recent advances in understanding the genetic bases of microcephaly, a large number of cases of microcephaly remain unexplained, suggesting that many microcephaly syndromes and associated genes have yet to be identified. Here, we report mutations in PYCR2, which encodes an enzyme in the proline biosynthesis pathway, as the cause of a unique syndrome characterized by postnatal microcephaly, hypomyelination, and reduced cerebral white-matter volume. Linkage mapping and whole-exome sequencing identified homozygous mutations (c.355C>T [p.Arg119Cys] and c.751C>T [p.Arg251Cys]) in PYCR2 in the affected individuals of two consanguineous families. A lymphoblastoid cell line from one affected individual showed a strong reduction in the amount of PYCR2. When mutant cDNAs were transfected into HEK293FT cells, both variant proteins retained normal mitochondrial localization but had lower amounts than the wild-type protein, suggesting that the variant proteins were less stable. A PYCR2-deficient HEK293FT cell line generated by genome editing with the clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9 system showed that PYCR2 loss of function led to decreased mitochondrial membrane potential and increased susceptibility to apoptosis under oxidative stress. Morpholino-based knockdown of a zebrafish PYCR2 ortholog, pycr1b, recapitulated the human microcephaly phenotype, which was rescued by wild-type human PYCR2 mRNA, but not by mutant mRNAs, further supporting the pathogenicity of the identified variants. Hypomyelination and the absence of lax, wrinkly skin distinguishes this condition from that caused by previously reported mutations in the gene encoding PYCR2's isozyme, PYCR1, suggesting a unique and indispensable role for PYCR2 in the human CNS during development. PMID:25865492

  5. Mutations in PYCR2, Encoding Pyrroline-5-Carboxylate Reductase 2, Cause Microcephaly and Hypomyelination

    PubMed Central

    Nakayama, Tojo; Al-Maawali, Almundher; El-Quessny, Malak; Rajab, Anna; Khalil, Samir; Stoler, Joan M.; Tan, Wen-Hann; Nasir, Ramzi; Schmitz-Abe, Klaus; Hill, R. Sean; Partlow, Jennifer N.; Al-Saffar, Muna; Servattalab, Sarah; LaCoursiere, Christopher M.; Tambunan, Dimira E.; Coulter, Michael E.; Elhosary, Princess C.; Gorski, Grzegorz; Barkovich, A. James; Markianos, Kyriacos; Poduri, Annapurna; Mochida, Ganeshwaran H.

    2015-01-01

    Despite recent advances in understanding the genetic bases of microcephaly, a large number of cases of microcephaly remain unexplained, suggesting that many microcephaly syndromes and associated genes have yet to be identified. Here, we report mutations in PYCR2, which encodes an enzyme in the proline biosynthesis pathway, as the cause of a unique syndrome characterized by postnatal microcephaly, hypomyelination, and reduced cerebral white-matter volume. Linkage mapping and whole-exome sequencing identified homozygous mutations (c.355C>T [p.Arg119Cys] and c.751C>T [p.Arg251Cys]) in PYCR2 in the affected individuals of two consanguineous families. A lymphoblastoid cell line from one affected individual showed a strong reduction in the amount of PYCR2. When mutant cDNAs were transfected into HEK293FT cells, both variant proteins retained normal mitochondrial localization but had lower amounts than the wild-type protein, suggesting that the variant proteins were less stable. A PYCR2-deficient HEK293FT cell line generated by genome editing with the clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9 system showed that PYCR2 loss of function led to decreased mitochondrial membrane potential and increased susceptibility to apoptosis under oxidative stress. Morpholino-based knockdown of a zebrafish PYCR2 ortholog, pycr1b, recapitulated the human microcephaly phenotype, which was rescued by wild-type human PYCR2 mRNA, but not by mutant mRNAs, further supporting the pathogenicity of the identified variants. Hypomyelination and the absence of lax, wrinkly skin distinguishes this condition from that caused by previously reported mutations in the gene encoding PYCR2’s isozyme, PYCR1, suggesting a unique and indispensable role for PYCR2 in the human CNS during development. PMID:25865492

  6. The MET13 Methylenetetrahydrofolate Reductase Gene Is Essential for Infection-Related Morphogenesis in the Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    Wang, Hong; Wang, Congcong; Li, Ya; Yue, Xiaofeng; Ma, Zhonghua; Talbot, Nicholas J.; Wang, Zhengyi

    2013-01-01

    Methylenetetrahydrofolate reductases (MTHFRs) play a key role in the biosynthesis of methionine in both prokaryotic and eukaryotic organisms. In this study, we report the identification of a novel T-DNA-tagged mutant WH672 in the rice blast fungus Magnaporthe oryzae, which was defective in vegetative growth, conidiation and pathogenicity. Analysis of the mutation confirmed a single T-DNA insertion upstream of MET13, which encodes a 626-amino-acid protein encoding a MTHFR. Targeted gene deletion of MET13 resulted in mutants that were non-pathogenic and significantly impaired in aerial growth and melanin pigmentation. All phenotypes associated with Δmet13 mutants could be overcome by addition of exogenous methionine. The M. oryzae genome contains a second predicted MTHFR-encoding gene, MET12. The deduced amino acid sequences of Met13 and Met12 share 32% identity. Interestingly, Δmet12 mutants produced significantly less conidia compared with the isogenic wild-type strain and grew very poorly in the absence of methionine, but were fully pathogenic. Deletion of both genes resulted in Δmet13Δmet12 mutants that showed similar phenotypes to single Δmet13 mutants. Taken together, we conclude that the MTHFR gene, MET13, is essential for infection-related morphogenesis by the rice blast fungus M. oryzae. PMID:24116181

  7. Prevalence of MTHFR C677T Polymorphism in North Indian Mothers Having Babies with Trisomy 21 Down Syndrome

    ERIC Educational Resources Information Center

    Kohli, Utkarsh; Arora, Sadhna; Kabra, Madhulika; Ramakrishnan, Lakshmy; Gulati, Sheffali; Pandey, Ravindra

    2008-01-01

    Recent studies have evaluated possible links between polymorphisms in maternal folate metabolism genes and Down syndrome. Some of these studies show a significantly increased prevalence of the C677T polymorphism of the 5,10-methylene tetrahydrofolate reductase (NADPH) gene (MTHFR) among mothers who have had babies with Down syndrome. This study

  8. Association of Polymorphisms in BDNF, MTHFR, and Genes Involved in the Dopaminergic Pathway with Memory in a Healthy Chinese Population

    ERIC Educational Resources Information Center

    Yeh, Ting-Kuang; Hu, Chung-Yi; Yeh, Ting-Chi; Lin, Pei-Jung; Wu, Chung-Hsin; Lee, Po-Lei; Chang, Chun-Yen

    2012-01-01

    The contribution of genetic factors to the memory is widely acknowledged. Research suggests that these factors include genes involved in the dopaminergic pathway, as well as the genes for brain-derived neurotrophic factor (BDNF) and methylenetetrahydrofolate reductase (MTHFR). The activity of the products of these genes is affected by single…

  9. Prevalence of MTHFR C677T Polymorphism in North Indian Mothers Having Babies with Trisomy 21 Down Syndrome

    ERIC Educational Resources Information Center

    Kohli, Utkarsh; Arora, Sadhna; Kabra, Madhulika; Ramakrishnan, Lakshmy; Gulati, Sheffali; Pandey, Ravindra

    2008-01-01

    Recent studies have evaluated possible links between polymorphisms in maternal folate metabolism genes and Down syndrome. Some of these studies show a significantly increased prevalence of the C677T polymorphism of the 5,10-methylene tetrahydrofolate reductase (NADPH) gene (MTHFR) among mothers who have had babies with Down syndrome. This study…

  10. Variants in maternal COMT and MTHFR genes and risk of neural tube defects in offspring.

    PubMed

    Liu, Jufen; Zhang, Yali; Jin, Lei; Li, Guoxing; Wang, Linlin; Bao, Yanping; Fu, Yunting; Li, Zhiwen; Zhang, Le; Ye, Rongwei; Ren, Aiguo

    2015-04-01

    Methylenetetrahydrofolate reductase (MTHFR) C677T and catechol-O-Methyltransferase (COMT) G158A are associated with a risk of neural tube defects (NTDs) in offspring. This study examined the effect of a MTHFR × COMT interaction on the risk of NTDs in a Chinese population with a high prevalence of NTDs. A total of 576 fetuses or newborns with NTDs and 594 controls were genotyped for MTHFRrs1801133, MTHFRrs1801131, and COMTrs4680 and COMTrs737865. Information on maternal sociodemographic characteristics, reproductive history, and related behavior was collected through face-to-face interviews. Possible interactions between genetic variants of MTHFR and COMT were examined. MTHFR C677T homozygous TT was associated with an elevated risk of total NTDs (odds ratio [OR] = 1.37, 95 % confidence interval [CI] = 0.93-2.03) and of anencephaly (OR = 1.67, 95 % CI = 0.98-2.84) compared with the CC genotype. There was a COMT rs737865 CC × MTHFR rs1801133 TT interaction for total NTDs (OR = 3.02, 95 % CI = 1.00-9.14) and for anencephaly (OR = 3.39, 95 % CI = 0.94-12.18). No interaction was found between COMT rs4680 AA/AG and MTHFR CT/TT genotypes for total NTDs or any subtype of NTD. The interaction of COMT rs737865 and MTHFR C677T was associated with an increased risk of NTDs, especially anencephaly, in a Chinese population with a high prevalence of NTDs. PMID:24990354

  11. Frequency of APOE, MTHFR and ACE polymorphisms in the Zambian population

    PubMed Central

    2014-01-01

    Background Polymorphisms within the apolipoprotein-E (APOE), Methylenetetrahydrofolate reductase (MTHFR) and Angiotensin I-converting enzyme (ACE) genes has been associated with cardiovascular and cerebrovascular disorders, Alzheimer’s disease and other complex diseases in various populations. The aim of the study was to analyze the allelic and genotypic frequencies of APOE, MTHFR C677T and ACE I/D gene polymorphisms in the Zambian population. Results The allele frequencies of APOE polymorphism in the Zambian populations were 13.8%, 59.5% and 26.7% for the ε2, ε3 and ε4 alleles respectively. MTHFR C677T and ACE I/D allele frequencies were 8.6% and 13.8% for the T and D minor alleles respectively. The ε2ε2 genotype and TT genotype were absent in the Zambian population. The genetic distances between Zambian and other African and non-African major populations revealed an independent variability of these polymorphisms. Conclusion We found that the APOE ε3 allele and the I allele of the ACE were significantly high in our study population while there were low frequencies observed for the MTHFR 677 T and ACE D alleles. Our analysis of the APOE, MTHFR and ACE polymorphisms may provide valuable insight into the understanding of the disease risk in the Zambian population. PMID:24679048

  12. Association of the MTHFR rs1801131 and rs1801133 variants in sporadic Parkinson's disease patients.

    PubMed

    Yuan, Lamei; Song, Zhi; Deng, Xiong; Xiong, Wei; Yang, Zhijian; Deng, Hao

    2016-03-11

    Parkinson's disease (PD) is a common age-dependent neurodegenerative movement disorder related to multiple factors, and genetic factors play an important role in the pathogenesis of PD. Variants in the methylenetetrahydrofolate reductase gene (MTHFR), a gene encoding a folate-dependent enzyme that is involved in homocysteine metabolism, have been reported to be associated with PD. To explore the role of the MTHFR gene in the development of PD in Chinese Han population, we analyzed two MTHFR variants (rs1801131 and rs1801133) in a patient cohort consisting of 512 patients with PD from mainland China and a control cohort consisting of 512 age, gender and ethnicity matched normal subjects. Statistically significant differences in genotypic and allelic frequencies were detected in the MTHFR variant rs1801133 (P=0.022 and 0.007, respectively; odds ratio=0.780, 95% confidence interval=0.651-0.934). In addition, the A-T haplotype of rs1801131-rs1801133 showed a protective role against PD development (P=0.007, odds ratio=0.779, 95% confidence interval=0.650-0.933). Our results suggested that the T allele of rs1801133 variant and A-T haplotype of rs1801131-rs1801133 in the MTHFR gene may decrease the risk of developing PD in Chinese Han population from mainland China. PMID:26806866

  13. C677T (RS1801133 ) MTHFR gene polymorphism frequency in a colombian population

    PubMed Central

    Gómez-Gutierrez, Alberto; Gómez, Piedad Elena; Casas-Gomez, Maria Consuelo; Briceño, Ignacio

    2015-01-01

    Introduction: Abnormal levels of the enzyme methylenetetrahydrofolate reductase (MTHFR) are associated with an increased risk of both cardiovascular and cerebrovascular disease and higher concentrations of homocysteine. Abnormal levels are also related to birth defects, pregnancy complications, cancer and toxicity to methotrexate (MTX). Polymorphisms of MTHFR affect the activity of the enzyme. Genetic associations have been related to treatment efficacy. Objective: To establish the frequency of the C> T polymorphism at nucleotide 677 of the MTHFR gene in a group of Colombian individuals. Methods: Data from pharmacogenetic microarrays that include MTX sensibility-associated polymorphisms were retrospectively collected (Pathway Genomics®). The frequency of the C> T MTHFR rs1801133 marker polymorphism was analyzed. Results: Microarray data from 68 men and 84 women were analyzed. Comparisons of genotype C/C vs. C/T and T/T were statistically significantly different (p= 0.00, p= 0.026, respectively), as were C/T and T / T (p= 0.0001). Conclusions: Results for the C/C and C/T genotypes in a Colombian population are similar to other previously studied groups of healthy subjects. Subjects from our population might be at risk of developing diseases associated with MTHFR polymorphisms and might present toxicity and adverse effects if treated with MTX, which suggests the need to evaluate therapeutic alternatives based on individual pharmacogenetic studies. PMID:26309343

  14. No association between MTHFR A1298C and MTRR A66G polymorphisms, and MS in an Australian cohort.

    PubMed

    Szvetko, A L; Fowdar, J; Nelson, J; Colson, N; Tajouri, L; Csurhes, P A; Pender, M P; Griffiths, L R

    2007-01-15

    Multiple sclerosis (MS) is a complex neurological disease that affects the central nervous system (CNS) resulting in debilitating neuropathology. Pathogenesis is primarily defined by CNS inflammation and demyelination of nerve axons. Methionine synthase reductase (MTRR) is an enzyme that catalyzes the remethylation of homocysteine (Hcy) to methionine via cobalamin and folate dependant reactions. Cobalamin acts as an intermediate methyl carrier between methylenetetrahydrofolate reductase (MTHFR) and Hcy. MTRR plays a critical role in maintaining cobalamin in an active form and is consequently an important determinant of total plasma Hcy (pHcy) concentrations. Elevated intracellular pHcy levels have been suggested to play a role in CNS dysfunction, neurodegenerative, and cerebrovascular diseases. Our investigation entailed the genotyping of a cohort of 140 cases and matched controls for MTRR and MTHFR, by restriction length polymorphism (RFLP) techniques. Two polymorphisms: MTRR A66G and MTHFR A1298C were investigated in an Australian age and gender matched case-control study. No significant allelic frequency difference was observed between cases and controls at the alpha = 0.05 level (MTRR chi2 = 0.005, P = 0.95, MTHFR chi2 = 1.15, P = 0.28). Our preliminary findings suggest no association between the MTRR A66G and MTHFR A1298C polymorphisms and MS. PMID:17113603

  15. Lack of association between MTHFR C677T polymorphism and breast cancer risk in Ahvaz, west south-Iran

    PubMed Central

    Mohammadzadeh, Ghorban; Karimi, Maryam; Bazyar, Mohammad; Hosseini, Seyed-Mohammad

    2016-01-01

    Background: Association between C677T polymorphism of the methylenetetrahydrofolate reductase (MTHFR), a key enzyme involved in folate metabolism and DNA methylation, and breast cancer risk are inconsistent. We investigated in a case-control study, possible effect of the common MTHFR C677T polymorphism on breast cancer risk in a sample of Iranian patients. Materials and Methods: The study subjects comprised of 123 breast cancer cases and 110 cancer-free control, who were matched for age and body mass index (BMI). C677T genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Lipid profile was measured in all subjects by standard method. Results: The genotypes distributions (CC, CT, and TT) were 55.3, 39, and 5.7% in breast cancer cases and 51.8, 44.5, and 3.6% in controls. Chi square analysis revealed that there was no significant association between breast cancer risk and MTHFR genotypes and alleles. Additionally, no significant association was observed between C677T genotypes and biochemistry parameters. A multinomial logistic regression model with MTHFR genotypes, lipid profiles, BMI and age as covariates revealed that there is no significant association between MTHFR genotypes and risk of breast cancer, but higher values of LDL and HDL significantly increase risk of breast cancer. Conclusions: Our findings do not support the hypothesis that genetic variation in the MTHFR C677T polymorphism is implicated in the breast cancer risk in a sample of Iranian patients. PMID:27014653

  16. C677T and A1298C MTHFR polymorphisms, a challenge for antifolate and fluoropyrimidine-based therapy personalisation.

    PubMed

    De Mattia, Elena; Toffoli, Giuseppe

    2009-05-01

    Pharmacogenetics represents an exciting, new promising tool for the individualisation of therapy. Several genetic polymorphisms and haplotypes have been considered in an attempt to optimise therapy with specific drugs but, up to now, their clinical applications remain limited. 5,10-Methylenetetrahydrofolate reductase (MTHFR), a key enzyme of one-carbon metabolism, catalyses the irreversible conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate. Two common non-synonymous variants, the C677T (Ala222Val) and A1298C (Glu429Ala), were described for the MTHFR gene and associated with a decreased enzymatic activity and an alteration of intracellular folate distribution. Other MTHFR polymorphisms with marginal impact on enzymatic activity were also reported. Several published clinical studies have investigated the potential predictive role of C677T and A1298C genetic variants on toxicity and efficacy of antifolate and fluoropyrimidine agents, such as methotrexate (MTX), 5-fluorouracil (5-FU) and raltitrexed. Many of these studies show significant associations with MTHFR variants, but others report neither association nor opposite results. A significant interaction between MTHFR polymorphisms and nutrient/environmental factors (i.e. folate status) as well as the ethnicity was reported. Finally, a haplotype approach and the combined analysis of multiple folate pathway gene variants seem to provide a more comprehensive strategy compared to single-locus investigations. The aim of this review is to critically analyse the available data on the importance of MTHFR polymorphisms in modulating the clinical outcome of antifolate and fluoropyrimidine therapies. PMID:19144510

  17. Try235Phe homozygous mutation of the steroid 5-a reductase type 2 (SRD5A2) gene in a Turkish patient.

    PubMed

    Parlak, Mesut; Durmaz, Erdem; Gursoy, Semin; Bircan, Iffet; Akcurin, Sema

    2014-01-01

    Steroid 5-a reductase type 2 isoenzyme (SRD5A2) deficiency is a male-limited autosomal recessive disorder that results in decreased conversion of testosterone to dihydrotestosterone with various de.gree of incomplete virilization in affected 46, XY infants. No clear genotype-phenotype relationship has been reported till date; moreover, the same mutation can result in considerable heterogeneity in clinical manifestations. Of 6 documented cases with Try235Phe homozygous mutation of the SRD5A2 gene, 3 patients had predominantly female external genitalia whereas the other 3 had predominantly male phenotype. We report Try235Phe homozygous mutation of the SRD5A2 gene in a Turkish patient who was initially assigned as a girl because of the predominantly female appearance of the external genitalia. PMID:25266188

  18. Gender-Specific Effect of Mthfr Genotype and Neonatal Vigabatrin Interaction on Synaptic Proteins in Mouse Cortex

    PubMed Central

    Blumkin, Elinor; Levav-Rabkin, Tamar; Melamed, Osnat; Galron, Dalia; Golan, Hava M

    2011-01-01

    The enzyme methylenetetrahydrofolate reductase (MTHFR) is a part of the homocysteine and folate metabolic pathways, affecting the methylations of DNA, RNA, and proteins. Mthfr deficiency was reported as a risk factor for neurodevelopmental disorders such as autism spectrum disorder and schizophrenia. Neonatal disruption of the GABAergic system is also associated with behavioral outcomes. The interaction between the epigenetic influence of Mthfr deficiency and neonatal exposure to the GABA potentiating drug vigabatrin (GVG) in mice has been shown to have gender-dependent effects on mice anxiety and to have memory impairment effects in a gender-independent manner. Here we show that Mthfr deficiency interacts with neonatal GABA potentiation to alter social behavior in female, but not male, mice. This impairment was associated with a gender-dependent enhancement of proteins implicated in excitatory synapse plasticity in the female cortex. Reelin and fragile X mental retardation 1 protein (FMRP) levels and membrane GluR1/GluR2 ratios were elevated in wild-type mice treated neonatally with GVG and in Mthfr+/− mice treated with saline, but not in Mthfr+/− mice treated with GVG, compared with control groups (wild type treated with saline). A minor influence on the levels of these proteins was observed in male mice cortices, possibly due to high basal protein levels. Interaction between gender, genotype, and treatment was also observed in the GABA pathway. In female mice, GABA Aα2/gephyrin ratios were suppressed in all test groups; in male mice, a genotype-specific enhancement of GABA Aα2/gephyrin was observed. The lack of an effect on either reln or Fmr1 transcription suggests post-transcriptional regulation of these genes. Taken together, these findings suggest that Mthfr deficiency may interact with neonatal GABA potentiation in a gender-dependent manner to interrupt synaptic function. This may illustrate a possible mechanism for the epigenetic involvement of Mthfr deficiency in neurodevelopmental disorders. PMID:21490592

  19. Significant impact of MTHFR C677T polymorphism on plasma homovanillic acid (HVA) levels among alcohol-dependent patients.

    PubMed

    Lutz, Ulrich C; Batra, Anil; Wiatr, Gerlinde; Machicao, Fausto; Kolb, Werner; Maurer, Sandra; Buchkremer, Gerhard; Khnke, Michael D

    2007-03-01

    The enzyme 5,10-methylenetetrahydrofolate reductase (MTHFR) synthesizes 5-methyltetrahydrofolate. It plays a critical role in homocysteine metabolism. A high impact of MTHFR C677T polymorphism on plasma homocysteine levels has been observed among alcoholics. Recent studies indicate that homocysteine has toxic effects on dopaminergic neurons. Thus it lowers levels of homovanillic acid (HVA) in the striatal region in rats. Alcoholics had significantly lower plasma HVA concentrations compared with healthy controls. Aim of this study is to elucidate whether HVA plasma levels in alcoholics are influenced by MTHFR C677T polymorphism. A total of 142 alcohol-dependent patients and 101 healthy controls were examined regarding plasma HVA concentration and MTHFR C677T genotype. Blood samples of alcoholics were obtained after a minimum of 22 days of abstinence. Among alcohol-dependent patients MTHFR C677T polymorphism was significantly associated with plasma HVA levels: carriers of MTHFR C677T T-allele had significantly lower HVA plasma levels compared with homozygote carriers of C-allele: 11.9 ng/ml versus 14.4 ng/ml (chi2: 5.39; P = 0.02). In healthy control subjects plasma HVA levels did not differ significantly between MTHFR C677T T-allele carriers and homozygote carriers of C-allele: 15.1 ng/ml versus 15.3 ng/ml (chi2: 0.04; P = 0.82). The data suggest an influence of MTHFR C677T polymorphism on plasma HVA among alcohol-dependent patients. This might be due to neurotoxic effects of homocysteine on the dopaminergic system or direct impairment of monoamine metabolism. Future studies should try to elucidate whether this effect is reversible during alcohol abstinence. PMID:17407503

  20. Gender-specific effect of Mthfr genotype and neonatal vigabatrin interaction on synaptic proteins in mouse cortex.

    PubMed

    Blumkin, Elinor; Levav-Rabkin, Tamar; Melamed, Osnat; Galron, Dalia; Golan, Hava M

    2011-07-01

    The enzyme methylenetetrahydrofolate reductase (MTHFR) is a part of the homocysteine and folate metabolic pathways, affecting the methylations of DNA, RNA, and proteins. Mthfr deficiency was reported as a risk factor for neurodevelopmental disorders such as autism spectrum disorder and schizophrenia. Neonatal disruption of the GABAergic system is also associated with behavioral outcomes. The interaction between the epigenetic influence of Mthfr deficiency and neonatal exposure to the GABA potentiating drug vigabatrin (GVG) in mice has been shown to have gender-dependent effects on mice anxiety and to have memory impairment effects in a gender-independent manner. Here we show that Mthfr deficiency interacts with neonatal GABA potentiation to alter social behavior in female, but not male, mice. This impairment was associated with a gender-dependent enhancement of proteins implicated in excitatory synapse plasticity in the female cortex. Reelin and fragile X mental retardation 1 protein (FMRP) levels and membrane GluR1/GluR2 ratios were elevated in wild-type mice treated neonatally with GVG and in Mthfr+/- mice treated with saline, but not in Mthfr+/- mice treated with GVG, compared with control groups (wild type treated with saline). A minor influence on the levels of these proteins was observed in male mice cortices, possibly due to high basal protein levels. Interaction between gender, genotype, and treatment was also observed in the GABA pathway. In female mice, GABA Aα2/gephyrin ratios were suppressed in all test groups; in male mice, a genotype-specific enhancement of GABA Aα2/gephyrin was observed. The lack of an effect on either reln or Fmr1 transcription suggests post-transcriptional regulation of these genes. Taken together, these findings suggest that Mthfr deficiency may interact with neonatal GABA potentiation in a gender-dependent manner to interrupt synaptic function. This may illustrate a possible mechanism for the epigenetic involvement of Mthfr deficiency in neurodevelopmental disorders. PMID:21490592

  1. Lack of an association between the ASN-108 mutation in the dihydrofolate reductase gene and in vivo resistance to sulfadoxine/pyrimethamine in Plasmodium falciparum.

    PubMed

    Rallón, N I; Osorio, L E; Giraldo, L E

    1999-08-01

    Sulfadoxine/pyrimethamine (SP) is considered an alternative treatment for acute uncomplicated malaria caused by Plasmodium falciparum resistant to chloroquine. However, the appearance of resistance to this drug has been reported since its initial use in Colombia. Molecular analysis of the dihydrofolate reductase gene indicates a correlation between in vitro resistance to SP and the Asn-108 point mutation. Little is known about the association of this point mutation and in vivo resistance to SP. We used a mutation-specific polymerase chain reaction strategy to analyze the presence of the Asn-108 point mutation in 48 clinical samples with adequate clinical response (ACR), 2 early treatment failures (ETF), and 1 late treatment failure (LTF). The Asn-108 mutation was detected in 36 of the ACR samples and in all of the ETF and LTF samples. Eleven ACR samples amplified with the wild-type-specific primer and one amplified with the primer for the Thr-108 mutation described for resistance to cycloguanil. These results suggest that the Asn-108 marker may not be useful in predicting SP treatment failure. PMID:10463674

  2. Tagging SNPs in the MTHFR Gene and Risk of Ischemic Stroke in a Chinese Population

    PubMed Central

    Zhou, Bao-Sheng; Bu, Guo-Yun; Li, Mu; Chang, Bin-Ge; Zhou, Yi-Pin

    2014-01-01

    Stroke is currently the leading cause of functional impairments worldwide. Folate supplementation is inversely associated with risk of ischemic stroke. Methylenetetrahydrofolate reductase (MTHFR) is an important enzyme involved in folate metabolism. The aim of this study is to examine whether genetic variants in MTHFR gene are associated with the risk of ischemic stroke and fasting total serum homocysteine (tHcy) level. We genotyped nine tag SNPs in the MTHFR gene in a case-control study, including 543 ischemic stroke cases and 655 healthy controls in China. We found that subjects with the rs1801133 TT genotype and rs1801131 CC genotype had significant increased risks of ischemic stroke (adjusted odds ratio (OR) = 1.82, 95% confidence interval (CI): 1.27–2.61, p = 0.004; adjusted OR = 1.99, 95% CI: 1.12–3.56, p = 0.01) compared with subjects with the major alleles. Haplotype analysis also found that carriers of the MTHFR CTTCGA haplotype (rs12121543-rs13306553-rs9651118-rs1801133-rs2274976-rs1801131) had a significant reduced risk of ischemic stroke (adjusted OR = 0.53, 95% CI: 0.35–0.82) compared with those with the CTTTGA haplotype. Besides, the MTHFR rs1801133 and rs9651118 were significantly associated with serum levels of tHcy in healthy controls (p < 0.0001 and p = 0.02). These findings suggest that variants in the MTHFR gene may influence the risk of ischemic stroke and serum tHcy. PMID:24853127

  3. MTHFR polymorphisms and Opisthorchis viverrini infection: a relationship with increased susceptibility to cholangiocarcinoma in Thailand.

    PubMed

    Songserm, Nopparat; Promthet, Supannee; Sithithaworn, Paiboon; Pientong, Chamsai; Ekalaksananan, Tipaya; Chopjitt, Peechanika; Parkin, Donald Maxwell

    2011-01-01

    Opisthorchis viverrini (OV) infection is the major risk factor for cholangiocarcinoma (CCA). Methylenetetrahydrofolate reductase (MTHFR) is an important enzyme in folate metabolism. Change in MTHFR activity may influence both DNA methylation and synthesis, crucial steps in carcinogenesis. This study aimed to investigate the association between MTHFR polymorphisms and OV infection with CCA risk in a high-incidence area of Thailand. A nested case-control study within cohort study was carried out: 219 subjects with primary CCA were matched with two non-cancer controls from the same cohort on sex, age at recruitment and presence/ absence of OV eggs in stool. At the time of recruitment information on consumption of foodstuffs potentially contaminated by OV was obtained by questionnaire. MTHFR polymorphisms were analyzed using PCR with high resolution melting analysis. Associations between variables and the risk of CCA were assessed using conditional logistic regression. Risk of CCA was related to consumption of a dish of raw freshwater fish (Koi- Pla) with clear dose-response effects, and there were joint effects on CCA risk between MTHFR polymorphisms and consumption of dishes containing raw- and/or semi-raw freshwater fish. This study provides evidence to support a relationship of increased susceptibility to CCA in individuals with MTHFR variants, especially for those individuals who have OV infection or consume semi-raw freshwater fish (acting either as a source of OV or of pre-formed nitrosamine). Folate may play an important role in OV-related cholangiocarcinogenesis by upsetting the balance between DNA methylation and synthesis in the folate pathway. PMID:21875294

  4. High folic acid consumption leads to pseudo-MTHFR deficiency, altered lipid metabolism, and liver injury in mice12345

    PubMed Central

    Christensen, Karen E; Mikael, Leonie G; Leung, Kit-Yi; Lévesque, Nancy; Deng, Liyuan; Wu, Qing; Malysheva, Olga V; Best, Ana; Caudill, Marie A; Greene, Nicholas DE

    2015-01-01

    Background: Increased consumption of folic acid is prevalent, leading to concerns about negative consequences. The effects of folic acid on the liver, the primary organ for folate metabolism, are largely unknown. Methylenetetrahydrofolate reductase (MTHFR) provides methyl donors for S-adenosylmethionine (SAM) synthesis and methylation reactions. Objective: Our goal was to investigate the impact of high folic acid intake on liver disease and methyl metabolism. Design: Folic acid–supplemented diet (FASD, 10-fold higher than recommended) and control diet were fed to male Mthfr+/+ and Mthfr+/− mice for 6 mo to assess gene-nutrient interactions. Liver pathology, folate and choline metabolites, and gene expression in folate and lipid pathways were examined. Results: Liver and spleen weights were higher and hematologic profiles were altered in FASD-fed mice. Liver histology revealed unusually large, degenerating cells in FASD Mthfr+/− mice, consistent with nonalcoholic fatty liver disease. High folic acid inhibited MTHFR activity in vitro, and MTHFR protein was reduced in FASD-fed mice. 5-Methyltetrahydrofolate, SAM, and SAM/S-adenosylhomocysteine ratios were lower in FASD and Mthfr+/− livers. Choline metabolites, including phosphatidylcholine, were reduced due to genotype and/or diet in an attempt to restore methylation capacity through choline/betaine-dependent SAM synthesis. Expression changes in genes of one-carbon and lipid metabolism were particularly significant in FASD Mthfr+/− mice. The latter changes, which included higher nuclear sterol regulatory element-binding protein 1, higher Srepb2 messenger RNA (mRNA), lower farnesoid X receptor (Nr1h4) mRNA, and lower Cyp7a1 mRNA, would lead to greater lipogenesis and reduced cholesterol catabolism into bile. Conclusions: We suggest that high folic acid consumption reduces MTHFR protein and activity levels, creating a pseudo-MTHFR deficiency. This deficiency results in hepatocyte degeneration, suggesting a 2-hit mechanism whereby mutant hepatocytes cannot accommodate the lipid disturbances and altered membrane integrity arising from changes in phospholipid/lipid metabolism. These preliminary findings may have clinical implications for individuals consuming high-dose folic acid supplements, particularly those who are MTHFR deficient. PMID:25733650

  5. MTHFR genetic polymorphism increases the risk of preterm delivery

    PubMed Central

    Nan, Yanrong; Li, Hongmei

    2015-01-01

    Aims: This study aimed to investigate the association between the methylene tetrahydrofolate reductase (MTHFR) gene C677T and A1298C polymorphisms and premature delivery susceptibility. Methods: With matched age and gender, 108 premature delivery pregnant women as cases and 108 healthy pregnant women as controls were recruited in this case-control study. The cases and controls had same gestational weeks. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was adopted to analyze C677T and A1298C polymorphisms of the participants. Linkage disequilibrium (LD) and haplotype analysis were conducted by Haploview software. The differences for frequencies of gene type, allele and haplotypes in cases and controls were tested by chi-square test. The relevant risk of premature delivery was represented by odds ratios (ORs) with 95% confidence intervals (95% CIs). Results: TT gene type frequency of C677T polymorphsim was higher in cases than the controls (P=0.004, OR=3.077, 95% CI=1.469-6.447), so was allele T (P=0.002, OR=1.853, 95% CI=1.265-2.716). Whereas, CC gene type of A1298C polymorphism had a lower distribution in cases than the controls (P=0.008, OR=0.095, 95% CI=0.012-0.775), so was allele C (P=0.047, OR=0.610, 95% CI=0.384-0.970). Haplotype analysis and linkage disequilibrium test conducted on the alleles of two polymorphisms in MTHFR gene, we discovered that haplotype T-A had a higher distribution in cases, which indicated that susceptible haplotype T-A was the candidate factor for premature delivery. Conclusions: Gene type TT of MTHFR C677T polymorphism might make premature delivery risk rise while gene type CC of A1298C polymorphism might have protective influence on premature delivery. PMID:26261642

  6. The Association of the MTHFR c.1625A>C Genetic Variant with the Risk of Congenital Heart Diseases in the Chinese

    PubMed Central

    Wang, Yuting; Sun, Lei; Du, Weina; Song, Shuang; Wang, Shuo; Jiang, Weiju; Huang, Tianchu

    2015-01-01

    The purpose of this study is to investigate the association of methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms with the risk of congenital heart diseases (CHD). The genotypes of the MTHFR genetic variant were determined by the polymerase chain reactionrestriction fragment length polymorphism and DNA sequencing methods. Our data suggested that the allelic and genotypic frequencies of CHD patients were significantly different from non-CHD controls. The MTHFR c.1625A>C genetic variant was significantly associated with the increased risk of CHD (CC vs. AA: odds ratio [OR]=2.29, 95% confidence interval [CI] 1.154.53, p=0.016; C vs. A: OR=1.47, 95% CI 1.111.96, p=0.008). Results from this study indicate that the MTHFR c.1625A>C genetic variant influences the risk of CHD in the studied population. PMID:25494855

  7. Association between the MTHFR C677T gene polymorphism and essential hypertension in South West Cameroon.

    PubMed

    Ghogomu, S M; Ngolle, N E; Mouliom, R N; Asa, B F

    2016-01-01

    The association of the methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism and essential hypertension has been reported but with controversial results in diverse populations in Asia and Europe, thereby suggesting a dependency on ethnicity. The aim of this study was to investigate the association between the MTHFR C677T polymorphism and essential hypertension in a Cameroonian population (Bantu ethnic group) of the South West Region. Analysis of anthropometric and biochemical data in hypertensive and normotensive subjects revealed that age, systolic blood pressure, diastolic blood pressure, low-density lipoprotein cholesterol, serum total cholesterol, and triglycerides are independent risk factors for essential hypertension. Substitution of thymine for cytosine at position 667 of the MTHFR gene was determined by polymerase chain reaction-restriction fragment length polymorphism. Genotype frequencies were found to be 7.3% CC, 58.5% CT, and 34.1% TT for hypertensive subjects compared to 90.0% CC, 10.0% CT, and 0.0% TT for normotensives. Allele frequencies were obtained as 36.6% C and 63.4% T for hypertensive subjects and 95.0% C and 5.0% T for normotensive subjects. These results reveal that the T allele predisposes individuals to hypertension. Therefore, there is an association between variants of the MTHFR gene and hypertension in Cameroonian patients from the South West region. PMID:27051013

  8. Polymorphisms in MTHFR, MS and CBS Genes and Homocysteine Levels in a Pakistani Population

    PubMed Central

    Yakub, Mohsin; Moti, Naushad; Parveen, Siddiqa; Chaudhry, Bushra; Azam, Iqbal; Iqbal, Mohammad Perwaiz

    2012-01-01

    Background Hyperhomocysteinemia (>15 mol/L) is highly prevalent in South Asian populations including Pakistan. In order to investigate the genetic determinants of this condition, we studied 6 polymorphisms in genes of 3 enzymes - methylenetetrahydrofolate reductase (MTHFR; C677T; A1298C), methionine synthase (MS; A2756G), cystathionine-?-synthase (CBS; T833C/844ins68, G919A) involved in homocysteine metabolism and investigated their interactions with nutritional and environmental factors in a Pakistani population. Methodology/Principal Findings In a cross-sectional survey, 872 healthy adults (355 males and 517 females; age 1860 years) were recruited from a low-income urban population in Karachi. Fasting venous blood was obtained and assessed for plasma/serum homocysteine; folate, vitamin B12, pyridoxal phosphate and blood lead. DNA was isolated and genotyping was performed by PCR-RFLP (restriction-fragment-length- polymorphism) based assays. The average changes in homocysteine levels for MTHFR 677CT and TT genotypes were positive [?(SE ?), 2.01(0.63) and 16.19(1.8) mol/L, respectively]. Contrary to MTHFR C677T polymorphism, the average changes in plasma homocysteine levels for MS 2756AG and GG variants were negative [?(SE ?), ?0.56(0.58) and ?0.83(0.99) mol/L, respectively]. The average change occurring for CBS 844ins68 heterozygous genotype (ancestral/insertion) was ?1.88(0.81) mol/L. The combined effect of MTHFR C677T, MS A2756G and CBS 844ins68 genotypes for plasma homocysteine levels was additive (p value <0.001). Odds of having hyperhomocysteinemia with MTHFR 677TT genotype was 10-fold compared to MTHFR 677CC genotype [OR (95%CI); 10.17(3.628.67)]. Protective effect towards hyperhomocysteinemia was observed with heterozygous (ancestral/insertion) genotype of CBS 844ins68 compared to homozygous ancestral type [OR (95% CI); 0.58 (0.340.99)]. Individuals with MTHFR 677CT or TT genotypes were at a greater risk of hyperhomocysteinemia in folate and vitamin B12 deficiencies and high blood lead (p value <0.05) level. Conclusions Gene polymorphism (especially MTHFR C677T transition), folate and vitamin B12 deficiencies, male gender and high blood lead level appear to be contributing towards the development of hyperhomocysteinemia in a Pakistani population. PMID:22470444

  9. Polymorphisms in the methylene tetrahydrofolate reductase and methionine synthase reductase genes and their correlation with unexplained recurrent spontaneous abortion susceptibility.

    PubMed

    Zhu, L

    2015-01-01

    We aimed to explore the correlation between unexplained recurrent spontaneous abortion and polymorphisms in the methylene tetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) genes. A case control study was conducted in 118 patients with unexplained recurrent spontaneous abortion (abortion group) and 174 healthy women (control group). The genetic material was extracted from the oral mucosal epithelial cells obtained from all subjects. The samples were subjected to fluorescence quantitative PCR to detect the single nucleotide polymorphisms (SNPs) in the MTHFR (C677T and A1298C) and MTRR (A66G) gene loci. The distribution frequency (18/118, 15.3%) of the MTHFR 677TT genotype was significantly higher in the abortion group (χ2 = 11.006, P = 0.004) than in the control group (2/174, 1.1%); on the other hand, the distribution frequency of the MTHFR A1298C genotype did not significantly differ between the abortion and control groups (χ(2) = 0.441, P = 0.507). The distribution frequency of the MTRR A66G genotype was also significantly higher in the abortion group (14/118, 11.9%; χ(2) = 10.503, P = 0.005) than in the control group (8/174, 4.6%). The MTHFR C677T and MTRR A66G polymorphisms are significantly correlated with the occurrence of spontaneous abortion. PMID:26345779

  10. Prevalence of MTHFR C677T and MS A2756G polymorphisms in major depressive disorder, and their impact on response to fluoxetine treatment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To examine the prevalence of the C677T polymorphism of the methylene tetrahydrofolate reductase (MTHFR) gene and the A2756G polymorphism of methionine synthase (MS), and their impact on antidepressant response. We screened 224 subjects (52% female, mean age 39 +/- 11 years) with SCID-diagnosed major...

  11. Infants' MTHFR polymorphisms and nonsyndromic orofacial clefts susceptibility: a meta-analysis based on 17 case-control studies.

    PubMed

    Pan, Yongchu; Zhang, Weibing; Ma, Junqing; Du, Yifei; Li, Dandan; Cai, Qi; Jiang, Hongbing; Wang, Meilin; Zhang, Zhengdong; Wang, Lin

    2012-09-01

    Methylenetetrahydrofolate reductase (MTHFR), an important enzyme in folate metabolism, is thought to be involved in the development of nonsyndromic orofacial clefts (NSOC). However, conflicting results have been achieved when evaluating the associations between infants' MTHFR C677T and A1298C polymorphisms and the risk of NSOC. To obtain more precise estimations of these associations, a meta-analysis recruiting 17 case-control studies was performed. Among Asians we found that CT heterozygote, TT homozygote, and CT/TT of infants' MTHFR C677T variant could contribute to elevated risks of NSOC, compared with CC wild-type homozygote (OR=1.741, 95% CI=1.043-2.907 for CT vs. CC, OR=2.311, 95% CI=1.313-4.041 for TT vs. CC, and OR=1.740, 95% CI=1.051-2.882 for CT/TT vs. CC, respectively). Similar effect was also observed on MTHFR 677T T allele, when using C allele as a reference in Asians (OR=1.420, 95% CI=1.191-1.693, for T allele vs. C allele). Furthermore, in stratified analysis by types of disease, CT/CC was suggested to confer decreased susceptibility to CL/P under recessive genetic model (OR=0.854, 95% CI=0.730-1.000). For MTHFR A1298C, the MTHFR 1298C allele in the case group of Caucasians was significantly lower than that in the control group, suggesting a protective effect against NSOC in Caucasian populations (OR=0.711, 95% CI=0.641-0.790, for C allele vs. A allele). In conclusion, the meta-analysis provided confirmative evidences that infants' MTHFR C677T and A1298C polymorphisms were involved in the development of NSOC. PMID:22847888

  12. Enrichment of MTHFR 677 T in a Chinese long-lived cohort and its association with lipid modulation

    PubMed Central

    2014-01-01

    Background Variants in the Methylenetetrahydrofolate reductase (MTHFR) gene may result in a lowered catalytic activity and associate with subsequent elevated serum homocysteine (Hcy) concentration, abnormal DNA synthesis and methylation, cardiovascular risk, and unhealthy aging. Several investigations on the relationship of MTHFR C677T polymorphism with serum lipid profile and longevity have been conducted in some populations, but the findings remain mixed. Herein, we sought to look at the association between MTHFR C677T and lipid profile in a longevous cohort in Bama, a well-known home of longevity in China. Methods Genotyping of MTHFR C677T was undertaken in 516 long-lived inhabitants (aged 90 and older, long-lived group, LG) and 493 healthy controls (aged 60–75, non-long-lived group, non-LG) recruited from Bama area. Correlation between MTHFR genotypes and lipids was then evaluated. Results T allele and TT genotype were significantly more prevalent in LG (P = 0.001 and 0.002, respectively), especially in females, than in non-LG. No difference in the tested lipid measures among MTHFR C677T genotypes was observed in LG, non-LG and total population (P > 0.05 for all). However, female but not male T carriers exhibited higher TC and LDL-C levels than did T noncarriers in the total population and in LG after stratification by sex (P < 0.05 for each). These differences did not however remain through further subdivision by hyperlipidemia and normolipidemia. Conclusion The higher prevalence of MTHFR 677 T genotypes and its modest unfavorable impact on lipids in Bama long-lived individuals may imply an existence of other protective genotypes which require further determination. PMID:24968810

  13. Status of vitamin B-12 and B-6 but not of folate, homocysteine and the methylenetetrahydrofolate reductase C677T polymorphism are associated with impaired cognition and depression in adults

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The C677T polymorphism of the methylene tetrahydrofolate reductase (MTHFR) gene differs in frequency in different ethnic groups which have differing prevalence of age-related cognitive impairments. We used a battery of neuropsychological tests to examine association of the MTHFR C677T polymorphism w...

  14. A potential interaction between COMT and MTHFR genetic variants in Han Chinese patients with bipolar II disorder

    PubMed Central

    Wang, Liang-Jen; Lee, Sheng-Yu; Chen, Shiou-Lan; Chang, Yun-Hsuan; Chen, Po See; Huang, San-Yuan; Tzeng, Nian-Sheng; Chen, Kao Chin; Lee, I. Hui; Wang, Tzu-Yun; Yang, Yen Kuang; Lu, Ru-Band

    2015-01-01

    Bipolar II disorder (BP-II), characterized by recurrent dysregulation of mood, is a serious and chronic psychiatric illness. However, BP-II is commonly under-recognized, even in psychiatric settings. Because dopaminergic disturbance is thought to be involved in the development of bipolar disorder (BPD), it seems essential to investigate dopamine-related genes like the catechol-O-methyltransferase (COMT) gene, which are involved in dopamine metabolism, and the methylenetetrahydrofolate reductase (MTHFR) gene, which may affect COMT methylation and COMT function. The current study examined the association and interaction of the COMT Val158Met and MTHFR C677T variants with BP-II. Nine hundred seventy-eight participants were recruited: 531 with BP-II and 447 healthy controls. The genotypes of the COMT and MTHFR polymorphisms were determined using a polymerase chain reaction-restriction fragment length polymorphism analysis. Logistic regression analysis showed a significant interaction effect of the COMT Val158Met Val/Val genotype and the MTHFR C677T C/T + T/T genotype (P = 0.039) for the protective effect on the odds of developing BP-II. Our findings support preliminary evidence that the COMT and MTHFR genes interact in BP-II, and they imply the connection of both dopaminergic pathways and methylation pathways in the pathogenesis of BP-II. PMID:25744938

  15. A Study on MTHFR C677T Gene Polymorphism and Alcohol Dependence among Meiteis of Manipur, India

    PubMed Central

    Singh, Huidrom Suraj; Salam, Kabita; Saraswathy, Kallur Nava

    2014-01-01

    Chronic alcohol consumption is reported to be associated with increase in plasma homocysteine levels which is further influenced by the polymorphism in methylenetetrahydrofolate reductase (MTHFR) gene. The present study aims to understand the extent of the MTHFR C677T polymorphism in alcohol dependent (AD) cases of Meiteis of Manipur, a Mendelian population of India. MTHFR C677T polymorphism was screened in 313 controls and 139 alcohol dependent (AD) cases who all met DSM-IV criteria for alcohol dependence. Both AD cases and controls were unrelated up to 1st cousin. Among the control group, different drinking patterns like abstainer/nondrinkers (NDs), occasional drinkers (ODs), and moderate drinkers (MDs) are included. Both the groups were found to be in Hardy-Weinberg equilibrium (P > 0.05). Genotypic and allelic frequency distribution of MTHFR C677T polymorphism did not differ significantly between AD cases and controls (P > 0.05). However, individuals carrying mutant (T) allele show more than 1-fold increased risk for AD though not significant (OR?=?1.43; 95% CI 0.415.01, P > 0.05). In conclusion, MTHFR C677T polymorphism is not found to be risk marker for AD in present studied population. However, higher prevalence of the mutant T allele may exacerbate deleterious health risk in future especially among alcohol drinkers. PMID:26317030

  16. Defining the role of mutations in Plasmodium vivax dihydrofolate reductase-thymidylate synthase gene using an episomal Plasmodium falciparum transfection system.

    PubMed

    Auliff, Alyson M; Adams, John H; O'Neil, Michael T; Cheng, Qin

    2010-09-01

    Plasmodium vivax resistance to antifolates is prevalent throughout Australasia and is caused by point mutations within the parasite dihydrofolate reductase (DHFR)-thymidylate synthase. Several unique mutations have been reported in P. vivax DHFR, and their roles in resistance to classic and novel antifolates are not entirely clear due, in part, to the inability to culture P. vivax in vitro. In this study, we use a homologous system to episomally express both wild-type and various mutant P. vivax dhfr (pvdhfr) alleles in an antifolate-sensitive line of P. falciparum and to assess their influences on the susceptibility of the recipient P. falciparum line to commonly used and new antifolate drugs. Although the wild-type pvdhfr-transfected P. falciparum line was as susceptible to antifolate drugs as the P. falciparum parent line, the single (117N), double (57L/117T and 58R/117T), and quadruple (57L/58R/61M/117T) mutant pvdhfr alleles conferred a marked reduction in their susceptibilities to antifolates. The resistance index increased with the number of mutations in these alleles, indicating that these mutations contribute to antifolate resistance directly. In contrast, the triple mutant allele (58R/61M/117T) significantly reversed the resistance to all antifolates, indicating that 61M may be a compensatory mutation. These findings help elucidate the mechanism of antifolate resistance and the effect of existing mutations in the parasite population on the current and new generation of antifolate drugs. It also demonstrates that the episomal transfection system has the potential to provide a rapid screening system for drug development and for studying drug resistance mechanisms in P. vivax. PMID:20566761

  17. Defining the Role of Mutations in Plasmodium vivax Dihydrofolate Reductase-Thymidylate Synthase Gene Using an Episomal Plasmodium falciparum Transfection System?

    PubMed Central

    Auliff, Alyson M.; Adams, John H.; O'Neil, Michael T.; Cheng, Qin

    2010-01-01

    Plasmodium vivax resistance to antifolates is prevalent throughout Australasia and is caused by point mutations within the parasite dihydrofolate reductase (DHFR)-thymidylate synthase. Several unique mutations have been reported in P. vivax DHFR, and their roles in resistance to classic and novel antifolates are not entirely clear due, in part, to the inability to culture P. vivax in vitro. In this study, we use a homologous system to episomally express both wild-type and various mutant P. vivax dhfr (pvdhfr) alleles in an antifolate-sensitive line of P. falciparum and to assess their influences on the susceptibility of the recipient P. falciparum line to commonly used and new antifolate drugs. Although the wild-type pvdhfr-transfected P. falciparum line was as susceptible to antifolate drugs as the P. falciparum parent line, the single (117N), double (57L/117T and 58R/117T), and quadruple (57L/58R/61M/117T) mutant pvdhfr alleles conferred a marked reduction in their susceptibilities to antifolates. The resistance index increased with the number of mutations in these alleles, indicating that these mutations contribute to antifolate resistance directly. In contrast, the triple mutant allele (58R/61M/117T) significantly reversed the resistance to all antifolates, indicating that 61M may be a compensatory mutation. These findings help elucidate the mechanism of antifolate resistance and the effect of existing mutations in the parasite population on the current and new generation of antifolate drugs. It also demonstrates that the episomal transfection system has the potential to provide a rapid screening system for drug development and for studying drug resistance mechanisms in P. vivax. PMID:20566761

  18. Thermolabile methylenetetrahydrofolate reductase: an inherited risk factor for coronary artery disease.

    PubMed Central

    Kang, S S; Wong, P W; Susmano, A; Sora, J; Norusis, M; Ruggie, N

    1991-01-01

    Severe methylenetetrahydrofolate reductase (MTHFR) deficiency with less than 2% of normal enzyme activity is characterized by neurological abnormalities, atherosclerotic changes, and thromboembolism. We have discovered a "new" variant of MTHFR deficiency which is characterized by the absence of neurological abnormalities, an enzyme activity of about 50% of the normal value, and distinctive thermolability under specific conditions of heat inactivation. In this study, lymphocyte MTHFR specific activities in the thermolabile variant and control groups were 5.58 +/- 0.91 and 10.33 +/- 2.89 nmol formaldehyde formed/mg protein/h, respectively. The difference was significant (P less than .01). However, there was overlap among the individual values from the two groups. On the other hand, residual MTHFR activity after heat inactivation was 11.2 +/- 1.43% in the thermolabile variant and 36.3 +/- 5.18% in the controls. There was no overlap. Enzyme studies in 10 subjects with thermolabile MTHFR and their family members support the hypothesis that thermolabile MTHFR is inherited as an autosomal recessive trait. To elucidate the association of thermolabile MTHFR with the development of coronary artery disease, we determined the thermostability of lymphocyte MTHFR in 212 patients with proven coronary artery disease and in 202 controls without clinical evidence of atherosclerotic vascular disease. Thermolabile MTHFR was found in 36 (17.0%) cardiac patients and 10 (5.0%) controls. The difference in incidence between the two groups was statistically significant (P less than .01). The average age at onset of clinical coronary artery disease in 36 patients with thermolabile MTHFR was 57.3 +/- 7.6 years (35-72 years). The mean total plasma homocysteine concentration in patients with thermolabile MTHFR was 13.19 +/- 5.32 nmol/ml and was significantly different from the normal mean of 8.50 +/- 2.80 nmol/ml (P less than .05). There was no association between thermolabile MTHFR and other major risk factors. We conclude that thermolabile MTHFR is a variant(s) of MTHFR deficiency which is inherited as an autosomal recessive trait. In addition, it is positively associated with the development of coronary artery disease. Determination of in vitro thermostability of lymphocyte MTHFR is a reliable method for identifying subjects with this abnormality. PMID:1998339

  19. Association between MTHFR gene polymorphisms and the risk of autism spectrum disorders: a meta-analysis.

    PubMed

    Pu, Danhua; Shen, Yiping; Wu, Jie

    2013-10-01

    Methylenetetrahydrofolate reductase (MTHFR) is essential for DNA biosynthesis and the epigenetic process of DNA methylation, and its gene polymorphisms have been implicated as risk factors for birth defects, neurological disorders, and cancers. However, reports on the association of MTHFR polymorphisms with autism spectrum disorders (ASD) are inconclusive. Therefore, we investigated the relationship of the MTHFR polymorphisms (C677T and A1298C) and the risk of ASD by meta-analysis. Up to December 2012, eight case-control studies involving 1672 patients with ASD and 6760 controls were included for meta-analysis. The results showed that the C677T polymorphism was associated with significantly increased ASD risk in all the comparison models [T vs. C allele (frequency of allele): odds ratio (OR) = 1.42, 95% confidence interval (CI): 1.09-1.85; CT vs. CC (heterozygote): OR = 1.48, 95% CI: 1.09-2.00; TT vs. CC (homozygote): OR = 1.86, 95% CI: 1.08-3.20; CT+TT vs. CC (dominant model): OR = 1.56, 95% CI: 1.12-2.18; and TT vs. CC+CT (recessive model): OR = 1.51, 95% CI: 1.02-2.22], whereas the A1298C polymorphism was found to be significantly associated with reduced ASD risk but only in a recessive model (CC vs. AA+AC: OR = 0.73, 95% CI: 0.56-0.97). In addition, we stratified the patient population based on whether they were from a country with food fortification of folic acid or not. The meta-analysis showed that the C677T polymorphism was found to be associated with ASD only in children from countries without food fortification. Our study indicated that the MTHFR C677T polymorphism contributes to increased ASD risk, and periconceptional folic acid may reduce ASD risk in those with MTHFR 677C>T polymorphism. PMID:23653228

  20. Meta-analysis of associations between MTHFR and GST polymorphisms and susceptibility to multiple sclerosis.

    PubMed

    Lee, Young Ho; Seo, Young Ho; Kim, Jae-Hoon; Choi, Sung Jae; Ji, Jong Dae; Song, Gwan Gyu

    2015-11-01

    We examined whether methylenetetrahydrofolate reductase (MTHFR) and glutathione S-transferase (GST) polymorphisms are associated with susceptibility to multiple sclerosis (MS). We performed a meta-analysis on the association between MS and the following genotypes: MTHFR C677T, A1298C, and GSTP1 A313G polymorphisms, and GSTM1 and GSTT1 null alleles. Fifteen comparisons involving 2,486 patients and 2,861 controls were considered. Meta-analysis of all study subjects considered together showed no association between MS and the MTHFR 677 T allele (OR = 1.014, 95 % CI 0.803-1.280, p = 0.909). Stratification by ethnicity showed no similar association in Caucasian and Arab populations. Likewise, no link was found between MS and the MTHFR 1298 C allele in the total data (OR = 2.477, 95 % CI 0.507-12.10, p = 0.263), nor when it was stratified by ethnicity. No association with MS was observed in relation to the GSTM1 null genotype in Caucasian populations (OR = 1.229, 95 % CI 0.693-2.181, p = 0.481), nor with the GSTP1 A313G polymorphism (OR for G allele = 1.133, 95 % CI 0.903-1.421, p = 0.281). However, there was an association between MS and the GSTT1 null genotype in data obtained from Caucasian populations (OR = 1.945, 95 % CI 1.452-2.605, p = 8.6 × 10(-7)). GSTT1 null genotype is associated with MS in Caucasian populations; however, no association was found between MS and polymorphisms of MTHFR, GSTM1, and GSTP1. PMID:26150166

  1. Association of MTHFR A1298C polymorphism with conotruncal heart disease.

    PubMed

    Sayin Kocakap, Beyza D; Sanli, Cihat; Cabuk, Feryal; Koc, Murat; Kutsal, Ali

    2015-10-01

    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. PMID:25547204

  2. Screening of polymorphisms for MTHFR and DHFR genes in spina bifida children and their mothers

    NASA Astrophysics Data System (ADS)

    Husna, M. Z.; Endom, I.; Ibrahim, S.; Selvi, N. Amaramalar; Fakhrurazi, H.; Htwe, R. Ohnmar; Kanehaswari, Y.; Halim, A. R. Abdul; Wong, S. W.; Subashini, K.; Syahira, O. Nur; Aishah, S.

    2013-11-01

    Mechanism underlying the beneficial effect of folic acid supplementation in reducing the risk of neural tube defect is still not well understood. Current evidences show the involvement of folic acid metabolic gene's polymorphism as contributing factors that regulate this pathway. Therefore, the objective of this research was to determine the presence of C677T polymorphism for methylenetetrahydrofolate reductase (MTHFR) and dihydrofolate reductase (DHFR-19 bp deletion) genes between mother-children pairs of case and control. With the approval of UKMMC ethic committee, genomic DNA was extracted from one hundred and forty consented bloods. Polymerase chain reaction (PCR), PCR-RFLP (Restriction Fragment Length Polymorphism) and sequencing were employed to verify each nucleotide change. Our result shows that mutant MTHFR and DHFR alleles are present in all Malaysian sub-ethnic groups, case and control. Even though mutant MTHFR are found to be slightly higher in the case groups, 75% of the affected child is a non carrier for this allele and 62.5% of the mothers with an affected child are genotypically normal. For DHFR, almost all (87.5-100%) investigated samples are a carrier or having a double DHFR deletion be it a case or control pairs. However, strong maternal inheritance shown by the deleted allele might be due to a cascade effect of lacks of folate consumption or maternal uniparental disomy. In conclusion, the use of MTHFR and DHFR as markers in determining the risk of having spina bifida baby is uninformative and plays a small indirect role as the genetic causes of spina bifida. Therefore, spina bifida remains etiologically unknown polygenic and quantitative developmental trait whereby the searches for positive genetic marker need to be continued.

  3. Dihydrofolate-Reductase Mutations in Plasmodium knowlesi Appear Unrelated to Selective Drug Pressure from Putative Human-To-Human Transmission in Sabah, Malaysia

    PubMed Central

    Imwong, Mallika; William, Timothy; Bird, Elspeth; Piera, Kim A.; Aziz, Ammar; Boonyuen, Usa; Drakeley, Christopher J.; Cox, Jonathan; White, Nicholas J.; Cheng, Qin; Yeo, Tsin W.; Auburn, Sarah; Anstey, Nicholas M.

    2016-01-01

    Background Malaria caused by zoonotic Plasmodium knowlesi is an emerging threat in Eastern Malaysia. Despite demonstrated vector competency, it is unknown whether human-to-human (H-H) transmission is occurring naturally. We sought evidence of drug selection pressure from the antimalarial sulfadoxine-pyrimethamine (SP) as a potential marker of H-H transmission. Methods The P. knowlesi dihdyrofolate-reductase (pkdhfr) gene was sequenced from 449 P. knowlesi malaria cases from Sabah (Malaysian Borneo) and genotypes evaluated for association with clinical and epidemiological factors. Homology modelling using the pvdhfr template was used to assess the effect of pkdhfr mutations on the pyrimethamine binding pocket. Results Fourteen non-synonymous mutations were detected, with the most common being at codon T91P (10.2%) and R34L (10.0%), resulting in 21 different genotypes, including the wild-type, 14 single mutants, and six double mutants. One third of the P. knowlesi infections were with pkdhfr mutants; 145 (32%) patients had single mutants and 14 (3%) had double-mutants. In contrast, among the 47 P. falciparum isolates sequenced, three pfdhfr genotypes were found, with the double mutant 108N+59R being fixed and the triple mutants 108N+59R+51I and 108N+59R+164L occurring with frequencies of 4% and 8%, respectively. Two non-random spatio-temporal clusters were identified with pkdhfr genotypes. There was no association between pkdhfr mutations and hyperparasitaemia or malaria severity, both hypothesized to be indicators of H-H transmission. The orthologous loci associated with resistance in P. falciparum were not mutated in pkdhfr. Subsequent homology modelling of pkdhfr revealed gene loci 13, 53, 120, and 173 as being critical for pyrimethamine binding, however, there were no mutations at these sites among the 449 P. knowlesi isolates. Conclusion Although moderate diversity was observed in pkdhfr in Sabah, there was no evidence this reflected selective antifolate drug pressure in humans. PMID:26930493

  4. Molecular Determination of Point Mutation Haplotypes in the Dihydrofolate Reductase and Dihydropteroate Synthase of Plasmodium falciparum in Three Districts of Northern Tanzania

    PubMed Central

    Pearce, Richard J.; Drakeley, Chris; Chandramohan, Daniel; Mosha, Frank; Roper, Cally

    2003-01-01

    The antimalarial combination of sulfadoxine and pyrimethamine (SP) was introduced as first-line treatment for uncomplicated malaria in Tanzania during 2001 following 18 years of second-line use. The genetic determinants of in vitro resistance to the two drugs individually are shown to be point mutations at seven sites in the dihydrofolate reductase gene (dhfr) conferring resistance to pyrimethamine and five sites in the dihydropteroate synthase (dhps) gene conferring resistance to sulfadoxine. Different combinations of mutations within each gene confer differing degrees of insensitivity, but information about the frequency with which allelic haplotypes occur has been lacking because of the complicating effects of multiple infection. Here we used a novel high-throughput sequence-specific oligonucleotide probe-based approach to examine the present resistance status of three Plasmodium falciparum populations in northern Tanzania. By using surveys of asymptomatic infections and screening for the presence of all known point mutations in dhfr and dhps genes, we showed that just five dhfr and three dhps allelic haplotypes are present. High frequencies of both triple-mutant dhfr and double-mutant dhps mutant alleles were found in addition to significant interregional heterogeneity in allele frequency. In vivo studies have shown that the cooccurrence of three dhfr mutations and two dhps mutations in an infection prior to treatment is statistically predictive of treatment failure. We have combined data for both loci to determine the frequency of two-locus genotypes. The triple-dhfr/double-dhps genotype is present in all three regions with frequencies ranging between 30 and 63%, indicating that treatment failure rates are likely to be high. PMID:12654669

  5. Malaria treatment failure with novel mutation in the Plasmodium falciparum dihydrofolate reductase (pfdhfr) gene in Kolkata, West Bengal, India.

    PubMed

    Das, Sabyasachi; Chakraborty, Subhankari Prasad; Hati, AmiyaKumar; Roy, Somenath

    2013-05-01

    The aim of this work was to define the cause of sulfadoxine/pyrimethamine (SP) treatment failure in Plasmodium falciparum infections in a malaria-endemic zone of India. Samples were collected from 176 patients in Kolkata from November 2008 to July 2009. In vitro susceptibility testing was performed on all isolates. Parasite DNA was extracted, and PCR and restriction fragment length polymorphism (RFLP) analysis of different codons of the dhfr gene (16, 51, 59, 108 and 164) and dhps gene (436, 437, 540, 581 and 613) were performed. Finally, sequencing of the products was performed to confirm the mutations. The in vivo treatment response to SP among the 176 patients was determined. A novel mutation of isoleucine was observed at codon 108 of the dhfr gene, which was highly correlated with in vitro SP resistance as well as early treatment failure. A double dhfr mutation (108I+51I) was observed in 77.3% of isolates, and triple mutation of the dhps gene was observed in 18.2% of isolates. In this endemic zone, SP treatment failure is due to a novel dhfr mutation (108I+51I) and any one of the dhps mutations (S436A, A437G, A581G or A613T/S). An increase in these mutations was highly correlated with SP resistance (P < 0.0001). PMID:23428313

  6. Mutations in the Escherichia coli fnr and tgt genes: control of molybdate reductase activity and the cytochrome d complex by fnr.

    PubMed Central

    Frey, B; Jnel, G; Michelsen, U; Kersten, H

    1989-01-01

    In eubacteria, the tRNA transglycosylase (Tgt) in specific tRNAs exchanges a guanine in the anticodon for 7-aminomethyl-7-deazaguanine, which is finally converted to queuosine. The tgt gene of Escherichia coli has been mapped at 9 min on the genome, and mutant pairs containing an intact or mutated tgt allele were obtained after transduction of the tgt locus by P1 bacteriophages into a genetically defined E. coli strain (S. Noguchi, Y. Nishimura, Y. Hirota, and S. Nishimura, J. Biol. Chem. 257:6544-6550, 1982). These tgt mutants grew anerobically with fumarate as an electron acceptor, while nitrate or trimethylamine N-oxide could not be reduced. Furthermore, molybdate reductase activity was almost lacking and the characteristic absorption maxima, corresponding to cytochrome a1 and the cytochrome d complex, were not detectable in low-temperature reduced-minus-oxidized difference spectra in anaerobically grown cells. Transduction of the mutated tgt locus into another E. coli recipient resulted in tgt mutants without anaerobic defects. Transformation of the original tgt mutants with an fnr gene-containing plasmid reversed the anaerobic defects. Clearly, the original tgt mutants harbor a second mutation, affecting the anaerobic regulator protein Fnr. The results suggest that fnr is involved in anaerobic control of components of the cytochrome d complex and of the redox system that transfers electrons to molybdate. F' plasmids containing a fused lacI-lacZ gene with the nonsense codon UAG at different positions in the lacI part were transferred to E. coli strains with a mutated or nonmutated tgt locus but intact in fnr. A twofold increase in the frequency of incorrect readthrough of the UAG codon, dependent on the codon context, was observed in the tgt mutant and is suggested to be caused by a tRNA(Tyr) with G in place of queuosine. PMID:2537821

  7. Plasmodium falciparum: underestimation of dihydrofolate reductase and dihydropteroate synthase polymorphism in field samples: a technical shortcoming of nested PCR assays with mutation-specific primers.

    PubMed

    Chaparro, J; Rojas, M O; Wasserman, M

    2001-11-01

    n a study parallel to the present one, we conducted a genotype characterization of Plasmodium falciparum based on isolates of patients infected with malaria, who come from a small location in Colombia. The analysis involved extraction of DNA from hematological smears, amplification of the dihydrofolate reductase gene and the dihydropteroate synthase (DHPS) gene for each sample by PCR, and detection through mutation-specific primers nested PCR of mutations associated with resistance to pyrimethamine and sulfadoxine. Given the difficulty in quantifying the DNA extracts due to the type of sample and its heterogeneity, different volumes of the product of the first PCR were tested as template for the nested PCR. Surprisingly, for some samples, we found contradictory results between determinations, which differed only in the amount of template used. This prompted a more general concern that in a natural isolate, where the parasite population is heterogeneous, the nested PCR with mutation-specific primers technique can produce erroneous results that underestimate the complexity of the sample. To test this hypothesis, we designed experiments in this study using position 581 of the DHPS gene as an indicator system and constructed samples simulating the heterogeneity of natural samples. In effect, our data show that the results obtained in the nested PCR can be altered by the amount of template used in the reaction and, therefore, some heterogeneous samples might be classified mistakenly as homogeneous, simple mutant or simple wild type. These observations may explain, at least in part, contradictory results found in the literature. Our data also suggest the need for a more cautious approach to interpretation of the results of nested PCR assays with mutation-specific primers and their implications in the definition of resistance to the pyrimethamine-sulfadoxine combination. PMID:11846521

  8. Association between the methylenetetrahydrofolate reductase gene C677T polymorphism and sudden sensorineural hearing loss: a meta-analysis.

    PubMed

    Shu, Jingcheng; Yin, Shihua; Tan, An-Zhou; He, Meirong

    2015-09-01

    A variety of epidemiological studies have evaluated the association between methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism and sudden sensorineural hearing loss (SSNHL), but the results were inconsistent. The aim of this meta-analysis was to clarify more accurately the association of this polymorphism with SSNHL. A systematic literature search of the associated studies up to May 1, 2014, was conducted using the following electronic databases: PubMed, Embase, Medline, and the China National Knowledge Infrastructure. Statistical analyses were performed by STATA12.0 software, with odds ratios (ORs) and their 95 % confidence intervals (CIs). Six eligible studies including covering 1,271 objects were identified. A pooled analysis of these studies showed no significant association between C677T polymorphism and risk of SSNHL: T vs. C (OR = 1.334, POR = 0.105); TT vs. CC (OR = 1.580, POR = 0.231); CT vs. CC (OR = 1.500, POR = 0.123); TT vs. CC + CT (OR = 1.326, POR = 0.293); and TT + CT vs. CC (OR = 1.540, POR = 0.102). But in subgroup analysis, a significant association was found in European populations (T vs. C, OR = 1.542, 95 % CI 1.008-2.359, P = 0.046; TT vs. CT + CC, OR = 1.856, 95 % CI 1.245-2.767, P = 0.002). There was no significant association in any model in the Asian populations. The present meta-analysis suggests that MTHFR gene C677T polymorphism is significantly associated with increased risk of SSNHL disease in European populations, but no statistically significant association was found between the MTHFR C677T gene mutation and SSNHL in Asian. Further large and well-designed studies are needed to confirm this association. PMID:25012704

  9. Meta-analysis of methylenetetrahydrofolate reductase polymorphism and lung cancer risk in Chinese

    PubMed Central

    Wang, Xin; Yue, Kai; Hao, Liran

    2015-01-01

    Numerous studies have investigated association of methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism with lung cancer (LC) susceptibility in Chinese; however, the findings are inconsistent. Therefore, we performed a meta-analysis. PubMed, ISI Web of Knowledge, Chinese National Knowledge Infrastructure, and Wanfang were searched. Pooled ORs and 95% CIs were used to assess the strength of the associations. Overall, 10 studies with 2487 cases and 3228 controls investigating the MTHFR C677T polymorphism and LC risk were included. We did not find a significant association between MTHFR C677T polymorphism and LC risk. However, significantly increased LC risk was found in the population from North China, which was not found in the population from South China. In conclusion, our meta-analysis suggested that MTHFR C677T polymorphism might influence the risk of LC. PMID:25785167

  10. Methylenetetrahydrofolate reductase deficiency alters levels of glutamate and γ-aminobutyric acid in brain tissue

    PubMed Central

    Jadavji, N.M.; Wieske, F.; Dirnagl, U.; Winter, C.

    2015-01-01

    Methylenetetrahydrofolate reductase (MTHFR) is an enzyme key regulator in folate metabolism. Deficiencies in MTHFR result in increased levels of homocysteine, which leads to reduced levels of S-adenosylmethionine (SAM). In the brain, SAM donates methyl groups to catechol-O-methyltransferase (COMT), which is involved in neurotransmitter analysis. Using the MTHFR-deficient mouse model the purpose of this study was to investigate levels of monoamine neurotransmitters and amino acid levels in brain tissue. MTHFR deficiency affected levels of both glutamate and γ-aminobutyric acid in within the cerebellum and hippocampus. Mthfr−/− mice had reduced levels of glutamate in the amygdala and γ-aminobutyric acid in the thalamus. The excitatory mechanisms of homocysteine through activation of the N-methyl-d-aspartate receptor in brain tissue might alter levels of glutamate and γ-aminobutyric acid. PMID:26937386

  11. Short Communication: Lack of association between MTHFR gene polymorphisms and response to methotrexate treatment in Pakistani patients with rheumatoid arthritis.

    PubMed

    Iqbal, Mohammad Perwaiz; Ali, Azra Arif; Mehboobali, Naseema; Iqbal, Khalida

    2015-09-01

    Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms have been reported to be associated with response to methotrexate (MTX) in certain populations of patients with rheumatoid arthritis (RA). This study aims at investigating any relationship of two single nucleotide polymorphisms (SNPs) in MTHFR gene, C677T and A1298C with response to therapy with MTX in Pakistani RA patients. Allelic frequencies of the two polymorphisms (C677T and A1298C) were determined in 67 RA patients (9 males and 58 females; mean age 42.87 ± 13.5 years) who had previously participated in a prospective clinical trial. Fifty-one patients had received MTX and were followed up for response up to 6 months. Genotyping of the two MTHFR polymorphisms was carried out using PCR-RFLP, while fasting concentration of plasma homocysteine was determined using a kit method. Twenty-eight patients were found to be "good responders", while twenty-three were "poor responders". MTHFR 1298C and MTHFR 677T alleles' frequencies in "good responders" were not different from frequencies in "poor responders" (0.574 vs. 0.521; p=0.6 and 0.197 vs. 0.196; p=0.75, respectively). Plasma homocysteine levels in female RA patients were significantly higher compared to general population in Karachi (13.1 ± 6.7 µmol/l vs. 11.4 ± 5.3 µmol/l; p<0.001). MTHFR C677T and A1298C polymorphisms are not associated with response to MTX in a population of Pakistani RA patients. PMID:26408898

  12. MTHFR 677C>T Polymorphism Increases the Male Infertility Risk: A Meta-Analysis Involving 26 Studies

    PubMed Central

    Gong, Mancheng; Dong, Wenjing; He, Tingyu; Shi, Zhirong; Huang, Guiying; Ren, Rui; Huang, Sichong; Qiu, Shaopeng; Yuan, Runqiang

    2015-01-01

    Background and Objectives Methylenetetrahydrofolate reductase (MTHFR) polymorphism may be a risk factor for male infertility. However, the epidemiologic studies showed inconsistent results regarding MTHFR polymorphism and the risk of male infertility. Therefore, we performed a meta-analysis of published case-control studies to re-examine the controversy. Methods Electronic searches of PubMed, EMBASE, Google Scholar and China National Knowledge Infrastructure (CNKI) were conducted to select eligible literatures for this meta-analysis (updated to June 19, 2014). According to our inclusion criteria and the Newcastle-Ottawa Scale (NOS), only high quality studies that observed the association between MTHFR polymorphism and male infertility risk were included. Crude odds ratio (OR) with 95% confidence interval (CI) was used to assess the strength of association between the MTHFR polymorphism and male infertility risk. Results Twenty-six studies involving 5,575 cases and 5,447 controls were recruited. Overall, MTHFR 677C>T polymorphism showed significant associations with male infertility risk in both fixed effects (CT+TT vs. CC: OR = 1.34, 95% CI: 1.23–1.46) and random effects models (CT+TT vs. CC: OR = 1.39, 95% CI: 1.19–1.62). Further, when stratified by ethnicity, sperm concentration and control sources, the similar results were observed in Asians, Caucasians, Azoo or OAT subgroup and both in population-based and hospital-based controls. Nevertheless, no significant association was only observed in oligo subgroup. Conclusions Our results indicated that the MTHFR polymorphism is associated with an increased risk of male infertility. Further well-designed analytical studies are necessary to confirm our conclusions and evaluate gene-environment interactions with male infertility risk. PMID:25793386

  13. Associations of Polymorphisms in MTHFR Gene with the Risk of Age-Related Cataract in Chinese Han Population: A Genotype-Phenotype Analysis

    PubMed Central

    Wei, Li; Han, Ya-di; Cui, Ning-hua; Huang, Zhu-liang; Li, Zu-hua; Zheng, Fang; Yan, Ming

    2015-01-01

    Homocysteine (Hcy) is a potential risk factor for age-related cataract (ARC). Methylenetetrahydrofolate reductase (MTHFR) is the key enzyme for Hcy metabolism, and variants of MTHFR may affect MTHFR enzyme activity. This study mainly evaluated the associations between variants in MTHFR gene, plasma MTHFR enzyme activity, total Hcy (tHcy) levels and ARC risk in Chinese population. Four single nucleotide polymorphisms (SNPs) in MTHFR gene were genotyped using the high-resolution melting (HRM) method in 502 ARC patients (mean age, 70.2 [SD, 9.0], 46.0% male) and 890 healthy controls (mean age, 67.1 [SD, 11.1], 47.6% male). The plasma MTHFR activity, folic acid (FA), vitamins B12 and B6 levels were detected by enzyme-linked immunosorbent assays (ELISA). The plasma tHcy levels were measured by an automated enzymatic assay. After the Bonferroni correction, the minor allele T of SNP rs1801133 showed a significant association with an increased risk of overall ARC (OR = 1.26, P = 0.003). Consistent association was also found between SNP rs1801133 and cortical ARC risk (OR = 1.44, P = 0.003). Haplotype analyses revealed an adverse effect of the haplotype "C-A-T-C" (alleles in order of SNPs rs3737967, rs1801131, rs1801133 and rs9651118) on ARC risk (OR = 1.55, P = 0.003). Moreover, in a joint analysis of SNPs rs9651118 and rs1801133, subjects with two unfavorable genotypes had a 1.76-fold increased risk of ARC compared with the reference group, and a statistically significant dose-response trend (Ptrend = 0.001) was also observed. Further, in healthy controls and patients with cortical ARC, the allele T of SNP rs1801133 and the increasing number of unfavorable genotypes were significantly correlated with decreased MTHFR activity as well as increased tHcy levels. However, there was no significant association between FA, vitamins B12, B6 levels and MTHFR variants. Our data indicated that variants in MTHFR gene might individually and jointly influence susceptibility to ARC by affecting MTHFR enzyme activity and tHcy levels. PMID:26689687

  14. Associations of Polymorphisms in MTHFR Gene with the Risk of Age-Related Cataract in Chinese Han Population: A Genotype-Phenotype Analysis.

    PubMed

    Wang, Xue-Bin; Qiao, Chen; Wei, Li; Han, Ya-di; Cui, Ning-Hua; Huang, Zhu-Liang; Li, Zu-Hua; Zheng, Fang; Yan, Ming

    2015-01-01

    Homocysteine (Hcy) is a potential risk factor for age-related cataract (ARC). Methylenetetrahydrofolate reductase (MTHFR) is the key enzyme for Hcy metabolism, and variants of MTHFR may affect MTHFR enzyme activity. This study mainly evaluated the associations between variants in MTHFR gene, plasma MTHFR enzyme activity, total Hcy (tHcy) levels and ARC risk in Chinese population. Four single nucleotide polymorphisms (SNPs) in MTHFR gene were genotyped using the high-resolution melting (HRM) method in 502 ARC patients (mean age, 70.2 [SD, 9.0], 46.0% male) and 890 healthy controls (mean age, 67.1 [SD, 11.1], 47.6% male). The plasma MTHFR activity, folic acid (FA), vitamins B12 and B6 levels were detected by enzyme-linked immunosorbent assays (ELISA). The plasma tHcy levels were measured by an automated enzymatic assay. After the Bonferroni correction, the minor allele T of SNP rs1801133 showed a significant association with an increased risk of overall ARC (OR = 1.26, P = 0.003). Consistent association was also found between SNP rs1801133 and cortical ARC risk (OR = 1.44, P = 0.003). Haplotype analyses revealed an adverse effect of the haplotype "C-A-T-C" (alleles in order of SNPs rs3737967, rs1801131, rs1801133 and rs9651118) on ARC risk (OR = 1.55, P = 0.003). Moreover, in a joint analysis of SNPs rs9651118 and rs1801133, subjects with two unfavorable genotypes had a 1.76-fold increased risk of ARC compared with the reference group, and a statistically significant dose-response trend (Ptrend = 0.001) was also observed. Further, in healthy controls and patients with cortical ARC, the allele T of SNP rs1801133 and the increasing number of unfavorable genotypes were significantly correlated with decreased MTHFR activity as well as increased tHcy levels. However, there was no significant association between FA, vitamins B12, B6 levels and MTHFR variants. Our data indicated that variants in MTHFR gene might individually and jointly influence susceptibility to ARC by affecting MTHFR enzyme activity and tHcy levels. PMID:26689687

  15. MTHFR gene polymorphism and risk of myeloid leukemia: a meta-analysis.

    PubMed

    Dong, Song; Liu, Yueling; Chen, Jieping

    2014-09-01

    An increasing body of evidence has shown that the amino acid changes at position 1298 might eliminate methylenetetrahydrofolate reductase (MTHFR) enzyme activity, leading to insufficient folic acid and subsequent human chromosome breakage. Epidemiological studies have linked MTHFR single-nucleotide polymorphism (SNP) rs1801131 to myeloid leukemia risk, with considerable discrepancy in their results. We therefore were prompted to clarify this issue by use of a meta-analysis. The search terms were used to cover the possible reports in the MEDLINE, Web of Knowledge, and China National Knowledge Infrastructure (CNKI) databases. Odds ratios were estimated to assess the association of SNP rs1801131 with myeloid leukemia risk. Statistical heterogeneity was detected using the Q-statistic and I (2) metric. Subgroup analysis was performed by ethnicity, histological subtype, and Hardy-Weinberg equilibrium (HWE). This meta-analysis of eight publications with a total of 1,114 cases and 3,227 controls revealed no global association. Nor did the subgroup analysis according to histological subtype and HWE show any significant associations. However, Asian individuals who harbored the CC genotype were found to have 1.66-fold higher risk of myeloid leukemia (odds ratio, 1.66; 95 % confidence interval, 1.10 to 2.49; P h = 0.342; I (2) = 0.114). Our meta-analysis has presented evidence supporting a possible association between the CC genotype of MTHFR SNP rs1801131 and myeloid leukemia in Asian populations. PMID:24894669

  16. High homocysteine and epistasis between MTHFR and APOE: association with cognitive performance in the elderly.

    PubMed

    Polito, Letizia; Poloni, Tino Emanuele; Vaccaro, Roberta; Abbondanza, Simona; Mangieri, Michela; Davin, Annalisa; Villani, Simona; Guaita, Antonio

    2016-04-01

    High total homocysteine (tHcy) is associated with cognitive impairment in the elderly. The impact of high tHcy on different cognitive domains deserves further investigation, as does the role of the C677T polymorphism of the 5,10 methylenetetrahydrofolate reductase (MTHFR) gene. A cross-sectional analysis of 903 subjects from the population-based "InveCe.Ab" study was performed. The participants had no psychosis or active neurological disorders. They underwent a neuropsychological assessment. Principal component analysis allowed cognitive performance to be condensed into two components: executive functions and memory. Novel components were evaluated for association with tHcy, controlling for potential confounders. Regression models showed that high serum tHcy was associated with lower executive functions, but not with memory. MTHFR C677T TT was associated with higher tHcy but did not affect cognitive performance per se. However, when combined with the apolipoprotein E (APOE)-ε4 allele, it was a risk factor for lower executive performance, independently of tHcy levels. In summary, high tHcy per se, or MTHFR C677T TT in combination with the APOE-ε4 allele, might be associated primarily with executive dysfunctions rather than memory loss. PMID:26774227

  17. Identification of three new mutations in the NADH-cytochrome b5 reductase gene responsible for recessive congenital methemoglobinemia type II

    SciTech Connect

    Mota-Vieira, L.; Kaplan, J.C.; Kahn, A.; Leroux, A.

    1994-09-01

    Recessive congenital methemoglobinemia (RCM; McKusick N{degrees}25800) due to NADH-cytochrome b5 reductase (cytb5r) deficiency leads to two different types of diseases: in type I form, cyanosis is the only symptom and the enzyme is only defective in red blood cells; in type II form, cyanosis is associated with severe mental retardation and neurological impairment and the enzyme defect is systemic. We have identified three new molecular defects in two unrelated patients with type II RCM. A homozygous C{r_arrow}T transition in codon 218 (Arg) was detected in the cDNA of one patient, resulting in a premature stop codon (TGA) in exon 8. Restriction enzyme analysis of genomic DNA confirmed the homozygosity of the propositus and heterozygosity for an identical defect in both parents. The second patient was found to be a compound heterozygote, carrying two different mutant alleles in the cyb5r gene. One allele presented a missense mutation (T{r_arrow}C) with substitution of Cys-203 (TGC) by Arg (CGC) in exon 7. The second allele showed a 3 bp deletion of nucleotides 815-817 of the cDNA. The CTG ATG sequence at position 814-819 in exon 9 coding for Leu-271 and Met-272 was replaced by the CTG triplet, with conservation of the Leu-271 and loss of the Met-272. To our knowledge, these are the first examples of a homozygous nonsense mutation and of a compound heterozygous mutation detected in the cytb5r gene. This finding supports the diversity of genetic defects in the cytb5r gene leading to the severe form of the disease.

  18. Spectrum of MTHFR gene SNPs C677T and A1298C: a study among 23 population groups of India.

    PubMed

    Saraswathy, Kallur Nava; Asghar, Mohammad; Samtani, Ratika; Murry, Benrithung; Mondal, Prakash Ranjan; Ghosh, Pradeep Kumar; Sachdeva, Mohinder Pal

    2012-04-01

    Elevated homocysteine is a risk factor for many complex disorders. The role of methylenetetrahydrofolate reductase (MTHFR) gene in methylation of homocysteine makes it one of the most important candidate genes for these disorders. Considering the heterogeneity in its distribution in world populations, we screened MTHFR C677T and A1298C single nucleotide polymorphisms in a total of 23 Indian caste, tribal and religious population groups from five geographical regions of India and belonging to four major linguistic groups. The frequencies of MTHFR 677T and 1298C alleles were found to be 10.08 and 20.66%, respectively. MTHFR homozygous genotype 677TT was absent in eight population groups and homozygous 1298CC was absent in two population groups. 677T allele was found to be highest among north Indian populations with Indo-European tongue and 1298C was high among Dravidian-speaking tribes of east India and south India. The less common mutant haplotype 677T-1298C was observed among seven population groups and overall the frequency of this haplotype was 0.008, which is similar to that of African populations. cis configuration of 677T and 1298C was 0.94%. However, we could not find any individual with four mutant alleles which supports the earlier observation that presence of more than two mutant alleles may decrease the viability of foetus and possibly be a selective disadvantage in the population. PMID:22147263

  19. Contribution of GSTM1, GSTT1, and MTHFR polymorphisms to end-stage renal disease of unknown etiology in Mexicans.

    PubMed

    Gutiérrez-Amavizca, B E; Orozco-Castellanos, R; Ortíz-Orozco, R; Padilla-Gutiérrez, J; Valle, Y; Gutiérrez-Gutiérrez, N; García-García, G; Gallegos-Arreola, M; Figuera, L E

    2013-11-01

    Oxidative stress is increased in chronic kidney disease, owing to an imbalance between the oxidative and antioxidant pathways as well as a state of persistent hyperhomocysteinemia. The enzymes glutathione S-transferases (GSTs) and methylenetetrahydrofolate reductase (MTHFR) are implicated in the regulation of these pathways. This study investigates the association between polymorphisms in the Glutathione S-transferase Mu 1 (GSTM1), glutathione S-transferase theta 1 (GSTT1), and MTHFR genes and end-stage renal disease (ESRD) of unknown etiology in patients in Mexico. A Case-control study included 110 ESRD patients and 125 healthy individuals. GSTM1 and GSTT1 genotypes were determined using the multiplex polymerase chain reaction (PCR). The MTHFR C677T polymorphism was studied using a PCR/restriction fragment length polymorphism method. In ESRD patients, GSTM1 and GSTT1 null genotype frequencies were 61% and 7% respectively. GSTM1 genotype frequencies differed significantly between groups, showing that homozygous deletion of the GSTM1 gene was associated with susceptibility to ESRD of unknown etiology (P = 0.007, odds ratios = 2.05, 95% confidence interval 1.21-3.45). The MTHFR C677T polymorphism genotype and allele distributions were similar in both groups (P > 0.05), and the CT genotype was the most common genotype in both groups (45.5% and 46.6%). Our findings suggest that the GSTM1 null polymorphism appears to be associated with the ESRD of unknown etiology in patients in Mexico. PMID:24339523

  20. SHMT1 1420 and MTHFR 677 variants are associated with rectal but not colon cancer

    PubMed Central

    2010-01-01

    Background Association between rectal or colon cancer risk and serine hydroxymethyltransferase 1 (SHMT1) C1420T or methylenetetrahydrofolate reductase (MTHFR) C677T polymorphisms was assessed. The serum total homocysteine (HCY), marker of folate metabolism was also investigated. Methods The SHMT1 and MTHFR genotypes were determined by real-time PCR and PCR-RFLP, respectively in 476 patients with rectal, 479 patients with colon cancer and in 461 and 478, respective controls matched for age and sex. Homocysteine levels were determined by HPLC kit. The association between polymorphisms and cancer risk was evaluated by logistic regression analysis adjusted for age, sex and body mass index. The population stratification bias was also estimated. Results There was no association of genotypes or diplotypes with colon cancer. The rectal cancer risk was significantly lower for SHMT1 TT (OR = 0.57, 95% confidence interval (CI) 0.36-0.89) and higher for MTHFR CT genotypes (OR = 1.4, 95%CI 1.06-1.84). A gene-dosage effect was observed for SHMT1 with progressively decreasing risk with increasing number of T allele (p = 0.014). The stratified analysis according to age and sex revealed that the association is mainly present in the younger (< 60 years) or male subgroup. As expected from genotype analysis, the SHMT1 T allele/MTHFR CC diplotype was associated with reduced rectal cancer risk (OR 0.56, 95%CI 0.42-0.77 vs all other diplotypes together). The above results are unlikely to suffer from population stratification bias. In controls HCY was influenced by SHMT1 polymorphism, while in patients it was affected only by Dukes' stage. In patients with Dukes' stage C or D HCY can be considered as a tumor marker only in case of SHMT1 1420CC genotypes. Conclusions A protective effect of SHMT1 1420T allele or SHMT1 1420 T allele/MTHFR 677 CC diplotype against rectal but not colon cancer risk was demonstrated. The presence of SHMT1 1420 T allele significantly increases the HCY levels in controls but not in patients. Homocysteine could be considered as a tumor marker in SHMT1 1420 wild-type (CC) CRC patients in Dukes' stage C and D. Further studies need to clarify why SHMT1 and MTHFR polymorphisms are associated only with rectal and not colon cancer risk. PMID:20920350

  1. Significant Impact of the MTHFR Polymorphisms and Haplotypes on Male Infertility Risk

    PubMed Central

    Gupta, Nishi; Sarkar, Saumya; David, Archana; Gangwar, Pravin Kumar; Gupta, Richa; Khanna, Gita; Sankhwar, Satya Narayan; Khanna, Anil; Rajender, Singh

    2013-01-01

    Background Methylenetetrahydrofolate reductase (MTHFR) converts 5,10-methylene tetrahydrofolate to 5-methyl tetrahydrofolate and affects the activity of cellular cycles participating in nucleotide synthesis, DNA repair, genome stability, maintenance of methyl pool, and gene regulation. Genetically compromised MTHFR activity has been suggested to affect male fertility. The objective of the present study was to find the impact on infertility risk of c.203G>A, c.1298A>C, and c.1793G>A polymorphisms in the MTHFR gene. Methods PCR-RFLP and DNA sequencing were used to genotype the common SNPs in the MTHFR gene in 630 infertile and 250 fertile males. Chi-square test was applied for statistical comparison of genotype data. Linkage disequilibrium between the SNPs and the frequency of common haplotypes were assessed using Haploview software. Biochemical levels of total homocysteine (tHcy) and folic acid were measured. Meta-analysis on c.1298A>C polymorphism was performed using data from ten studies, comprising 2734 cases and 2737 controls. Results c.203G>A and c.1298A>C were found to be unrelated to infertility risk. c.1793G>A was protective against infertility (P = 0.0008). c.677C>T and c.1793G>A were in significant LD (D’ = 0.9). Folic acid and tHcy level did not correlate with male infertility. Pooled estimate on c.1298A>C data from all published studies including our data showed no association of this polymorphism with male infertility (Odds ratio = 1.035, P = 0.56), azoospermia (Odds ratio = 0.97, P = 0.74), or oligoasthenoteratozoospermia (Odds ratio = 0.92, p = 0.29). Eight haplotypes with more than 1% frequency were detected, of which CCGA was protective against infertility (p = 0.02), but the significance of the latter was not seen after applying Bonferroni correction. Conclusion Among MTHFR polymorphisms, c.203G>A and c.1298A>C do not affect infertility risk and c.1793G>A is protective against infertility. Haplotype analysis suggested that risk factors on the MTHFR locus do not extend too long on the DNA string. PMID:23874907

  2. Risk association of meningiomas with MTHFR C677T and GSTs polymorphisms: a meta-analysis.

    PubMed

    Ding, Hao; Liu, Wei; Yu, Xinyuan; Wang, Lei; Shao, Lingmin; Yi, Wei

    2014-01-01

    Previous studies have shown that the single nucleotide polymorphisms (SNPs) in Methylenetetrahydrofolate reductase (MTHFR) and Glutathione S-transferases (GSTs, including GSTM1, GSTT1) genes play an important role in determining the response of an individual to environmental pathogenesis and significantly relate to incidences of various human tumors, including brain tumors. However, these genes' polymorphisms on meningioma risk remains poorly understood. The relevant inferences from previous studies are hindered by their limited statistical power and conflicting results. The aim of this meta-analysis is to provide a relatively comprehensive account of the association between these polymorphisms and human meningioma risk. A literature search for eligible studies published before January 1, 2014 was conducted in PubMed, Embase, Web of Science, Cochrane Library, and CNKI databases. Pooled odds ratios (OR) with their corresponding 95% confidence intervals (95% CI) were used to evaluate the strength of the association under a fixed or random effect model according to heterogeneity test results. Heterogeneity and publication bias were evaluated. All statistical analyses were conducted by using the software of STATA 12.0 (STATA Corporation, College Station, TX, USA). For MTHFR C677T (dbSNP: rs1801133) (C T) polymorphism, 9 individual case-control studies from six publications with 1,615 cases and 1,909 controls were obtained. For GSTM1 null polymorphism, there were 4 studies with 417 cases and 1,735 controls. For GSTT1 null polymorphism, there were 4 studies with 405 cases and 1,622 controls. The combined results for the MTHFR C677T show that carriers of the CT genotype may be associated with a higher meningioma risk (OR = 1.20, 95% CI 1.05-1.38, P = 0.009). Stratified analyses show that Caucasians have significantly higher risk if they carry the CT genotype of MTHFR (OR = 1.31, 95% CI 1.05-1.63, P = 0.02). Risk of Caucasians carrying TT + CT genotype is also significantly higher (OR = 1.27, 95% CI 1.02-1.58, P = 0.03). Risk of Caucasians carrying TT genotype is not significantly different compared to control population (OR = 0.96, 95% CI 0.69-1.34, P = 0.82). All of the enrolled studies about GSTM1/GSTT1 are on Caucasians. The pooled ORGSTM1 and ORGSTT1 were not significant in Caucasian population. These results indicate SNPs of MTHFR C677T are related to meningioma risk with ethnic differences. Caucasians carrying CT genotype of MTHFR C677T have significantly higher meningioma susceptibility. SNPs of GSTM1/GSTT1 are not related to meningioma risk. PMID:25550898

  3. Quantification of gene-specific methylation of DNMT3B and MTHFR using sequenom EpiTYPER®

    PubMed Central

    Ho, Vikki; Ashbury, Janet E.; Taylor, Sherryl; Vanner, Stephen; King, Will D.

    2015-01-01

    Among 272 patients undergoing a screening colonoscopy, DNA methylation of DNMT3B and MTHFR, genes encoding enzymes critical to one-carbon metabolism, was quantified in blood leukocytes using Sequenom EpiTYPER®. DNA methylation was quantified in 66 and 28 CpG sites of DNMT3B and MTHFR respectively, and conceptualized using two approaches. First, measures representing average methylation across all CpG sites were created. Second, unsupervised principal component (PC) analysis was used as a pattern derivation and data-reduction approach, to develop two summary variables (PC1 and PC2). These two summary variables represented methylation around the transcription start site (PC1) and in the gene-coding area (PC2) for both DNMT3B and MTHFR. The data contained in this article presents the variation of methylation levels for individual CpG sites within the DNMT3B and MTHFR genes and possible correlations uncovered using PC analysis. The data are related to the research article “Gene-specific DNA methylation of DNMT3B and MTHFR and colorectal adenoma risk” in Mutation Research – Fundamental and Molecular Mechanisms of Mutagenesis. PMID:26759827

  4. Quantification of gene-specific methylation of DNMT3B and MTHFR using sequenom EpiTYPER®.

    PubMed

    Ho, Vikki; Ashbury, Janet E; Taylor, Sherryl; Vanner, Stephen; King, Will D

    2016-03-01

    Among 272 patients undergoing a screening colonoscopy, DNA methylation of DNMT3B and MTHFR, genes encoding enzymes critical to one-carbon metabolism, was quantified in blood leukocytes using Sequenom EpiTYPER®. DNA methylation was quantified in 66 and 28 CpG sites of DNMT3B and MTHFR respectively, and conceptualized using two approaches. First, measures representing average methylation across all CpG sites were created. Second, unsupervised principal component (PC) analysis was used as a pattern derivation and data-reduction approach, to develop two summary variables (PC1 and PC2). These two summary variables represented methylation around the transcription start site (PC1) and in the gene-coding area (PC2) for both DNMT3B and MTHFR. The data contained in this article presents the variation of methylation levels for individual CpG sites within the DNMT3B and MTHFR genes and possible correlations uncovered using PC analysis. The data are related to the research article "Gene-specific DNA methylation of DNMT3B and MTHFR and colorectal adenoma risk" in Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis. PMID:26759827

  5. The MTHFR C677T Polymorphism and Risk of Intracerebral Hemorrhage in a Chinese Han Population.

    PubMed

    Hu, Xin; Tao, Chuanyuan; Xie, Zhiyi; Li, Yunke; Zheng, Jun; Fang, Yuan; Lin, Sen; Li, Hao; You, Chao

    2016-01-01

    BACKGROUND Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism has been speculated to be and extensively investigated as a risk factor for various vascular diseases, including intracerebral hemorrhage (ICH). However, results from published studies regarding the role of C677T polymorphism in ICH risk in Chinese populations were contradictory rather than conclusive. MATERIAL AND METHODS In this study, a total of 180 ICH patients and 180 matched controls of Chinese Han ethnicity were enrolled. The MTHFR C677T polymorphism was genotyped by polymerase chain reaction-ligation detection reaction (PCR-LDR). A meta-analysis was conducted by combining our data with previous relevant studies in Chinese populations. RESULTS In our case-control study, similar allele frequency (p=0.492) and genotype distribution (p=0.748) of MTHFR C677T polymorphism were detected between ICH patients and controls. Further analysis based on hematoma location did not show a significant association. When combined with previous studies, however, C677T polymorphism was found to be significantly associated with an increased risk for ICH in Chinese populations (recessive model: OR=1.57, 95%CI=1.29-1.91). When focusing on the Han ethnicity, carriers of the TT genotype had an increased risk of ICH (recessive model: OR=1.36, 95%CI=1.05-1.75). CONCLUSIONS In this case-control study we did not observe that the MTHFR C677T polymorphism was associated with ICH risk in people of Chinese Han ethnicity. However, when combined with previous published studies, a significant association of C677T polymorphism with an increased risk of ICH was detected in Chinese populations, and also in the subgroup analysis focusing on Han ethnicity. PMID:26757363

  6. Meta-analysis of the association of MTHFR polymorphisms with multiple myeloma risk.

    PubMed

    Ma, Li-Min; Ruan, Lin-Hai; Yang, Hai-Ping

    2015-01-01

    The association of methylenetetrahydrofolate reductase (MTHFR) polymorphisms with multiple myeloma (MM) risk has been explored, but the results remain controversial. Thus, a meta-analysis was performed to provide a comprehensively estimate. The case-control studies about MTHFR C677T and A1298C polymorphisms with MM risk were collected by searching PubMed, Elsevier, China National Knowledge Infrastructure and Wanfang Databases. Odds ratios (ORs) with 95% confidence intervals (CIs) were applied to assess the strength of association. Overall, no significant association was found between MTHFR A1298C polymorphism and MM risk under all four genetic models (AC vs. AA, OR = 0.99, 95%CI = 0.82-1.20; CC vs. AA, OR = 1.14, 95%CI = 0.77-1.68; recessive model, OR = 1.10, 95%CI = 0.76-1.59; dominant model, OR = 1.01, 95%CI = 0.84-1.22). The risk was also not significantly altered for C677T polymorphism and MM in overall comparisons (CT vs. CC, OR = 1.04, 95%CI = 0.93-1.17; TT vs. CC, OR = 1.16, 95%CI = 0.98-1.37; recessive model, OR = 1.13, 95%CI = 0.98-1.32; dominant model, OR = 1.07, 95%CI = 0.96-1.20). In subgroup analyses by ethnicity, no significant association was observed in both Caucasians and Asians. This meta-analysis suggested that MTHFR polymorphisms were not associated with MM risk. PMID:26022785

  7. Meta-analysis of the association of MTHFR polymorphisms with multiple myeloma risk

    PubMed Central

    Ma, Li-Min; Ruan, Lin-Hai; Yang, Hai-Ping

    2015-01-01

    The association of methylenetetrahydrofolate reductase (MTHFR) polymorphisms with multiple myeloma (MM) risk has been explored, but the results remain controversial. Thus, a meta-analysis was performed to provide a comprehensively estimate. The case-control studies about MTHFR C677T and A1298C polymorphisms with MM risk were collected by searching PubMed, Elsevier, China National Knowledge Infrastructure and Wanfang Databases. Odds ratios (ORs) with 95% confidence intervals (CIs) were applied to assess the strength of association. Overall, no significant association was found between MTHFR A1298C polymorphism and MM risk under all four genetic models (AC vs. AA, OR = 0.99, 95%CI = 0.82-1.20; CC vs. AA, OR = 1.14, 95%CI = 0.77-1.68; recessive model, OR = 1.10, 95%CI = 0.76-1.59; dominant model, OR = 1.01, 95%CI = 0.84-1.22). The risk was also not significantly altered for C677T polymorphism and MM in overall comparisons (CT vs. CC, OR = 1.04, 95%CI = 0.93-1.17; TT vs. CC, OR = 1.16, 95%CI = 0.98-1.37; recessive model, OR = 1.13, 95%CI = 0.98-1.32; dominant model, OR = 1.07, 95%CI = 0.96-1.20). In subgroup analyses by ethnicity, no significant association was observed in both Caucasians and Asians. This meta-analysis suggested that MTHFR polymorphisms were not associated with MM risk. PMID:26022785

  8. The MTHFR C677T Polymorphism and Risk of Intracerebral Hemorrhage in a Chinese Han Population

    PubMed Central

    Hu, Xin; Tao, Chuanyuan; Xie, Zhiyi; Li, Yunke; Zheng, Jun; Fang, Yuan; Lin, Sen; Li, Hao; You, Chao

    2016-01-01

    Background Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism has been speculated to be and extensively investigated as a risk factor for various vascular diseases, including intracerebral hemorrhage (ICH). However, results from published studies regarding the role of C677T polymorphism in ICH risk in Chinese populations were contradictory rather than conclusive. Material/Methods In this study, a total of 180 ICH patients and 180 matched controls of Chinese Han ethnicity were enrolled. The MTHFR C677T polymorphism was genotyped by polymerase chain reaction-ligation detection reaction (PCR-LDR). A meta-analysis was conducted by combining our data with previous relevant studies in Chinese populations. Results In our case-control study, similar allele frequency (p=0.492) and genotype distribution (p=0.748) of MTHFR C677T polymorphism were detected between ICH patients and controls. Further analysis based on hematoma location did not show a significant association. When combined with previous studies, however, C677T polymorphism was found to be significantly associated with an increased risk for ICH in Chinese populations (recessive model: OR=1.57, 95%CI=1.29–1.91). When focusing on the Han ethnicity, carriers of the TT genotype had an increased risk of ICH (recessive model: OR=1.36, 95%CI=1.05–1.75). Conclusions In this case-control study we did not observe that the MTHFR C677T polymorphism was associated with ICH risk in people of Chinese Han ethnicity. However, when combined with previous published studies, a significant association of C677T polymorphism with an increased risk of ICH was detected in Chinese populations, and also in the subgroup analysis focusing on Han ethnicity. PMID:26757363

  9. New insights into the catalytic mechanism of vitamin K epoxide reductase (VKORC1) - The catalytic properties of the major mutations of rVKORC1 explain the biological cost associated to mutations.

    PubMed

    Matagrin, Benjamin; Hodroge, Ahmed; Montagut-Romans, Adrien; Andru, Julie; Fourel, Isabelle; Besse, Stéphane; Benoit, Etienne; Lattard, Virginie

    2013-01-01

    The systematic use of antivitamin K anticoagulants (AVK) as rodenticides caused the selection of rats resistant to AVKs. The resistance is mainly associated to genetic polymorphisms in the Vkorc1 gene encoding the VKORC1 enzyme responsible for the reduction of vitamin K 2,3-epoxide to vitamin K. Five major mutations, which are responsible for AVK resistance, have been described. Possible explanations for the biological cost of these mutations have been suggested. This biological cost might be linked to an increase in the vitamin K requirements. To analyze the possible involvement of VKORC1 in this biological cost, rVKORC1 and its major mutants were expressed in Pichia pastoris as membrane-bound proteins and their catalytic properties were determined for vitamin K and 3-OH-vitamin K production. In this report, we showed that mutations at Leu-120 and Tyr-139 dramatically affect the vitamin K epoxide reductase activity. Moreover, this study allowed the detection of an additional production of 3-hydroxyvitamin K for all the mutants in position 139. This result suggests the involvement of Tyr-139 residue in the second half-step of the catalytic mechanism corresponding to the dehydration of vitamin K epoxide. As a consequence, the biological cost observed in Y139C and Y139S resistant rat strains is at least partially explained by the catalytic properties of the mutated VKORC1 involving a loss of vitamin K from the vitamin K cycle through the formation of 3-hydroxyvitamin K and a very low catalytic efficiency of the VKOR activity. PMID:23772386

  10. Contraception-related deep venous thrombosis and pulmonary embolism in a 17-Year-old girl heterozygous for factor V leiden, prothrombin G20210A mutation, MTHFR C677T and homozygous for PAI-1 mutation: report of a family with multiple genetic risk factors and review of the literature.

    PubMed

    Lenicek Krleza, Jasna; Jakovljevic, Gordana; Bronic, Ana; Coen Herak, Désirée; Bonevski, Aleksandra; Stepan-Giljevic, Jasminka; Roic, Goran

    2010-01-01

    We present the case of a 17-year-old girl who suddenly woke up with localized pain in the left groin and the inability to twist her leg. After comprehensive physician and laboratory examinations, deep venous thrombosis with consequent pulmonary embolism was ascertained. She had not experienced any recent trauma, but she had started to take oral contraceptives 6 months prior to the onset of the symptoms. Her parents and sisters had been asymptomatic throughout their lives, but the family history revealed a few thromboembolic accidents. Using DNA analysis, heterozygosity for factor V Leiden, prothrombin gene mutation G20210A and methylenetetrahydrofolate reductase C677T, as well as the homozygous 4G/4G genotype in the plasminogen activator inhibitor 1 were identified in our patient. Subsequently, DNA analysis was performed in all living family members, and multiple factors associated with thrombophilia were discovered. Our case confirms the multifactorial cause of thromboembolic events and emphasizes the importance of oral contraceptive use in the onset of venous thrombosis, especially in teenage females. In addition, this case indicates that teenage females with a family history of thrombosis who are making choices about contraception could most likely benefit from advanced thrombophilia testing. PMID:20664190

  11. MTHFR deficiency or reduced intake of folate or choline in pregnant mice results in impaired short-term memory and increased apoptosis in the hippocampus of wild-type offspring.

    PubMed

    Jadavji, N M; Deng, L; Malysheva, O; Caudill, M A; Rozen, R

    2015-08-01

    Genetic or nutritional disturbances in one-carbon metabolism, with associated hyperhomocysteinemia, can result in complex disorders including pregnancy complications and neuropsychiatric diseases. In earlier work, we showed that mice with a complete deficiency of methylenetetrahydrofolate reductase (MTHFR), a critical enzyme in folate and homocysteine metabolism, had cognitive impairment with disturbances in choline metabolism. Maternal demands for folate and choline are increased during pregnancy and deficiencies of these nutrients result in several negative outcomes including increased resorption and delayed development. The goal of this study was to investigate the behavioral and neurobiological impact of a maternal genetic deficiency in MTHFR or maternal nutritional deficiency of folate or choline during pregnancy on 3-week-old Mthfr(+/+) offspring. Mthfr(+/+) and Mthfr(+/-) females were placed on control diets (CD); and Mthfr(+/+) females were placed on folate-deficient diets (FD) or choline-deficient diets (ChDD) throughout pregnancy and lactation until their offspring were 3weeks of age. Short-term memory was assessed in offspring, and hippocampal tissue was evaluated for morphological changes, apoptosis, proliferation and choline metabolism. Maternal MTHFR deficiency resulted in short-term memory impairment in offspring. These dams had elevated levels of plasma homocysteine when compared with wild-type dams. There were no differences in plasma homocysteine in offspring. Increased apoptosis and proliferation was observed in the hippocampus of offspring from Mthfr(+/-) mothers. In the maternal FD and ChDD study, offspring also showed short-term memory impairment with increased apoptosis in the hippocampus; increased neurogenesis was observed in ChDD offspring. Choline acetyltransferase protein was increased in the offspring hippocampus of both dietary groups and betaine was decreased in the hippocampus of FD offspring. Our results reveal short-term memory deficits in the offspring of dams with MTHFR deficiency or dietary deficiencies of critical methyl donors. We suggest that deficiencies in maternal one-carbon metabolism during pregnancy can contribute to hippocampal dysfunction in offspring through apoptosis or altered choline metabolism. PMID:25956258

  12. Mutation of the Inducible ARABIDOPSIS THALIANA CYTOCHROME P450 REDUCTASE2 Alters Lignin Composition and Improves Saccharification1[W][OPEN

    PubMed Central

    Sundin, Lisa; Vanholme, Ruben; Geerinck, Jan; Goeminne, Geert; Höfer, René; Kim, Hoon; Ralph, John; Boerjan, Wout

    2014-01-01

    ARABIDOPSIS THALIANA CYTOCHROME P450 REDUCTASE1 (ATR1) and ATR2 provide electrons from NADPH to a large number of CYTOCHROME P450 (CYP450) enzymes in Arabidopsis (Arabidopsis thaliana). Whereas ATR1 is constitutively expressed, the expression of ATR2 appears to be induced during lignin biosynthesis and upon stresses. Therefore, ATR2 was hypothesized to be preferentially involved in providing electrons to the three CYP450s involved in lignin biosynthesis: CINNAMATE 4-HYDROXYLASE (C4H), p-COUMARATE 3-HYDROXYLASE1 (C3H1), and FERULATE 5-HYDROXYLASE1 (F5H1). Here, we show that the atr2 mutation resulted in a 6% reduction in total lignin amount in the main inflorescence stem and a compositional shift of the remaining lignin to a 10-fold higher fraction of p-hydroxyphenyl units at the expense of syringyl units. Phenolic profiling revealed shifts in lignin-related phenolic metabolites, in particular with the substrates of C4H, C3H1 and F5H1 accumulating in atr2 mutants. Glucosinolate and flavonol glycoside biosynthesis, both of which also rely on CYP450 activities, appeared less affected. The cellulose in the atr2 inflorescence stems was more susceptible to enzymatic hydrolysis after alkaline pretreatment, making ATR2 a potential target for engineering plant cell walls for biofuel production. PMID:25315601

  13. A mutated xylose reductase increases bioethanol production more than a glucose/xylose facilitator in simultaneous fermentation and co-fermentation of wheat straw

    PubMed Central

    2011-01-01

    Genetically engineered Saccharomyces cerevisiae strains are able to ferment xylose present in lignocellulosic biomass. However, better xylose fermenting strains are required to reach complete xylose uptake in simultaneous saccharification and co-fermentation (SSCF) of lignocellulosic hydrolyzates. In the current study, haploid Saccharomyces cerevisiae strains expressing a heterologous xylose pathway including either the native xylose reductase (XR) from P. stipitis, a mutated variant of XR (mXR) with altered co-factor preference, a glucose/xylose facilitator (Gxf1) from Candida intermedia or both mXR and Gxf1 were assessed in SSCF of acid-pretreated non-detoxified wheat straw. The xylose conversion in SSCF was doubled with the S. cerevisiae strain expressing mXR compared to the isogenic strain expressing the native XR, converting 76% and 38%, respectively. The xylitol yield was less than half using mXR in comparison with the native variant. As a result of this, the ethanol yield increased from 0.33 to 0.39 g g-1 when the native XR was replaced by mXR. In contrast, the expression of Gxf1 only slightly increased the xylose uptake, and did not increase the ethanol production. The results suggest that ethanolic xylose fermentation under SSCF conditions is controlled primarily by the XR activity and to a much lesser extent by xylose transport. PMID:21906329

  14. Association of the Maternal MTHFR C677T Polymorphism with Susceptibility to Neural Tube Defects in Offsprings: Evidence from 25 Case-Control Studies

    PubMed Central

    Zou, Peng; Ji, Guixiang; Gu, Aihua; Zhao, Peng

    2012-01-01

    Background Methylenetetrahydrofolate reductase (MTHFR) is a critical enzyme in folate metabolism and is involved in DNA methylation, DNA synthesis, and DNA repair. In addition, it is a possible risk factor in neural tube defects (NTDs). The association of the C677T polymorphism in the MTHFR gene and NTD susceptibility has been widely demonstrated, but the results remain inconclusive. In this study, we performed a meta-analysis with 2429 cases and 3570 controls to investigate the effect of the MTHFR C677T polymorphism on NTDs. Methods An electronic search of PubMed and Embase database for papers on the MTHFR C677T polymorphism and NTD risk was performed. All data were analysed with STATA (version 11). Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association. Sensitivity analysis, test of heterogeneity, cumulative meta-analysis, and assessment of bias were performed in our meta-analysis. Results A significant association between the MTHFR C677T polymorphism and NTD susceptibility was revealed in our meta-analysis ( TT versus CC: OR ?=?2.022, 95% CI: 1.508, 2.712; CT+TT versus CC: OR ?=?1.303, 95% CI: 1.089, 1.558; TT versus CC+CT: OR ?=?1.716, 95% CI: 1.448, 2.033; 2TT+CT versus 2CC+CT: OR ?=?1.330, 95% CI: 1.160, 1.525). Moreover, an increased NTD risk was found after stratification of the MTHFR C677T variant data by ethnicity and source of controls. Conclusion The results suggested the maternal MTHFR C677T polymorphism is a genetic risk factor for NTDs. Further functional studies to investigate folate-related gene polymorphisms, periconceptional multivitamin supplements, complex interactions, and the development of NTDs are warranted. PMID:23056169

  15. Quantitative assessment of the associations between MTHFR C677T and A1298C polymorphisms and risk of fractures: a meta-analysis.

    PubMed

    Bai, Rui; Liu, Wanlin; Zhao, Aiqing; Zhao, Zhenqun; Jiang, Dianming

    2013-03-01

    Many studies have investigated the associations between methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms and risk of fractures, but the impact of MTHFR polymorphisms on fractures risk is unclear owing to the obvious inconsistence among those studies. This study aims to quantify the strength of association between MTHFR C677T and A1298C polymorphisms and risk of fractures. We searched the PubMed, Embase and Wanfang databases for articles relating the association between MTHFR C677T and A1298C polymorphisms and risk of fractures in humans. We estimated summary odds ratios (ORs) with their confidence intervals (CIs) to assess the associations. Meta-analyses suggested MTHFR C677T polymorphism was associated with increased risk of any site fractures (for T vs. C, OR = 1.17, 95 % CI 1.03-1.32; for TT vs. CC, OR = 1. 31, 95 % CI 1.11-1.54; for TT vs. CT, OR = 1.22, 95 % CI 1.04-1.43; for TT vs. CT/CC, OR = 1.31, 95 % CI 1.13-1.51). Besides, MTHFR A1298C polymorphism was also associated with increased risk of any site fractures. Subgroup meta-analyses suggested MTHFR C677T polymorphism was associated with increased risk of vertebral fractures under three genetic contrast modes (for TT vs. CC, OR = 1.43, 95 % CI 1.05-1.95; for TT vs. CT, OR = 1.36, 95 % CI 1.01-1.85; for TT vs. CT/CC, OR = 1.50, 95 % CI 1.17-1.91), but there was no association between MTHFR C677T polymorphism and risk of hip fractures and non-vertebral fractures (all P values were more than 0.05). Thus, individuals with homozygote genotype TT of MTHFR C677T have obviously increased risk of vertebral fractures compared those with heterozygote genotype CT or homozygote genotype CC. There is no association between MTHFR C677T polymorphism and risk of hip fractures and non-vertebral fractures. PMID:23229495

  16. Details in the catalytic mechanism of mammalian thioredoxin reductase 1 revealed using point mutations and juglone-coupled enzyme activities.

    PubMed

    Xu, Jianqiang; Cheng, Qing; Arnér, Elias S J

    2016-05-01

    The mammalian selenoprotein thioredoxin reductase 1 (TrxR1) is a key enzyme in redox regulation, antioxidant defense, and cellular growth. TrxR1 can catalyze efficient reduction of juglone (5-hydroxy-1,4-naphthoquinone; walnut toxin) in a reaction which, in contrast to reduction of most other substrates of TrxR1, is not dependent upon an intact selenocysteine (Sec, U) residue of the enzyme. Using a number of TrxR1 mutant variants, we here found that a sole Cys residue at the C-terminal tail of TrxR1 is required for high-efficiency juglone-coupled NADPH oxidase activity of Sec-deficient enzyme, occurring with mixed one- and two-electron reactions producing superoxide. The activity also utilizes the FAD and the N-terminal redox active disulfide/dithiol motif of TrxR1. If a sole Cys residue at the C-terminal tail of TrxR1, in the absence of Sec, was moved further towards the C-terminal end of the protein compared to its natural position at residue 497, juglone reduction was, surprisingly, further increased. Ala substitutions of Trp407, Asn418 and Asn419 in a previously described "guiding bar", thought to mediate interactions of the C-terminal tail of TrxR1 with the FAD/dithiol site at the N-terminal domain of the other subunit in the dimeric enzyme, lowered turnover with juglone about 4.5-fold. Four residues of Sec-deficient TrxR1 were found to be easily arylated by juglone, including the Cys residue at position 497. Based upon our observations we suggest a model for involvement of the juglone-arylated C-terminal motif of TrxR1 to explain its high activity with juglone. This study thus provides novel insights into the catalytic mechanisms of TrxR1. One-electron juglone reduction by TrxR1 producing superoxide should furthermore contribute to the well-known prooxidant cytotoxicity of juglone. PMID:26898501

  17. The C677T polymorphism of the methylenetetrahydrofolate reductase gene in Mexican mestizo neural-tube defect parents, control mestizo and native populations.

    PubMed

    Dávalos, I P; Olivares, N; Castillo, M T; Cantú, J M; Ibarra, B; Sandoval, L; Morán, M C; Gallegos, M P; Chakraborty, R; Rivas, F

    2000-01-01

    The C677T mutation of the methylenetetrahydrofolate reductase (MTHFR) gene, associated with the thermolabile form of the enzyme, has reportedly been found to be increased in neural-tube defects (NTD), though this association is still unclear. A group of 107 mestizo parents of NTD children and five control populations: 101 mestizo (M), 50 Huichol (H), 38 Tarahumara (T), 21 Purepecha (P) and 20 Caucasian (C) individuals were typed for the MTHFR C677T variant by the PCR/RFLP (HinfI) method. Genotype frequencies were in agreement with the Hardy-Weinberg expectations in all six populations. Allele frequency (%) of the C677T variant was 45 in NTD, 44 in M, 56 in H, 36 in T, 57 in P, 35 in C. Pairwise inter-population comparisons of allele frequency disclosed a very similar distribution between NTD and M groups (exact test, P=0.92). Among controls, differences between M and individual native groups were NS (0.06MTHFR C677T genotypes. Thus, the C677T variant cannot be regarded as a major genetic risk factor for NTD in Mexican mestizo parents. Otherwise, C677T in Mexico is very frequent, especially in Huichol and Purepecha natives, as compared with other groups world wide. PMID:10998450

  18. MTHFR C677T and A1298C polymorphisms and risk of lung cancer: a comprehensive evaluation.

    PubMed

    Yang, Y; Yang, L J; Deng, M Z; Luo, Y Y; Wu, S; Xiong, L; Wang, D; Liu, Y; Liu, H

    2016-01-01

    Results from previous studies on the association between methylenetetrahydrofolate reductase (MTHFR) polymorphisms C677T and A1298C and lung cancer have been conflicting. The aim of this meta-analysis was to clarify the effect of MTHFR polymorphisms on the risk of lung cancer. An electronic search of PubMed, EMBASE, the Cochrane library, and the China Knowledge Resource Integrated Database for papers on C677T and A1298C and susceptibility to lung cancer was performed. The STATA software (Version 13.0) was used for statistical analysis. Statistical heterogeneity, tests of publication bias, and a sensitivity analysis were performed. Twenty-six studies on C677T (12,324 cases and 12,532 controls) and thirteen studies on A1298C (6773 cases and 8207 controls) were included in the meta-analysis. The MTHFR C677T polymorphism showed significant pooled ORs for the homozygote comparison (TT versus CC: OR = 1.518, 95%CI = 1.220-1.890), heterozygote comparison (CT versus CC: OR = 1.053, 95%CI = 0.940-1.179), dominant model (CT + TT versus CC: OR = 1.143, 95%CI = 1.013-1.291), recessive model (TT versus CT + CC: OR = 1.435, 95%CI = 1.190-1.730), and additive model (T versus C: OR = 1.176, 95%CI = 1.066-1.298). In summary, our meta-analysis showed that the MTHFR C677T polymorphism is associated with a significant increase in lung cancer risk in Asian and overall populations, but not in Caucasian populations. However, no significant association between the MTHFR A1298C polymorphism and lung cancer risk was found in either the Caucasian or Asian group with any genetic models. PMID:27173216

  19. Search for correlations between genotypes and electrophysiological patterns in migraine: the MTHFR C677T polymorphism and visual evoked potentials.

    PubMed

    Magis, D; Allena, M; Coppola, G; Di Clemente, L; Gérard, P; Schoenen, J

    2007-10-01

    Interictally, migraineurs have on average a reduction in habituation of pattern-reversal visual evoked potentials (PR-VEP) and in mitochondrial energy reserve. 5,10-Methylenetetrahydrofolate reductase (MTHFR) is involved in folate metabolism and its C677T polymorphism may be more prevalent in migraine. The aim of this study was to search in migraineurs for a correlation between the MTHFR C677T polymorphism and the PR-VEP profile. PR-VEP were recorded in 52 genotyped migraine patients: 40 female, 24 without (MoA), 28 with aura (MA). Among them 21 had a normal genotype (CC), 18 were heterozygous (CT) and 13 homozygous (TT) for the MTHFR C677T polymorphism. Mean PR-VEP N1-P1 amplitude was significantly lower in CT compared with CC, and tended to be lower in TT with increasing age. The habituation deficit was significantly greater in CC compared with TT subjects. The correlation between the cortical preactivation level, as reflected by the VEP amplitude in the first block of averages, and habituation was stronger in CC than in CT or TT. The MTHFR C677T polymorphism could thus have an ambiguous role in migraine. On one hand, the better VEP habituation which is associated with its homozygosity, and possibly mediated by homocysteine derivatives increasing serotoninergic transmission, may protect the brain against overstimulation. On the other hand, MTHFR C677T homozygosity is linked to a reduction of grand average VEP amplitude with illness duration, which has been attributed to brain damage. PMID:17711493

  20. Methylenetetrahydrofolate reductase polymorphisms C677T and risk of autism in the Chinese Han population.

    PubMed

    Guo, Tianyou; Chen, Hong; Liu, Bing; Ji, Weidong; Yang, Chuang

    2012-08-01

    Causes of autism are still unknown. Some studies have shown that autism might be associated with metabolic abnormalities in the folate/homocysteine pathway, which is involved in DNA methylation, thus altering gene expression. The association between the methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphisms and the risk of autism is still controversial and ambiguous. The purpose of this study was to examine the effect of the MTHFR C677T polymorphism on the autism risk in the Chinese Han population. A population-based case-control study was conducted in 186 children with autism and 186 controls. The MTHFR C677T polymorphisms were determined by using a polymerase chain reaction-restriction fragment length polymorphism assay. The frequency of genotype MTHFR 677TT in children with autism (16.1%) was significantly higher (odds ratio [OR]=2.04; 95% confidence interval [CI]=1.07, 3.89; p=0.03] than those in controls (8.6%). When stratifying by select-item scores on the Autism Diagnostic Interview-Revised, it was found that children with current overactivity had a significantly higher frequency of the MTHFR 677TT genotype (OR=2.77, 95% CI=1.17, 6.60; p=0.02) than those without. This study suggested that MTHFR C677T is a risk factor of autism in Chinese Han children. PMID:22775456

  1. Association between methylenetetrahydrofolate reductase C677T polymorphism and psoriasis: A meta-analysis.

    PubMed

    Wu, Dongze; Shi, Deshun; Yang, Li; Zhu, Xiaoliang

    2016-02-01

    Several studies have evaluated the associations between methylenetetrahydrofolate reductase (MTHFR) C677T and psoriasis. However, the results remain inconclusive. The objective of the present study was to conduct a qualitative and quantitative meta-analysis investigating the associations between MTHFR C677T and psoriasis. A published work search of PubMed, Embase, Web of Science and Chinese National Knowledge Infrastructure database were conducted to identify all publications concerning MTHFR C677T polymorphism and psoriasis on 1 October 2014. The principal outcome measure for evaluating the strength of the association was crude odds ratios along with their corresponding 95% confidence intervals. Data were extracted and statistical analyses were implemented using STATA version 12.0 software. A total of 1179 psoriatic cases and 937 controls from five case-control studies concentrating on the association between MTHFR C677T polymorphism and psoriasis were included in this qualitative meta-analysis. Pooled analysis revealed that there is no association between this polymorphism and susceptibility to psoriasis in dominant, recessive, allele and additive models under a random-effect model. However, a marginal significant association was found in the overdominant model under fixed-effect model. Subgroup analysis of ethnicity demonstrated that there is no association between MTHFR C677T polymorphism and either Asian or European psoriatic patients. In conclusion, MTHFR C677T polymorphism, qualitatively, is not a genetic factor for the pathogenesis of psoriasis but could quantitatively reflect the severity of psoriasis to some extent. PMID:26212228

  2. MTHFR C677T Polymorphism is Associated with Tumor Response to Preoperative Chemoradiotherapy: A Result Based on Previous Reports

    PubMed Central

    Zhao, Yue; Li, Xingde; Kong, Xiangjun

    2015-01-01

    Background Preoperative chemoradiotherapy (pRCT) followed by surgery has been widely practiced in locally advanced rectal cancer, esophageal cancer, gastric cancer and other cancers. However, the therapy also exerts some severe adverse effects and some of the patients show poor or no response. It is very important to develop biomarkers (e.g., gene polymorphisms) to identify patients who have a higher likelihood of responding to pRCT. Recently, a series of reports have investigated the association of the genetic polymorphisms in methylenetetrahydrofolate reductase (MTHFR) and epidermal growth factor receptor (EGFR) genes with the tumor response to pRCT; however, the results were inconsistent and inconclusive. Material/Methods A systematic review and meta-analysis was performed by searching relevant studies about the association of MTHFR and EGFR polymorphisms with the tumor regression grade (TRG) in response to pRCT in databases of PubMed, EMBAS, Web of science, Chinese National Knowledge Infrastructure, and Wanfang database up to March 30, 2015. The pooled odds ratios (ORs) with corresponding 95% confidence intervals (95% CIs) were calculated to assess the strength of the association under 5 genetic models. Results A total of 11 eligible articles were included in the present meta-analysis, of which 8 studies were performed in rectal cancer and 3 studies were performed in esophageal cancer. We finally included 8 included studies containing 839 cases for MTHFR C677T, 5 studies involving 634 cases for MTHFR A1298C, 3 studies containing 340 cases for EGFR G497A, and 4 studies containing 396 cases for EGFR CA repeat. The pooled analysis results indicated that MTHFR C677T might be correlated with the tumor response to pRCT under the recessive model (CC vs. CTTT) in overall analysis (OR=1.426(1.074–1.894), P=0.014), rectal cancer (OR=1.483(1.102–1.996), P=0.009), and TRG 1–2 vs. 3–5 group (OR=1.423(1.046–1.936), P=0.025), while other polymorphism including MTHFR A1298C, EGFR G497A, and EGFR CA repeat polymorphisms exerted significant association under all genetic models in overall analysis or subgroup analysis. Conclusions MTHFR C677T might be correlated with the tumor response to pRCT. Further well-designed, larger-scale epidemiological studies are needed to validate our results. PMID:26456456

  3. The Association of Methylenetetrahydrofolate Reductase Genotypes with the Risk of Childhood Leukemia in Taiwan

    PubMed Central

    Chang, Wen-Shin; Ji, Hong-Xue; Hsiao, Chieh-Lun; Miao, Chia-En; Hsu, Yuan-Nian; Bau, Da-Tian

    2015-01-01

    Background Acute lymphoblastic leukemia (ALL) is the most prevalent type of pediatric cancer, the causes of which are likely to involve an interaction between genetic and environmental factors. To evaluate the effects of the genotypic polymorphisms in methylenetetrahydrofolate reductase (MTHFR) on childhood ALL risk in Taiwan, two well-known polymorphic genotypes of MTHFR, C677T (rs1801133) and A1298C (rs1801131), were analyzed to examine the extent of their associations with childhood ALL susceptibility and to discuss the MTHFR genotypic contribution to childhood ALL risk among different populations. Methodology/Principal Findings In total, 266 patients with childhood ALL and an equal number of non-cancer controls recruited were genotyped utilizing PCR-RFLP methodology. The MTHFR C677T genotype, but not the A1298C, was differently distributed between childhood ALL and control groups. The CT and TT of MTHFR C677T genotypes were significantly more frequently found in controls than in childhood ALL patients (odds ratios=0.60 and 0.48, 95% confidence intervals=0.42–0.87 and 0.24–0.97, respectively). As for gender, the boys carrying the MTHFR C677T CT or TT genotype conferred a lower odds ratio of 0.51 (95% confidence interval=0.32–0.81, P=0.0113) for childhood ALL. As for age, those equal to or greater than 3.5 years of age at onset of disease carrying the MTHFR C677T CT or TT genotype were of lower risk (odds ratio= 0.43 and 95% confidence interval=0.26–0.71, P=0.0016). Conclusions Our results indicated that the MTHFR C677T T allele was a protective biomarker for childhood ALL in Taiwan, and the association was more significant in male patients and in patients 3.5 years of age or older at onset of disease. PMID:25793509

  4. Epistasis between COMT and MTHFR in Maternal-Fetal Dyads Increases Risk for Preeclampsia

    PubMed Central

    Hill, Lori D.; York, Timothy P.; Kusanovic, Juan P.; Gomez, Ricardo; Eaves, Lindon J.; Romero, Roberto; Strauss, Jerome F.

    2011-01-01

    Preeclampsia is a leading cause of perinatal morbidity and mortality. This disorder is thought to be multifactorial in origin, with multiple genes, environmental and social factors, contributing to disease. One proposed mechanism is placental hypoxia-driven imbalances in angiogenic and anti-angiogenic factors, causing endothelial cell dysfunction. Catechol-O-methyltransferase (Comt)-deficient pregnant mice have a preeclampsia phenotype that is reversed by exogenous 2-methoxyestradiol (2-ME), an estrogen metabolite generated by COMT. 2-ME inhibits Hypoxia Inducible Factor 1α, a transcription factor mediating hypoxic responses. COMT has been shown to interact with methylenetetrahydrofolate reductase (MTHFR), which modulates the availability of S-adenosylmethionine (SAM), a COMT cofactor. Variations in MTHFR have been associated with preeclampsia. By accounting for allelic variation in both genes, the role of COMT has been clarified. COMT allelic variation is linked to enzyme activity and four single nucleotide polymorphisms (SNPs) (rs6269, rs4633, rs4680, and rs4818) form haplotypes that characterize COMT activity. We tested for association between COMT haplotypes and the MTHFR 677 C→T polymorphism and preeclampsia risk in 1103 Chilean maternal-fetal dyads. The maternal ACCG COMT haplotype was associated with reduced risk for preeclampsia (P = 0.004), and that risk increased linearly from low to high activity haplotypes (P = 0.003). In fetal samples, we found that the fetal ATCA COMT haplotype and the fetal MTHFR minor “T” allele interact to increase preeclampsia risk (p = 0.022). We found a higher than expected number of patients with preeclampsia with both the fetal risk alleles alone (P = 0.052) and the fetal risk alleles in combination with a maternal balancing allele (P<0.001). This non-random distribution was not observed in controls (P = 0.341 and P = 0.219, respectively). Our findings demonstrate a role for both maternal and fetal COMT in preeclampsia and highlight the importance of including allelic variation in MTHFR. PMID:21304959

  5. The impact of C677T and A1298C MTHFR polymorphisms on methotrexate therapeutic response in East Bohemian region rheumatoid arthritis patients.

    PubMed

    Soukup, Tomas; Dosedel, Martin; Pavek, Petr; Nekvindova, Jana; Barvik, Ivan; Bubancova, Iva; Bradna, Petr; Kubena, Ales Antonin; Carazo, Alejandro Fernández; Veleta, Tomas; Vlcek, Jiri

    2015-07-01

    Some single-nucleotide polymorphisms (SNPs) might be predictive of methotrexate (MTX) therapeutic outcome in rheumatoid arthritis (RA). The aim of this study was to determine whether SNPs in the methylenetetrahydrofolate reductase (MTHFR) gene are predictive of MTX response. Comparison was made using EULAR response criteria and according to the change of DAS28 (∆DAS28) after a 6-month MTX treatment in RA patient cohort. The two SNPs C677T (rs1801133) and A1298C (rs1801131) have been genotyped. A total of 120 patients were enrolled in the study, and all of them fulfilled the American College of Rheumatology 1987 RA criteria and are currently or previously taking MTX oral treatment, either as a monotherapy (n = 65) or in a combination with other disease-modifying antirheumatic drugs (n = 55). Genotyping was performed using qPCR allelic discrimination. We did not found any association of C677T and A1298C genotypes with MTX treatment inefficacy in dominant model (OR 1.23, 95 % CI 0.57-2.65, P = 0.697; and OR 0.98, 95 % CI 0.47-2.14, P = 1.0, respectively), or in recessive and codominant models. However, when ∆DAS28 after a 6-month therapy was used as a measure of treatment efficacy, the 677CT and 1298AC genotypes were found to be significantly associated with less favorable response to MTX (P = 0.025 and P = 0.043, respectively). In addition, even lower ∆DAS28 was determined for double-mutated 677CT-1298AC heterozygotes. It means that a synergistic effect of 677CT and 1298AC genotypes was observed. Nevertheless, the DAS28 baseline was lower here comparing to other genotypes. Unexpectedly, quite the opposite trend-i.e., better response to MTX-was found in genotypes 677CC-1298CC and 677TT-1298AA. It is an intriguing finding, because these double-mutated homozygotes are known for their low MTHFR-specific activity. Global significance was P = 0.013, η (2) = 0.160-i.e., large-size effect. Thus, our data show greater ability of 677CC-1298CC and 677TT-1298AA genotypes to respond to MTX treatment. PMID:25618758

  6. A case of vascular parkinsonism associated with hyperhomocysteinemia and methylenetetrahydrofolate reductase gene variant (C677T).

    PubMed

    Hara, Kenju; Onda, Keigo; Ouchi, Haruka; Shibano, Ken; Ishiguro, Hideaki

    2016-03-01

    A 56-year-old man, who presented with 6 years history of difficulty in walking, was diagnosed as having vascular parkinsonism on the basis of the clinical findings of parkinsonism, pyramidal sign and the brain MRI findings of multiple lacunar infarction. Although he did not have hypertension, he had hyperhomocysteinemia and homozygous methylenetetrahydrofolate reductase (MTHFR) gene variant (C677T) as risk factors for ischemic stroke. Recent studies have shown that hyperhomocysteinemia and MTHFR gene variant are associated with small-vessel disease, suggesting that these risk factors may underlie vascular parkinsonism, particularly in patients lacking hypertension and in those with a relatively younger age at onset of this disease. PMID:26797478

  7. Polymorphisms of glutathione S-transferase and methylenetetrahydrofolate reductase genes in Moldavian patients with ulcerative colitis: Genotype-phenotype correlation

    PubMed Central

    Varzari, Alexander; Deyneko, Igor V.; Tudor, Elena; Turcan, Svetlana

    2015-01-01

    Background Glutathione S-transferases (GSTM1, GSTT1, and GSTP1) and methylenetetrahydrofolate reductase (MTHFR) are important enzymes for protection against oxidative stress. In addition, MTHFR has an essential role in DNA synthesis, repair, and methylation. Their polymorphisms have been implicated in the pathogenesis of ulcerative colitis (UC). The aim of the present study was to investigate the role of selected polymorphisms in these genes in the development of UC in the Moldavian population. Methods In a case-control study including 128 UC patients and 136 healthy individuals, GSTM1 and GSTT1 genotypes (polymorphic deletions) were determined using multiplex polymerase chain reaction (PCR). The GSTP1 rs1695 (Ile105Val), MTHFR rs1801133 (C677T), and MTHFR rs1801131 (A1298C) polymorphisms were studied with restriction fragment length polymorphism (RFLP) analysis. Genotype–phenotype correlations were examined using logistic regression analysis. Results None of the genotypes, either alone or in combination, showed a strong association with UC. The case-only sub-phenotypic association analysis showed an association of the MTHFR rs1801133 polymorphism with the extent of UC under co-dominant (p corrected = 0.040) and recessive (p corrected = 0.020; OR = 0.15; CI = 0.04–0.63) genetic models. Also, an association between the MTHFR rs1801131 polymorphism and the severity of UC was reported for the over-dominant model (p corrected = 0.023; coefficient = 0.32; 95% CI = 0.10–0.54). Conclusion The GST and MTHFR genotypes do not seem to be a relevant risk factor for UC in our sample. There was, however, evidence that variants in MTHFR may influence the clinical features in UC patients. Additional larger studies investigating the relationship between GST and MTHFR polymorphisms and UC are required. PMID:26862484

  8. Alteration of the alkaloid profile in genetically modified tobacco reveals a role of methylenetetrahydrofolate reductase in nicotine N-demethylation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme of the tetrahydrofolate (THF)-mediated one-carbon (C1) metabolic network. This enzyme catalyzes reduction of 5,10-methylene-THF to 5-methyl-THF. The latter donates its methyl group to homocysteine forming Met, which is then used for the syn...

  9. Sodium arsenite alters cell cycle and MTHFR, MT1/2, and c-Myc protein levels in MCF-7 cells

    SciTech Connect

    Ruiz-Ramos, Ruben; Lopez-Carrillo, Lizbeth; Albores, Arnulfo; Hernandez-Ramirez, Raul U.; Cebrian, Mariano E.

    2009-12-15

    There is limited available information on the effects of arsenic on enzymes participating in the folate cycle. Therefore, our aim was to evaluate the effects of sodium arsenite on the protein levels of methylenetetrahydrofolate reductase (MTHFR) and dihydrofolate reductase (DHFR) and its further relationship with the expression MT1/2 and c-myc in MCF-7 cells. Arsenite treatment (0-10 muM) for 4 h decreased MTHFR levels in a concentration-dependent fashion without significant effects on DHFR. The effects on MTHFR were observed at arsenite concentrations not significantly affecting cell viability. We also observed an increase in S-phase recruitment at all concentrations probed. Lower concentrations (< 5 muM) induced cell proliferation, showing a high proportion of BrdU-stained cells, indicating a higher DNA synthesis rate. However, higher concentrations (>= 5 muM) or longer treatment periods induced apoptosis. Arsenite also induced dose-dependent increases in MT1/2 and c-Myc protein levels. The levels of MTHFR were inversely correlated to MT1/2 and c-Myc overexpression and increased S-phase recruitment. Our findings indicate that breast epithelial cells are responsive to arsenite and suggest that exposure may pose a risk for breast cancer. The reductions in MTHFR protein levels contribute to understand the mechanisms underlying the induction of genes influencing growth regulation, such as c-myc and MT1/2. However, further research is needed to ascertain if the effects here reported following short-time and high-dose exposure are relevant for human populations chronically exposed to low arsenic concentrations.

  10. Maternal polymorphisms 677C-T and 1298A-C of MTHFR, and 66A-G MTRR genes: is there any relationship between polymorphisms of the folate pathway, maternal homocysteine levels, and the risk for having a child with Down syndrome?

    PubMed

    Martínez-Frías, María-Luisa; Pérez, Belén; Desviat, Lourdes R; Castro, Margarita; Leal, Fátima; Rodríguez, Laura; Mansilla, Elena; Martínez-Fernández, María-Luisa; Bermejo, Eva; Rodríguez-Pinilla, Elvira; Prieto, David; Ugarte, Magdalena

    2006-05-01

    This study was aimed at analyzing the effect of mutations in three non-synonymous SNP genes (677C > T and 1298A > C of the methylenetetrahydrofolate reductase (MTHFR) gene, and 66A > G in the MTRR gene) on total plasmatic homocysteine (Hcy), in 91 mothers of Down syndrome (DS) infants and 90 control mothers. The comparison of both groups of mothers is a new way to determine if those mutations and their interactions increase the risk for DS. Material came from the case-control network of the Spanish Collaborative Study of Congenital Malformations (ECEMC). Using a general lineal model in a backwards step, we performed the analyses including the different mutations, maternal age, the fact that each mother had a DS or a control infant, and all possible interactions of these variables, in the models, being maternal Hcy the continuous dependent variable. In another model, maternal folic acid intake during the third trimester of pregnancy was added. The results from both models were essentially the same: Hcy levels variability differs from case mothers to control ones, the presence of the MTHFR1298A > C polymorphism also affects significantly the Hcy variance, as it does the statistical interaction between the mutations MTRR66A > G and MTHFR1298A > C in the mother. In this sense, the interaction between different polymorphisms may totally modify their individual effects, and some of those effects are different in mothers of DS children and in controls' mothers. For instance, only two mutations in MTRR66 (GGAA) in mothers of control infants increase the reference maternal Hcy level in 4.66 units, and the individual effect of the genotype with only two mutations in the MTHFR1298 gene (AACC) increases the reference Hcy level in 12.74 units. However, the presence of the four mutations (GGCC) interacts giving a statistically significant decrease in 6.00 units in the level of Hcy in control mothers. On the contrary, in mothers of DS infants, the sole presence of two mutations in one of these two genes decreases the levels of Hcy (-2.31 units for GGAA genotype, and -3.43 units for AACC genotype), while the presence of the four mutations (GGCC) increases Hcy in 9.53 units. Taking into consideration that in the one-carbon metabolism cystathionine beta-synthase (CBS) catalyzes Hcy in an irreversible way, and that CBS gene is located in chromosome 21, fetuses and infants with DS have functional folate deficiency due to overexpression of CBS. This fact, as well as others influencing Hcy levels (such as nutrients interactions and lifestyle), together with the fetal genotype, suggest that their relationship with DS could be through an effect on fetal survival up to birth. Three possible mechanisms are considered by evaluating the results in the light of the present knowledge on cytology and molecular biology. PMID:16575899

  11. Pulmonary Embolism in a Sarcoidosis Patient Double Heterozygous for Methylenetetrahydrofolate Reductase Gene Polymorphisms and Factor V Leiden and Homozygous for the D-Allele of Angiotensin Converting Enzyme Gene

    PubMed Central

    El-Majzoub, Nadim; Mahfouz, Rami; Kanj, Nadim

    2015-01-01

    Sarcoidosis is a multisystem granulomatous disease of unknown etiology and pathogenesis. It presents in patients younger than 40 years of age. The lungs are the most commonly affected organ. Till the present day, there is no single specific test that will accurately diagnose sarcoidosis; as a result, the diagnosis of sarcoidosis relies on a combination of clinical, radiologic, and histologic findings. Patients with sarcoidosis have been found to have an increased risk of pulmonary embolism compared to the normal population. MTHFR and factor V Leiden mutations have been reported to increase the risk of thrombosis in patients. We hereby present a case of a middle aged man with sarcoidosis who developed a right main pulmonary embolism and was found to be double heterozygous for methylenetetrahydrofolate reductase gene polymorphisms and factor V Leiden and homozygous for the D-allele of the angiotensin converting enzyme gene. PMID:26347783

  12. MTHFR C677T and A1298C variant genotypes and the risk of microsatellite instability among Iranian colorectal cancer patients.

    PubMed

    Naghibalhossaini, Fakhraddin; Mokarram, Pooneh; Khalili, Islam; Vasei, Mohammad; Hosseini, Seyed Vahid; Ashktorab, Hassan; Rasti, Mozhgan; Abdollahi, Kourosh

    2010-03-01

    Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in the folate metabolic pathway. We aimed to test the hypothesis that C677T and A1298C variants of MTHFR predispose to microsatellite instable (MSI) colorectal cancer. We determined MTHFR genotypes in 175 sporadic colorectal cancer patients and a total of 231 normal controls in Shiraz, Southern Iran. Among the genotypes found in our samples, MTHFR CT and CT+TT were associated with increased risk for CRC incidence [odds ratio (OR)=2.4, 95% confidence interval (95%CI)=1.8-4.4; OR=2.4, 95%CI=1.6-3.6, respectively]. Double heterozygotes 677CT/1298AC and double homozygote 677TT/1298AA and 677CC/1298CC genotypes also showed a significantly increased risk of developing CRC compared with the wild-type 677CC/1298AA genotypes of the controls. Among the 151 tumors tested, 36 (23.8%) were MSI+. MSI was more common in proximal tumors (OR=10.4; 95%CI=3.9-27.8) and in smokers (OR=2.9; 95%CI=1.3-6.7). In a case-control comparison, the MTHFR 677CT+TT genotype was strongly associated with MSI (OR=2.6; 95%CI=1.3-5.3). Hypermethylation of mismatch repair genes was positively related with MSI incidence in these tumor series (P=0.00). Our data suggest that the MTHFR 677CT+TT variant genotype may be a risk factor for MSI+ cancer. PMID:20193847

  13. Glutamatergic synapse protein composition of wild-type mice is sensitive to in utero MTHFR genotype and the timing of neonatal vigabatrin exposure.

    PubMed

    Zuckerman, Chava; Blumkin, Elinor; Melamed, Osnat; Golan, Hava M

    2015-10-01

    The enzyme methylenetetrahydrofolate-reductase (MTHFR) is part of the homocysteine and folate metabolic pathways. In utero, Mthfr-deficient environment has been reported as a risk factor for neurodevelopmental disorders such as autism and neural tube defects. Neonatal disruption of the GABAergic system is also associated with behavioral outcomes. The interaction between Mthfr deficiency and neonatal exposure to the GABA-potentiating drug vigabatrin (GVG) in mice alters anxiety, memory, and social behavior in a gender-dependent manner. In addition, a gender-dependent enhancement of proteins implicated in excitatory synapse plasticity in the cerebral cortex was shown. Here we show that in utero MTHFR deficiency is sufficient to alter the levels of glutamate receptor subunits GluR1, GluR2, and NR2B in the cerebral cortex and hippocampus of adult offspring with a WT genotype. In addition, FMRP1, CAMKII α and γ, and NLG1 levels in WT offspring were vulnerable to the in utero genotype. These effects depend on brain region and the cellular compartment tested. The effect of in utero MTHFR deficiency varies with the age of neonatal GVG exposure to modify GluR1, NR2A, reelin, CAMKII α, and NLG1 levels. These changes in molecular composition of the glutamatergic synapse were associated with increased anxiety-like behavior. Complex, multifactorial disorders of the nervous system show significant association with several genetic and environmental factors. Our data exemplify the contribution of an in utero MTHFR-deficient environment and early exposure to an antiepileptic drug to the basal composition of the glutamatergic synapses. The robust effect is expected to alter synapse function and plasticity and the cortico-hippocampal circuitry. PMID:26235956

  14. MTHFR gene A1298C polymorphisms are associated with breast cancer risk among Chinese population: evidence based on an updated cumulative meta-analysis

    PubMed Central

    Wang, Yadong; Yang, Haiyan; Duan, Guangcai

    2015-01-01

    Objectives: Published studies on the association between methylenetetrahydrofolate reductase (MTHFR) gene A1298C polymorphisms and breast cancer risk among Chinese population have yielded conflicting results. The purpose of this study was to clarify the association between MTHFR gene A1298C polymorphisms and breast cancer risk among Chinese population. Methods: Systematic searches were performed through the database of Medline/PubMed, Science Direct, Elsevier, CNKI and Wanfang Medical Online. Results: Overall, a significantly increased risk of breast cancer was observed among the subjects carrying MTHFR gene A1298C AC+CC genotype (odds ratio [OR]=1.05 with 95% confidence interval [CI]: 1.01-1.10) as compared to those carrying AA genotype among total Chinese population. We did not observe any significant association between MTHFR gene A1298C polymorphisms and the risk of breast cancer under the additional genetic models of AC vs. AA, CC vs. AA and C-allele vs. A-allele (OR=1.00 with 95% CI: 0.97-1.02, OR=1.01 with 95% CI: 1.00-1.02 and OR=1.00 with 95% CI: 0.99-1.02, respectively). The cumulative meta-analysis showed similar results. In subgroup analysis, we observed subjects carrying AC+CC genotype had an increased breast cancer risk compared with those carrying AA genotype among the studies of sample size less than 1000. We did not observe any significant association between MTHFR gene A1298C polymorphisms and breast cancer risk in additional subgroup analyses. Conclusions: Our results suggest that MTHFR gene A1298C AC+CC genotype may be a risk factor for the development of breast cancer among Chinese population. Well-designed studies with a large sample size are needed to further confirm our findings. PMID:26884927

  15. Polymorphisms in NOS3, MTHFR, APOB and TNF-α Genes and Risk of Coronary Atherosclerotic Lesions in Iranian Patients

    PubMed Central

    Heidari, Mohammad Mehdi; Khatami, Mehri; Hadadzadeh, Mehdi; Kazemi, Mahbobeh; Mahamed, Sahar; Malekzadeh, Pegah; Mirjalili, Massomeh

    2015-01-01

    Background: Atherosclerosis is a complex multifocal arterial disease involving interactions between multiple genetic and environmental factors. Objectives: In the present study, we investigated the possible association between NOS3 (rs1799983), MTHFR (rs1801133), APOB (rs5742904) and TNF-α (rs361525) polymorphisms and the risk of coronary atherosclerotic lesions in Iranian patients. Patients and Methods: In the case-control study, 108 patients with coronary atherosclerosis disease and 95 control subjects with no family history of cardiovascular disease were enrolled. Genotypes for NOS3, MTHFR, APOB and TNF-α polymorphisms were identified using polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP). Results: We specifically detected the NOS3 TT genotype in 12 patients (11.11%) and did not find the same genotype in any of the controls. The frequencies of T allele in patients and the controls were 24% and 17.8%, respectively. The prevalence of the MTHFR TT genotype was 16.7% in patients and 2.2% in control groups. The prevalence of the APOB-100 (R3500Q) mutation in this patient population was 0%. The frequency of the A allele in the TNF-α gene was 11.1% and 11% in patients and controls, respectively, and the AA genotype was undetected. Conclusions: Our results show a significant association of NOS3 and MTHFR gene polymorphisms with coronary atherosclerotic lesions. Therefore, these variants might influence the risk of coronary artery disease, specifically in the Iranian population. PMID:26878010

  16. Role of MTHFR C677T and MTR A2756G polymorphisms in thyroid and breast cancer development.

    PubMed

    Zara-Lopes, T; Gimenez-Martins, A P A; Nascimento-Filho, C H V; Castanhole-Nunes, M M U; Galbiatti-Dias, A L S; Padovani-Júnior, J A; Maniglia, J V; Francisco, J L E; Pavarino, E C; Goloni-Bertollo, E M

    2016-01-01

    Folate metabolism is essential for DNA synthesis and repair. Alterations in genes that participate in folate metabolism can be associated with several types of malignant neoplasms, including thyroid and breast cancer. In the present case-control study, we examined the association between methylenetetrahydrofolate reductase (MTHFR C677T, rs1801133) and methionine synthase (MTR A2756G, rs1805087) polymorphisms and risk for thyroid and breast cancer. Polymerase chain reaction-restriction fragment length technique was used to determine the specific genotypes in the genes of interest. Statistical analysis was performed by multiple logistic regression test. We found an association between MTHFR C677T polymorphism and risks to both thyroid (OR = 2.50; 95%CI = 1.15-5.46; P = 0.02) and breast cancer (OR = 2.53; 95%CI = 1.08-5.93; P = 0.03). Tobacco consumption and high body mass index were also associated with thyroid cancer. In addition, increased age (≥50 years) and alcohol consumption were found to be associated with breast cancer. Our results indicated that MTHFR C677T is significantly associated with thyroid and breast cancer risks. Thus, these factors may be used as potential prognostic markers for thyroid and breast cancers. PMID:27173331

  17. MTHFR C677T polymorphism contributes to prostate cancer risk among Caucasians: A meta-analysis of 3511 cases and 2762 controls.

    PubMed

    Bai, Jian-Ling; Zheng, Ming-Hua; Xia, Xian; Ter-Minassian, Monica; Chen, Yong-Ping; Chen, Feng

    2009-05-01

    Published data regarding the association between 5,10-methylenetetrahydrofolate reductase (MTHFR) polymorphisms and prostate cancer risk have been conflicting. To derive a more precise estimation of the relationship, a meta-analysis was performed. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association between MTHFR C677T and A1298C polymorphisms and prostate cancer risk. Six studies including 3511 cases and 2762 controls described C677T genotypes, among which four articles totalling 838 cases and 1121 controls described A1298C genotypes, were involved in this meta-analysis. Overall meta-analysis indicated that the 677T allele was more likely to exert a protective effect on prostate cancer risk (OR=0.81, 95% CI: 0.68-0.98) with a recessive genetic model. No association was found for the 677CT genotype and the 677TT mutant homozygote with prostate cancer risk compared with 677CC, with OR=1.13 (95% CI: 0.88-1.45) and OR=0.85 (95% CI: 0.71-1.03), respectively. No evidence of an association of MTHFR A1298C polymorphism with prostate cancer was found. This meta-analysis supports that the C677T of the MTHFR gene is a low-penetrance susceptibility gene for prostate cancer, and might provide protective effects against prostate cancer risk. PMID:19223177

  18. Association between MTHFR C677T Polymorphism and Risk of Acute Lymphoblastic Leukemia: A Meta-Analysis Based on 51 Case-Control Studies

    PubMed Central

    Li, Su-yi; Ye, Jie-yu; Liang, En-yu; Zhou, Li-xia; Yang, Mo

    2015-01-01

    Background Studies and systematic reviews have reached inconsistent conclusions on the role of 5, 10-methylenetetrahydrofolate reductase (MTHFR) polymorphism C677T in acute lymphoblastic leukemia (ALL) risk. Material/Methods The present meta-analysis comprising of 51 case-control studies, including 7892 cases and 14 280 controls was performed to reevaluate the association between MTHFR C677T polymorphism and ALL risk. Results Statistical differences were found in the dominant model (TT+CT vs. CC, odd ratio (OR)=0.89, 95% CI, 0.79–1.00, P=0.04) and the CT vs. CC (OR=0.89, 95% CI, 0.80–1.00, P=0.05), but not in the allele contrast model (T vs. C, OR=0.92, 95% CI, 0.84–1.01, P=0.08), additive model (TT vs. CC, OR=0.87, 95% CI, 0.73–1.05, P=0.15), or recessive model (TT vs. CT+CC, OR=0.94, 95% CI, 0.81–1.10, P=0.44) in overall populations. In the subgroup analyses stratified by age (children and adults) and ethnicity (Asian and Caucasian), no significant associations between MTHFR C677T polymorphism and ALL risk were observed. Conclusions The current study found no sufficient evidence of a protective role of MTHFR C677T polymorphism in ALL susceptibility. PMID:25761797

  19. Association Between MTHFR Polymorphisms and Congenital Heart Disease: A Meta-analysis based on 9,329 cases and 15,076 controls

    PubMed Central

    Xuan, Chao; Li, Hui; Zhao, Jin-Xia; Wang, Hong-Wei; Wang, Yi; Ning, Chun-Ping; Liu, Zhen; Zhang, Bei-Bei; He, Guo-Wei; Lun, Li-Min

    2014-01-01

    The aim of our study was to evaluate the association between polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene and the risk for congenital heart disease (CHD). Electronic literature databases were searched to identify eligible studies published before Jun, 2014. The association was assessed by the odds ratio (OR) with a 95% confidence interval (CI). The publication bias was explored using Begg's test. Sensitivity analysis was performed to evaluate the stability of the crude results. A total of 35 studies were included in this meta-analysis. For the MTHFR C677T polymorphism, we detected significant association in all genetic models for Asian children and the maternal population. Significant association was also detected in T vs. C for a Caucasian paediatric population (OR = 1.163, 95% CI: 1.008–1.342) and in both T vs. C (OR = 1.125, 95% CI: 1.043–1.214) and the dominant model (OR = 1.216, 95% CI:b1.096–1.348) for a Caucasian maternal population. For the MTHFR A1298C polymorphism, the association was detected in CC vs. AC for the Caucasian paediatric population (OR = 1.484, 95% CI: 1.035–2.128). Our results support the MTHFR -677T allele as a susceptibility factor for CHD in the Asian maternal population and the -1298C allele as a risk factor in the Caucasian paediatric population. PMID:25472587

  20. Bladder exstrophy-epispadias complex and the role of methylenetetrahydrofolate reductase C677T polymorphism: A case control study

    PubMed Central

    Raman, Venkat Shankar; Bajpai, Minu; Ali, Abid

    2016-01-01

    Purpose: The Bladder Exstrophy-Epispadias Complex (BEEC) is the most serious form of midline abdominal malformation. The etiology of BEEC is unknown and is thought to be multifactorial. Methylenetetrahydrofolate reductase (MTHFR) polymorphism C677T is strongly associated with other midline abnormalities such as neural tube defects. No proper case-control study existed comparing MTHFR polymorphism with BEEC. We sought to find an association with MTHFR polymorphism and patients with bladder exstrophy (BE). Materials and Methods: The design of the study was a case-control study, involving 50 children with BEEC and 50 normal healthy school children. Genetic analysis for MTHFR 677 polymorphism was carried out after DNA extraction and polymerase chain reaction amplification. Epidemiological analysis was done by using the birth defect questionnaire on parents of BEEC. Results: Forty-two classical BE, two cloacal exstrophies (CE), four epispadias, and two exstrophy variant patients were a part of this study. Severe variety of BE had a significant association with C667T MTHFR polymorphism as compared to the normal control population (P = 0.01). Conclusion: C677T MTHFR polymorphism has a strong association with severe variety (CE) of BEEC occurrence. PMID:26862292

  1. MTHFR A1298C and C677T gene polymorphisms and susceptibility to chronic myeloid leukemia in Egypt.

    PubMed

    Aly, Rabab M; Taalab, Mona M; Ghazy, Hayam F

    2014-01-01

    Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme regulating the intracellular folate metabolism which plays an important role in carcinogenesis through DNA methylation. We aimed to evaluate the association between MTHFR A1298C and C677T polymorphisms and the risks of chronic myeloid leukemia (CML). Eighty-five patients with CML and a control group containing 100 healthy, age and sex matched individuals were examined for MTHFR C677T and A1298C polymorphisms using polymerase chain reaction-restriction fragment-length (PCR-RFLP) method. The frequency of 677TT genotype in patients with CML was significantly higher compared to controls (OR=2.513, 95% CI: 0.722-4.086, P=0.025). No such association was shown for heterozygous 677CT (OR=1.010, 95% CI: 0.460-2.218, P=0.981). Moreover, for A1298C genotype, a statistically significant higher frequency of 1298CC was also detected in CML patients compared to control group (OR=1.1816, 95% CI: 0.952-3.573, P=0.036), 0.036). No such statistical significance was demonstrable for heterozygote 1298AC (OR=1.046, 95% CI: 0.740-1.759, P=0.092). In addition, patients with joint 677CT/1298AC or 677TT/1298CC genotypes showed an association with increased risk of CML (OR=1.849, 95% CI: 0.935-2.540, P=0.024; OR=1.915, 95% CI: 1.202-3.845, P=0.020 respectively). .A statistically significant increased risk of resistant to therapy was observed with 677CT and 1298AC genotypes (P=0.001, P=0.002 respectively). We conclude that both MTHFR 677TT and 1298CC polymorphisms have been associated with risk of CML and both 677CT and 1298AC genotypes are associated with higher risk of resistant to therapy. PMID:24966971

  2. Folate intake and the MTHFR C677T genotype influence choline status in young Mexican American women☆

    PubMed Central

    Abratte, Christian M.; Wang, Wei; Li, Rui; Moriarty, David J.; Caudill, Marie A.

    2009-01-01

    Numerous studies have reported a relationship between folate status, the methylenetetrahydrofolate reductase (MTHFR) 677C→T variant and disease risk. Although folate and choline metabolism are inter-related, only limited data are available on the relationship between choline and folate status in humans. This study sought to examine the influences of folate intake and the MTHFR 677C→T variant on choline status. Mexican-American women (n =43; 14 CC, 12 CT and 17 TT) consumed 135 μg/day as dietary folate equivalents (DFE) for 7 weeks followed by randomization to 400 or 800 μg DFE/day for 7 weeks. Throughout the study, total choline intake remained unchanged at ∼350 mg/day. Plasma concentrations of betaine, choline, glycerophosphocholine, phosphatidylcholine and sphingomyelin were measured via LC-MS/MS for Weeks 0, 7 and 14. Phosphatidylcholine and sphingomyelin declined ( P=.001, P=.009, respectively) in response to folate restriction and increased ( P=.08, P=.029, respectively) in response to folate treatment. The increase in phosphatidylcholine occurred in response to 800 ( P=.03) not 400 ( P=.85) μg DFE/day (week×folate interaction, P=.017). The response of phosphatidylcholine to folate intake appeared to be influenced by MTHFR C677T genotype. The decline in phosphatidylcholine during folate restriction occurred primarily in women with the CC or CT genotype and not in the TT genotype (week×genotype interaction, P=.089). Moreover, when examined independent of folate status, phosphatidylcholine was higher ( P <.05) in the TT genotype relative to the CT genotype. These data suggest that folate intake and the MTHFR C677T genotype influence choline status in humans. PMID:17588738

  3. The methylenetetrahydrofolate reductase C677T polymorphism influences risk of esophageal cancer in Chinese.

    PubMed

    Qu, Hong-Hong; Cui, Li-Hong; Wang, Ke; Wang, Peng; Song, Chun-Hua; Wang, Kai-Juan; Zhang, Jian-Ying; Dai, Li-Ping

    2013-01-01

    Methylenetetrahydrofolate reductase (MTHFR) plays a central role in folate metabolism. This study with 381 esophageal cancer patients and 432 healthy controls was conducted to examine the association of MTHFR C677T and A1298C polymorphisms with susceptibility to esophageal cancer (EC) in a Chinese population. Compared with the CC genotype of MTHFR C677T, subjects carrying homozygote TT and variant genotypes (CT+TT) demonstrated reduced risk of EC with adjusted ORs (95% CI) of 0.44 (0.28-0.71) and 0.57 (0.37-0.88), respectively. However, no association was found between the MTHFR A1298C polymorphism and the risk of EC. Comparing to haplotype CA, haplotypes TA and TC could reduce the susceptibility to EC with adjusted ORs (95% CI) of 0.61(0.47-0.79) and 0.06 (0.01-0.43), respectively. In conclusion, the present study suggested that the MTHFR C677T polymorphism can markedly influence the risk of EC in Chinese. PMID:23803097

  4. Severe methylenetetrahydrofolate reductase deficiency in mice results in behavioral anomalies with morphological and biochemical changes in hippocampus.

    PubMed

    Jadavji, Nafisa M; Deng, Liyuan; Leclerc, Daniel; Malysheva, Olga; Bedell, Barry J; Caudill, Marie A; Rozen, Rima

    2012-06-01

    The brain is particularly sensitive to folate metabolic disturbances, since methyl groups are critical for its functions. Methylenetetrahydrofolate reductase (MTHFR) generates the primary circulatory form of folate required for homocysteine remethylation to methionine. Neurological disturbances have been described in homocystinuria caused by severe MTHFR deficiency. The goal of this study was to determine if behavioral anomalies are present in severe Mthfr-deficient (Mthfr(-/-)) mice and to identify neurobiological changes that could contribute to these anomalies. Adult male mice of 3 Mthfr genotypes (+/+, +/-, -/-) were tested on motor, anxiety, exploratory and cognitive tasks. Volumes (whole brain and hippocampus) and morphology, global DNA methylation, apoptosis, expression of choline acetyltransferase (ChAT) and glucocorticoid receptor (GR), and concentrations of choline metabolites were assessed in hippocampus. Mthfr(-/-) mice had impairments in motor function and in short- and long-term memory, increased exploratory behavior and decreased anxiety. They showed decreased whole brain and hippocampal volumes, reduced thickness of the pyramidal cell layer of CA1 and CA3, and increased apoptosis in hippocampus. There was a disturbance in choline metabolism as manifested by differences in acetylcholine, betaine or glycerophosphocholine concentrations, and by increased ChAT levels. Mthfr(-/-) mice also had increased GR mRNA and protein. Our study has revealed significant anomalies in affective behavior and impairments in memory of Mthfr(-/-) mice. We identified structural changes, increased apoptosis, altered choline metabolism and GR dysregulation in hippocampus. These findings, as well as some similar observations in cerebellum, could contribute to the behavioral changes and suggest that choline is a critical metabolite in homocystinuria. PMID:22521626

  5. Relationship between MTHFR C677T and A1298C gene polymorphisms and complications of type 2 diabetes mellitus in an Emirati population

    PubMed Central

    El Hajj Chehadeh, Sarah W.; Jelinek, Herbert F.; Al Mahmeed, Wael A.; Tay, Guan K.; Odama, Unini O.; Elghazali, Gehad E.B.; Al Safar, Habiba S.

    2016-01-01

    Purpose Type 2 diabetes mellitus (T2DM) is the most common form of diabetes with clinical consequences giving rise to chronic multiple organ complications. Methylenetetrahydrofolate reductase (MTHFR) polymorphisms are genetic variations that have been linked to T2DM, and micro/macrovascular complications. The link between MTHFR and T2DM however is strongly dependent on the ethnic group studied. The objective of this study was to investigate the possible association between two MTHFR polymorphisms (C677T and A1298C) and T2DM and specifically examine if there are any associations with clinical and demographic characteristics among patients in the United Arab Emirates (UAE). Methods The study included 169 T2DM patients and 209 healthy controls. Genomic DNA was isolated and genotyped using TaqMan real-Time PCR assays for the MTHFR C677T and A1298C polymorphisms. Results There were no significant differences in genotype and haplotype distributions observed between groups. A significant association was observed between the C677T polymorphism and history of cerebrovascular accident (CVA) (p = 0.0330), history of nephropathy (p = 0.0280) and levels of LDL cholesterol (p = 0.0409). Also, the A1298C polymorphism was associated with hypertriglyceridemia (p = 0.0305) in T2DM patients. Conclusion These findings demonstrate that the MTHFR gene polymorphisms are not related to T2DM in the Emirati population. However, these polymorphisms can be used as risk markers for CVA, nephropathy, high LDL cholesterol and triglycerides in T2DM patients and allow timely treatment.

  6. Association between MTHFR gene polymorphisms (C677T, A1298C) and genetic susceptibility to prostate cancer: a meta-analysis.

    PubMed

    Chen, P L; Li, W T; Wang, J; Jiang, Y D; Wu, P; Chen, T; Zheng, S B

    2015-01-01

    Genetic polymorphisms (C677T and A1298C) in methylenetetrahydrofolate reductase (MTHFR) were shown to be related to prostate cancer risk in previous studies; however, the results are controversial. We performed a meta-analysis of previous studies and quantitatively estimated these associations. Pubmed, Embase, and Cochrane Library Database were searched for published case-control studies evaluating the association between C677T (or A1298C) and prostate cancer risk. Pooled associations were presented as odds ratios (ORs) along with their 95% confidence intervals. Twenty-one case control studies were identified for meta-analysis that included 21,581 participants. No significant associations were found between the MTHFR polymorphisms C677T or A1298C and prostate cancer risk in our meta-analysis. However, in subgroup analyses, the C677T CT polymorphism was associated with increased prostate cancer risk in East Asians (CT vs CC+TT: OR = 1.324, P = 0.03). The A1298C CC polymorphism in MTHFR was also linked to slightly reduced prostate cancer risk in European residents (CC vs AC+AA: OR = 0.751, P = 0.004; CC vs AA: OR = 0.768, P = 0.011), whereas it was associated with a significantly increased prostate cancer risk in Asian residents (CC vs AA: OR = 1.862, P = 0.006). The C677T CT polymorphism of MTHFR may be a risk factor for prostate cancer in East Asians. The association between the MTHFR A1298C CC genotype and prostate cancer risk may vary within different populations. Large-scale well-designed studies are required to confirm these associations. PMID:26782572

  7. MTHFR C677T genotype influences the isotopic enrichment of one-carbon metabolites in folate-compromised men consuming d9-choline123

    PubMed Central

    Yan, Jian; Wang, Wei; Gregory, Jesse F; Malysheva, Olga; Brenna, J Thomas; Stabler, Sally P; Allen, Robert H; Caudill, Marie A

    2011-01-01

    Background: Homozygosity for the variant 677T allele in the methylenetetrahydrofolate reductase (MTHFR) gene increases the requirement for folate and may alter the metabolic use of choline. The choline adequate intake is 550 mg/d for men, although the metabolic consequences of consuming extra choline are unclear. Objective: Deuterium-labeled choline (d9-choline) as tracer was used to determine the differential effects of the MTHFR C677T genotype and the effect of various choline intakes on the isotopic enrichment of choline derivatives in folate-compromised men. Design: Mexican American men with the MTHFR 677CC or 677TT genotype consumed a diet providing 300 mg choline/d plus supplemental choline chloride for total choline intakes of 550 (n = 11; 4 with 677CC and 7 with 677TT) or 1100 (n = 12; 4 with 677CC and 8 with 677TT) mg/d for 12 wk. During the last 3 wk, 15% of the total choline intake was provided as d9-choline. Results: Low but measurable enrichments of the choline metabolites were achieved, including that of d3-phosphatidylcholine (d3-PtdCho)—a metabolite produced in the de novo pathway via choline-derived methyl groups. Men with the MTHFR 677TT genotype had a higher urinary enrichment ratio of betaine to choline (P = 0.041), a higher urinary enrichment of sarcosine (P = 0.041), and a greater plasma enrichment ratio of d9-betaine to d9-PtdCho with the 1100 mg choline/d intake (P = 0.033). Conclusion: These data show for the first time in humans that choline itself is a source of methyl groups for de novo PtdCho biosynthesis and indicate that the MTHFR 677TT genotype favors the use of choline as a methyl donor. PMID:21123458

  8. Meta-analyses of Blood Homocysteine Levels for Gender and Genetic Association Studies of the MTHFR C677T Polymorphism in Schizophrenia

    PubMed Central

    Nishi, Akira; Numata, Shusuke; Tajima, Atsushi; Kinoshita, Makoto; Kikuchi, Kumiko; Shimodera, Shinji; Tomotake, Masahito; Ohi, Kazutaka; Hashimoto, Ryota; Imoto, Issei; Takeda, Masatoshi; Ohmori, Tetsuro

    2014-01-01

    Previous studies suggest that elevated blood homocysteine levels and the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism are risk factors for schizophrenia. However, the effects of gender and MTHFR C677T genotypes on blood homocysteine levels in schizophrenia have not been consistent. We first investigated whether plasma total homocysteine levels were higher in patients with schizophrenia than in controls with stratification by gender and by the MTHFR C677T genotypes in a large cohort (N = 1379). Second, we conducted a meta-analysis of association studies between blood homocysteine levels and schizophrenia separately by gender (N = 4714). Third, we performed a case-control association study between the MTHFR C677T polymorphism and schizophrenia (N = 4998) and conducted a meta-analysis of genetic association studies based on Japanese subjects (N = 10 378). Finally, we assessed the effect of plasma total homocysteine levels on schizophrenia by a mendelian randomization approach. The ANCOVA after adjustment for age demonstrated a significant effect of diagnosis on the plasma total homocysteine levels in all strata, and the subsequent meta-analysis for gender demonstrated elevated blood homocysteine levels in both male and female patients with schizophrenia although antipsychotic medication might influence the outcome. The meta-analysis of the Japanese genetic association studies demonstrated a significant association between the MTHFR C677T polymorphism and schizophrenia. The mendelian randomization analysis in the Japanese populations yielded an OR of 1.15 for schizophrenia per 1-SD increase in plasma total homocysteine. Our study suggests that increased plasma total homocysteine levels may be associated with an increased risk of schizophrenia. PMID:24535549

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

    PubMed Central

    Ghaznavi, Habib; Soheili, Zahra; Samiei, Shahram; Soltanpour, Mohammad Soleiman

    2016-01-01

    Purpose: Portal vein thrombosis (PVT) is a rare and life-threatening vascular disorder characterized by obstruction or narrowing of the portal vein. Hyperhomocysteinemia and methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism has been studied in PVT patients with conflicting results. In the present study the association of hyperhomocysteinemia and MTHFR C677T polymorphism with PVT risk was investigated in Iranians. Materials and Methods: Our study population consisted of 10 idiopathic PVT patients and 80 healthy control subjects matched for age and sex. MTHFR C677T polymorphism was genotyped by the polymerase chain reaction technique combined with restriction enzyme fragment length polymorphism (PCR-RFLP) technique and plasma total homocysteine (tHcy) levels were determined by enzyme immunoassay method. Results: Mean plasma tHcy levels were significantly higher in PVT patients (20.2±6.8) than control subjects (10.9±4.7) (P=0.001). Moreover, plasma tHcy levels were significantly higher in 677T allele carriers relative to 677C allele carriers in both PVT patients (P=0.01) and control subjects (P=0.03). Neither homozygote nor heterozygote genotypes of MTHFR C677T polymorphism correlated significantly with PVT risk (P>0.05). Moreover, MTHFR C677T polymorphism didn’t increase the risk of PVT under dominant (CT+TT vs. CC) or recessive (TT vs. CC+CT) genetic models analyzed (P>0.05). The difference in frequency of minor 677T allele between PVT patients and control subjects was not statistically significant (P>0.05). Conclusion: Based on the current study, we suggest that hyperhomocysteinemia constitutes a significant and common risk factor for PVT. Also, MTHFR C677T polymorphism is not a risk factor for PVT but is a contributing factor for elevated plasma tHcy levels. PMID:27051654

  10. Polymorphisms in methylenetetrahydrofolate reductase gene and risk of non-Hodgkin lymphoma in a multi-ethnic population.

    PubMed

    Suthandiram, Sujatha; Gan, Gin Gin; Zain, Shamsul Mohd; Haerian, Batoul Sadat; Bee, Ping Chong; Lian, Lay Hoong; Chang, Kian Meng; Ong, Tee Chuan; Mohamed, Zahurin

    2014-05-01

    An imbalance in folate metabolism can adversely affect DNA synthesis and methylation systems which can lead to susceptibility to non-Hodgkin lymphoma (NHL). Whether single nucleotide polymorphisms (SNPs) and their haplotypes in the methylenetetrahydrofolate reductase (MTHFR) are associated with NHL, remain inconclusive. We investigated the association between MTHFR C677T and A1298C SNPs and NHL risk in a population which is made up of Malay, Chinese and Indian ethnic subgroups. A total of 372 NHL patients and 722 controls were genotyped using the Sequenom MassARRAY platform. Our results of the pooled subjects failed to demonstrate significant association between the MTHFR C677T and A1298C SNPs with NHL and its subtypes. The results were in agreement with the previous meta-analyses. In the Indian ethnic subgroup however, single locus analysis of MTHFR A1298C appears to confer risk to NHL (Odds ratio (OR) 1.91, 95% confidence interval (95% CI) 1.22-3.00, P=0.006). The risk is almost doubled in homozygous carrier of MTHFR 1298CC (OR 4.03, 95% CI 1.56-10.43, P=0.004). Haplotype analysis revealed higher frequency of CC in the Indian NHL patients compared with controls (OR 1.86, 95% CI 1.18-2.93, P=0.007). There is lack of evidence to suggest an association between MTHFR C677T and A1298C with the risk of NHL in the Malays and Chinese. In the Indians however, the MTHFR A1298C confers risk to NHL. This study suggests ethnicity modifies the relationship between polymorphisms in the folate-metabolizing gene and NHL. PMID:24646728

  11. Polymorphisms of 5,10-methylenetetrahydrofolate reductase and thymidylate synthase, dietary folate intake, and the risk of leukemia in adults.

    PubMed

    Liu, Ping; Zhang, Min; Xie, Xing; Jin, Jie; Holman, C D'Arcy J

    2016-03-01

    The 5,10-methylenetetrahydrofolate reductase (MTHFR) and thymidylate synthase (TS) are critical enzymes in folate metabolism. Previous studies have reported conflicting results on the associations between MTHFR/TS polymorphisms and adult leukemia risk, which may due to the lack of information on folate intake. We investigated the risks of adult leukemia with genetic polymorphisms of folate metabolic enzymes (MTHFR C677T, A1298C, and TS) and evaluated if the associations varied by dietary folate intake from a multicenter case-control study conducted in Chinese. This study comprised 442 incident adult leukemia cases and 442 outpatient controls, individually matched to cases by gender, birth quinquennium, and study site. Genotypes were determined by a polymerase chain reaction (PCR) or PCR-based restriction fragment length polymorphism assay. Dietary folate intake was assessed by face-to-face interviews using a validated food-frequency questionnaire. The MTHFR 677TT genotype conferred a significant higher risk of leukemia in males than in females and exhibited an increased risk of acute myeloid leukemia (AML) but a decreased risk of acute lymphoblastic leukemia (ALL). The MTHFR 1298AC genotype appeared to decrease the risks of leukemia in both genders, in AML and ALL. Stratified analysis by dietary folate intake showed the increased risks of leukemia with the MTHFR 677TT and TS 2R3R/2R2R genotypes were only significant in individuals with low folate intake. A significant interaction between TS polymorphism and dietary folate intake was observed (P = 0.03). This study suggests that dietary folate intake and gender may modify the associations between MTHFR/TS polymorphisms and adult leukemia risk. PMID:26438060

  12. Methylenetetrahydrofolate reductase C677T and A1298C polymorphisms and fluorouracil-based treatment in Taiwan colorectal cancer.

    PubMed

    Wu, Nai-Chun; Su, Shih-Ming; Lin, Tai-Jung; Chin, Jen; Hou, Chun-Fang; Yang, Jhong-Ying; Liu, Wen-Sheng; Chang, Li-Ching

    2015-09-01

    This study aimed to investigate the association between methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and the prognosis of colorectal cancer (CRC) patients undergoing 5-fluorouracil (5-FU)-based chemotherapy in Taiwan. We investigated 126 CRC cases. The most common polymorphisms C677T (rs1801133) and A1298C (rs1801131) in MTHFR were genotyped using PCR-restriction fragment length polymorphism. The frequencies of C677T and A1298C were further compared with those in the HapMap database for Whites and Asians. In this study, we found that TT-homozygosity at MTHFR C677T was significantly associated with survival in CRC patients [P<0.001; 95% confidence interval (CI)=0.068-0.212]. In CRC patients receiving 5-FU-based chemotherapy, the TT genotype at C677T was also significantly associated with survival (P=0.001; 95% CI=0.113-0.400) and recurrence after surgery (P<0.001; 95% CI=0.295-0.609). The A1298C genotypes had a significant impact on survival (χ=7.103; P=0.029). The MTHFR A1298C CC genotype may increase the risk of death in Taiwanese CRC patients. The MTHFR C677T TT genotype was present at a lower frequency in our CRC patients than in the HapMap Asian population, but the frequency was similar to that in Whites in the HapMap database. The distribution of MTHFR A1298C genotypes was similar in our CRC and in the HapMap Asian population, but was different from that in the White population. This study suggested that MTHFR C677T and A1298C are associated with prognosis in CRC patients undergoing 5-FU-based chemotherapy. PMID:26111049

  13. Association of Methylenetetrahydrofolate Reductase C677T Polymorphism with Hyperhomocysteinemia and Deep Vein Thrombosis in the Iranian Population

    PubMed Central

    Ghaznavi, Habib; Soheili, Zahra; Samiei, Shahram; Soltanpour, Mohammad Soleiman

    2015-01-01

    Purpose: Deep venous thrombosis (DVT) is a common but elusive condition characterized by a high morbidity and mortality rate. The aim of the present study was to investigate the correlation between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism with plasma total homocysteine (tHcy) levels and DVT risk in an Iranian population. Materials and Methods: Our study population consisted of 67 patients with a diagnosis of DVT and 67 healthy subjects as controls. Genotyping of MTHFR C677T polymorphism was performed by the polymerase chain reaction technique combined with restriction enzyme fragment length polymorphism (PCR-RFLP) and measurement of tHcy levels was done by enzyme immunoassay method. Results: Plasma tHcy levels were significantly higher in DVT patients than controls (18.09±7.6 vs. 10.5±4.3, P=0.001). Also, plasma tHcy levels were significantly higher in MTHFR 677TT genotypes compared to 677CC genotypes in both DVT patients (P=0.016) and controls (P=0.03). Neither heterozygote nor homozygote genotypes of MTHFR C677T polymorphism was significantly correlated with DVT (P>0.05). The distribution of MTHFR C677T genotypes was similar between men and women in both DVT patients and controls (P>0.05). Moreover, the frequency of mutant 677T allele did not differ significantly between the two groups (28.3% vs. 21.6%, P=0.15). Conclusion: Based on this study, we propose that hyperhomocysteinemia but not homozygosity for MTHFR C677T polymorphism is a significant risk factor for DVT in the Iranian population. Also, MTHFR 677TT genotype is a determinant of elevated plasma tHcy levels. PMID:26719836

  14. Sex Differences in Ethanol's Anxiolytic Effect and Chronic Ethanol Withdrawal Severity in Mice with a Null Mutation of the 5α-Reductase Type 1 Gene.

    PubMed

    Tanchuck-Nipper, Michelle A; Ford, Matthew M; Hertzberg, Anna; Beadles-Bohling, Amy; Cozzoli, Debra K; Finn, Deborah A

    2015-05-01

    Manipulation of endogenous levels of the GABAergic neurosteroid allopregnanolone alters sensitivity to some effects of ethanol. Chronic ethanol withdrawal decreases activity and expression of 5α-reductase-1, an important enzyme in allopregnanolone biosynthesis encoded by the 5α-reductase-1 gene (Srd5a1). The present studies examined the impact of Srd5a1 deletion in male and female mice on several acute effects of ethanol and on chronic ethanol withdrawal severity. Genotype and sex did not differentially alter ethanol-induced hypothermia, ataxia, hypnosis, or metabolism, but ethanol withdrawal was significantly lower in female versus male mice. On the elevated plus maze, deletion of the Srd5a1 gene significantly decreased ethanol's effect on total entries versus wildtype (WT) mice and significantly decreased ethanol's anxiolytic effect in female knockout (KO) versus WT mice. The limited sex differences in the ability of Srd5a1 genotype to modulate select ethanol effects may reflect an interaction between developmental compensations to deletion of the Srd5a1 gene with sex hormones and levels of endogenous neurosteroids. PMID:25355320

  15. Sex Differences in Ethanol’s Anxiolytic Effect and Chronic Ethanol Withdrawal Severity in Mice With a Null Mutation of the 5α-Reductase Type 1 Gene

    PubMed Central

    Tanchuck-Nipper, Michelle A.; Ford, Matthew M.; Hertzberg, Anna; Beadles-Bohling, Amy; Cozzoli, Debra K.; Finn, Deborah A.

    2015-01-01

    Manipulation of endogenous levels of the GABAergic neurosteroid allopregnanolone alters sensitivity to some effects of ethanol. Chronic ethanol withdrawal decreases activity and expression of 5α-reductase-1, an important enzyme in allopregnanolone biosynthesis encoded by the 5α-reductase-1 gene (Srd5a1). The present studies examined the impact of Srd5a1 deletion in male and female mice on several acute effects of ethanol and on chronic ethanol withdrawal severity. Genotype and sex did not differentially alter ethanol-induced hypothermia, ataxia, hypnosis, or metabolism, but ethanol withdrawal was significantly lower in female versus male mice. On the elevated plus maze, deletion of the Srd5a1 gene significantly decreased ethanol’s effect on total entries versus wildtype (WT) mice and significantly decreased ethanol’s anxiolytic effect in female knockout (KO) versus WT mice. The limited sex differences in the ability of Srd5a1 genotype to modulate select ethanol effects may reflect an interaction between developmental compensations to deletion of the Srd5a1 gene with sex hormones and levels of endogenous neurosteroids. PMID:25355320

  16. The maize brown midrib2 (bm2) gene encodes a methylenetetrahydrofolate reductase that contributes to lignin accumulation

    PubMed Central

    Tang, Ho Man; Liu, Sanzhen; Hill-Skinner, Sarah; Wu, Wei; Reed, Danielle; Yeh, Cheng-Ting; Nettleton, Dan; Schnable, Patrick S

    2014-01-01

    The midribs of maize brown midrib (bm) mutants exhibit a reddish-brown color associated with reductions in lignin concentration and alterations in lignin composition. Here, we report the mapping, cloning, and functional and biochemical analyses of the bm2 gene. The bm2 gene was mapped to a small region of chromosome 1 that contains a putative methylenetetrahydrofolate reductase (MTHFR) gene, which is down-regulated in bm2 mutant plants. Analyses of multiple Mu-induced bm2-Mu mutant alleles confirmed that this constitutively expressed gene is bm2. Yeast complementation experiments and a previously published biochemical characterization show that the bm2 gene encodes a functional MTHFR. Quantitative RT-PCR analyses demonstrated that the bm2 mutants accumulate substantially reduced levels of bm2 transcript. Alteration of MTHFR function is expected to influence accumulation of the methyl donor S-adenosyl-l-methionine (SAM). Because SAM is consumed by two methyltransferases in the lignin pathway (Ye et al., 1994), the finding that bm2 encodes a functional MTHFR is consistent with its lignin phenotype. Consistent with this functional assignment of bm2, the expression patterns of genes in a variety of SAM-dependent or -related pathways, including lignin biosynthesis, are altered in the bm2 mutant. Biochemical assays confirmed that bm2 mutants accumulate reduced levels of lignin with altered composition compared to wild-type. Hence, this study demonstrates a role for MTHFR in lignin biosynthesis. PMID:24286468

  17. New insights into the catalytic mechanism of vitamin K epoxide reductase (VKORC1) – The catalytic properties of the major mutations of rVKORC1 explain the biological cost associated to mutations☆

    PubMed Central

    Matagrin, Benjamin; Hodroge, Ahmed; Montagut-Romans, Adrien; Andru, Julie; Fourel, Isabelle; Besse, Stéphane; Benoit, Etienne; Lattard, Virginie

    2013-01-01

    The systematic use of antivitamin K anticoagulants (AVK) as rodenticides caused the selection of rats resistant to AVKs. The resistance is mainly associated to genetic polymorphisms in the Vkorc1 gene encoding the VKORC1 enzyme responsible for the reduction of vitamin K 2,3-epoxide to vitamin K. Five major mutations, which are responsible for AVK resistance, have been described. Possible explanations for the biological cost of these mutations have been suggested. This biological cost might be linked to an increase in the vitamin K requirements. To analyze the possible involvement of VKORC1 in this biological cost, rVKORC1 and its major mutants were expressed in Pichia pastoris as membrane-bound proteins and their catalytic properties were determined for vitamin K and 3-OH-vitamin K production. In this report, we showed that mutations at Leu-120 and Tyr-139 dramatically affect the vitamin K epoxide reductase activity. Moreover, this study allowed the detection of an additional production of 3-hydroxyvitamin K for all the mutants in position 139. This result suggests the involvement of Tyr-139 residue in the second half-step of the catalytic mechanism corresponding to the dehydration of vitamin K epoxide. As a consequence, the biological cost observed in Y139C and Y139S resistant rat strains is at least partially explained by the catalytic properties of the mutated VKORC1 involving a loss of vitamin K from the vitamin K cycle through the formation of 3-hydroxyvitamin K and a very low catalytic efficiency of the VKOR activity. PMID:23772386

  18. A common variant in MTHFR influences response to chemoradiotherapy and recurrence of rectal cancer

    PubMed Central

    Nikas, Jason B; Lee, Janet T; Maring, Elizabeth D; Washechek-Aletto, Jill; Felmlee-Devine, Donna; Johnson, Ruth A; Smyrk, Thomas C; Tawadros, Patrick S; Boardman, Lisa A; Steer, Clifford J

    2015-01-01

    An important determinant of the pathogenesis and prognosis of various diseases is inherited genetic variation. Single-nucleotide polymorphisms (SNPs), variations at a single base position, have been identified in both protein-coding and noncoding DNA sequences, but the vast majority of millions of those variants are far from being functionally understood. Here we show that a common variant in the gene MTHFR [rs1801133 (C>T)] not only influences response to neoadjuvant chemoradiotherapy in patients with rectal cancer, but it also influences recurrence of the disease itself. More specifically, patients with the homozygous ancestral (wild type) genotype (C/C) were 2.91 times more likely (291% increased benefit) to respond to neoadjuvant chemoradiotherapy {95% CI: [1.23, 6.89]; P=0.0150} and 3.25 times more likely (325% increased benefit) not to experience recurrence of the disease {95% CI: [1.37, 7.72]; P=0.0079} than patients with either the heterozygous (C/T) or the homozygous mutation (T/T) genotype. These results identify MTHFR as an important genetic marker and open up new, pharmacogenomic strategies in the treatment and management of rectal cancer. PMID:26693073

  19. Rat lens aldehyde reductase.

    PubMed

    Sato, S; Kador, P F

    1989-07-01

    Aldehyde reductase (E.C. 1.1.1.2) has been purified to apparent homogeneity from rat lens and its properties have been compared to those of both rat lens aldose reductase and rat kidney aldehyde reductase. The purification was accomplished by ammonium sulfate fractionation, Sephadex G-75 chromatography, affinity chromatography on Amicon Matrex Gel Orange A and chromatofocusing. The purified enzyme is distinct from rat lens aldose reductase but appears similar to rat kidney aldehyde reductase in molecular weight, immunological properties and substrate specificities. Rat lens aldehyde reductase is inhibited by a number of aldose reductase inhibitors; however, its susceptibility to inhibition is more similar to rat kidney aldehyde reductase than to rat lens aldose reductase. PMID:2501231

  20. Role of MTHFR C677T gene polymorphism in the susceptibility of schizophrenia: An updated meta-analysis.

    PubMed

    Yadav, Upendra; Kumar, Pradeep; Gupta, Sanjay; Rai, Vandana

    2016-04-01

    Methylenetetrahydrofolate reductase (MTHFR) is the key enzyme of folate/homocysteine metabolic pathway. C677T polymorphism of MTHFR gene was reported as risk factor for congenital defects, metabolic and neuropsychiatric disorders. Numerous case-control studies investigated C677T polymorphism as risk factor for schizophrenia but results of these studies were contradictory. To draw a conclusion, a meta-analysis of all available case-control studies was performed. PubMed, Google Scholar, Springer Link and Elsevier databases were searched for eligible case-control studies. Pooled odds ratio with 95%CI was used as an association measure and all statistical analyses were performed by Open Meta-Analyst and MIX software. Total 38 studies with 10,069 cases and 13,372 controls were included in the present meta-analysis. Results of meta-analysis showed significant associated between C677T polymorphism and risk of schizophrenia (ORTvsC=1.18, 95%CI=1.10-1.27, p=<0.001; ORCTvsCC=1.10, 95%CI=1.04-1.17, p=<0.001; ORTTvsCC=1.40, 95%CI=1.20-1.64, p=<0.001; ORTT+CTvsCC=1.19, 95%CI=1.09-1.30, p=<0.001). We also performed subgroup and sensitivity analyses. Subgroup analysis was done according to ethnicity and significant association was found between C677T polymorphism and risk of schizophrenia in all three ethnic populations-African (OR=2.51; 95%CI=1.86-3.40; p=<0.001), Asian (OR=1.21; 95%CI=1.10-1.33; p=<0.001) and Caucasian (OR=1.07; 95%CI=1.01-1.14; p=0.01). In conclusion the results of the present meta-analysis suggested that the MTHFR C677T polymorphism is a risk factor for schizophrenia. PMID:27025471

  1. Methylenetetrahydrofolate reductase gene polymorphisms and skin cancer risk: a meta-analysis.

    PubMed

    Deng, Feng; Gao, Ying; L V, Ju-hong; Gao, Jian-min

    2014-01-01

    We sought to determine whether the methylenetetrahydrofolate reductase (MTHFR) A1298C and C677T polymorphisms are associated with increased skin cancer risk. We performed literature searches of the PubMed, BIOSIS Previews, and Web of Science databases to identify eligible articles published through September 15, 2013. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using fixed-effects or random-effects models. Publication bias and subgroup analyses were also performed. Eight articles, which consisted of 10,066 subjects (2,672 patients and 7,394 controls), were included in the meta-analysis. Homozygous MTHFR 1298C individuals were 1.29 times more likely to develop skin cancer (95% CI, 1.04-1.61) compared with A1298C allele (AA or AC) carriers. There was an increased risk for C allele homozygotes compared with the 1,298 AA+AC carriers (OR, 1.45; 95% CI, 1.08-1.96) when restricted to basal cell carcinomas (BCC). The 1298C homozygote carriers increased the odds of BCC by 1.47 times (95% CI, 1.07-2.01) compared with those who were 1298A homozygote carriers. ORs for all genetic models yielded a null association. The data obtained from this meta-analysis suggest that the MTHFR 1298C allele is associated with increased skin cancer risk, particularly BCC; however, no association was observed between the MTHFR C677T polymorphism and skin cancer. PMID:25306137

  2. Mutation of the Heme Axial Ligand of Escherichia coli Succinate-Quinone Reductase: Implications for Heme Ligation in Mitochondrial Complex II from Yeast

    PubMed Central

    Maklashina, Elena; Rajagukguk, Sany; McIntire, William S.; Cecchini, Gary

    2010-01-01

    A b-type heme is conserved in membrane-bound complex II enzymes (SQR, succinate-ubiquinone reductase). The axial ligands for the low spin heme b in Escherichia coli complex II are SdhC His84 and SdhD His71. E. coli SdhD His71 is separated by 10 residues from SdhD Asp82 and Tyr83 which are essential for ubiquinone catalysis. The same His-10x-AspTyr motif dominates in homologous SdhD proteins, except for Saccharomyces cerevisiae where a tyrosine is at the axial position (Tyr-Cys-9x-AspTyr). Nevertheless, the yeast enzyme was suggested to contain a stoichiometric amount of heme, however, with the Cys ligand in the aforementioned motif acting as heme ligand. In this report, the role of Cys residues for heme coordination in the complex II family of enzymes is addressed. Cys was substituted to the SdhD-71 position and the yeast Tyr71Cys72 motif also recreated. The Cys71 variant retained heme, although it was high spin, while the Tyr71Cys72 mutant lacked heme. Previously the presence of heme in S. cerevisiae was detected by a spectral peak in fumarate-oxidized, dithionite-reduced mitochondria. Here it is shown that this method must be used with caution. Comparison of bovine and yeast mitochondrial membranes shows that fumarate induced reoxidation of cytochromes in both SQR and the bc1 complex (ubiquinol-cytochrome c reductase). Thus, this report raises a concern about the presence of low spin heme b in S. cerevisiae complex II. PMID:20100456

  3. MTHFR C677T and A1298C polymorphisms as predictors of radiotherapy response in head and neck squamous cell carcinoma.

    PubMed

    Anders, Q S; Stur, E; Agostini, L P; Garcia, F M; Reis, R S; Santos, J A; Mendes, S O; Maia, L L; Peterle, G T; Stange, V; Carvalho, M B; Tajara, E H; Santos, M; Silva-Conforti, A M A; Louro, I D

    2015-01-01

    The C677T and A1298C polymorphisms in methylene-tetrahydrofolate reductase (MTHFR), which regulates the release of active folate in the body, may have reduced activity. Given that folate participates in important intracellular pathways, such as nucleotide synthesis and biomolecule methylation, it seems plausible that patients with head and neck squamous cell carcinoma (HNSCC) may respond differently to radiotherapy treatments, based on genetic polymor-phisms. Therefore, this study sought to understand the role of these polymorphisms in HNSCC patient radiotherapy response. Genotypes were detected by PCR-RFLP after extraction of DNA from peripheral blood lymphocytes. Survival curves were analyzed by the Kaplan- Meier model, and significant differences were analyzed by the Wil-coxon test. Response to radiotherapy in patients with laryngeal SCC was significantly associated with the MTHFR C677T polymorphism (P = 0.030). Indeed, the presence of at least one T allele decreases the mortality rate up to 3-fold. Therefore, we propose that MTHFR C677T may represent a putative biomarker for radiotherapy prognosis in la-ryngeal SCC patients. PMID:26535623

  4. Role of genetic mutations in folate-related enzyme genes on Male Infertility

    PubMed Central

    Liu, Kang; Zhao, Ruizhe; Shen, Min; Ye, Jiaxin; Li, Xiao; Huang, Yuan; Hua, Lixin; Wang, Zengjun; Li, Jie

    2015-01-01

    Several studies showed that the genetic mutations in the folate-related enzyme genes might be associated with male infertility; however, the results were still inconsistent. We performed a meta-analysis with trial sequential analysis to investigate the associations between the MTHFR C677T, MTHFR A1298C, MTR A2756G, MTRR A66G mutations and the MTHFR haplotype with the risk of male infertility. Overall, a total of 37 studies were selected. Our meta-analysis showed that the MTHFR C677T mutation was a risk factor for male infertility in both azoospermia and oligoasthenoteratozoospermia patients, especially in Asian population. Men carrying the MTHFR TC haplotype were most liable to suffer infertility while those with CC haplotype had lowest risk. On the other hand, the MTHFR A1298C mutation was not related to male infertility. MTR A2756G and MTRR A66G were potential candidates in the pathogenesis of male infertility, but more case-control studies were required to avoid false-positive outcomes. All of these results were confirmed by the trial sequential analysis. Finally, our meta-analysis with trial sequential analysis proved that the genetic mutations in the folate-related enzyme genes played a significant role in male infertility. PMID:26549413

  5. Role of genetic mutations in folate-related enzyme genes on Male Infertility.

    PubMed

    Liu, Kang; Zhao, Ruizhe; Shen, Min; Ye, Jiaxin; Li, Xiao; Huang, Yuan; Hua, Lixin; Wang, Zengjun; Li, Jie

    2015-01-01

    Several studies showed that the genetic mutations in the folate-related enzyme genes might be associated with male infertility; however, the results were still inconsistent. We performed a meta-analysis with trial sequential analysis to investigate the associations between the MTHFR C677T, MTHFR A1298C, MTR A2756G, MTRR A66G mutations and the MTHFR haplotype with the risk of male infertility. Overall, a total of 37 studies were selected. Our meta-analysis showed that the MTHFR C677T mutation was a risk factor for male infertility in both azoospermia and oligoasthenoteratozoospermia patients, especially in Asian population. Men carrying the MTHFR TC haplotype were most liable to suffer infertility while those with CC haplotype had lowest risk. On the other hand, the MTHFR A1298C mutation was not related to male infertility. MTR A2756G and MTRR A66G were potential candidates in the pathogenesis of male infertility, but more case-control studies were required to avoid false-positive outcomes. All of these results were confirmed by the trial sequential analysis. Finally, our meta-analysis with trial sequential analysis proved that the genetic mutations in the folate-related enzyme genes played a significant role in male infertility. PMID:26549413

  6. Conversion of Human Steroid 5[beta]-Reductase (AKR1D1) into 3[beta]-Hydroxysteroid Dehydrogenase by Single Point Mutation E120H: Example of Perfect Enzyme Engineering

    SciTech Connect

    Chen, Mo; Drury, Jason E.; Christianson, David W.; Penning, Trevor M.

    2012-10-10

    Human aldo-keto reductase 1D1 (AKR1D1) and AKR1C enzymes are essential for bile acid biosynthesis and steroid hormone metabolism. AKR1D1 catalyzes the 5{beta}-reduction of {Delta}{sup 4}-3-ketosteroids, whereas AKR1C enzymes are hydroxysteroid dehydrogenases (HSDs). These enzymes share high sequence identity and catalyze 4-pro-(R)-hydride transfer from NADPH to an electrophilic carbon but differ in that one residue in the conserved AKR catalytic tetrad, His120 (AKR1D1 numbering), is substituted by a glutamate in AKR1D1. We find that the AKR1D1 E120H mutant abolishes 5{beta}-reductase activity and introduces HSD activity. However, the E120H mutant unexpectedly favors dihydrosteroids with the 5{alpha}-configuration and, unlike most of the AKR1C enzymes, shows a dominant stereochemical preference to act as a 3{beta}-HSD as opposed to a 3{alpha}-HSD. The catalytic efficiency achieved for 3{beta}-HSD activity is higher than that observed for any AKR to date. High resolution crystal structures of the E120H mutant in complex with epiandrosterone, 5{beta}-dihydrotestosterone, and {Delta}{sup 4}-androstene-3,17-dione elucidated the structural basis for this functional change. The glutamate-histidine substitution prevents a 3-ketosteroid from penetrating the active site so that hydride transfer is directed toward the C3 carbonyl group rather than the {Delta}{sup 4}-double bond and confers 3{beta}-HSD activity on the 5{beta}-reductase. Structures indicate that stereospecificity of HSD activity is achieved because the steroid flips over to present its {alpha}-face to the A-face of NADPH. This is in contrast to the AKR1C enzymes, which can invert stereochemistry when the steroid swings across the binding pocket. These studies show how a single point mutation in AKR1D1 can introduce HSD activity with unexpected configurational and stereochemical preference.

  7. Association between Hcy levels and the CBS844ins68 and MTHFR C677T polymorphisms with essential hypertension

    PubMed Central

    CAI, WEIJUAN; YIN, LIANG; YANG, FANG; ZHANG, LEI; CHENG, JIANG

    2014-01-01

    The aim of the present study was to investigate the association between the homocysteine (Hcy) levels and polymorphisms of the CBS844ins68 and MTHFR C677T genes in essential hypertension (EH). The effects of the MTHFR C677T and CBS844ins68 haploid genotypes and the combined genotypes on EH and levels of Hcy were further explored. The polymorphisms of CBS844ins68 and MTHFR C677T genes in 200 EH and 200 normal tensive (NT) patients were detected using polymerase chain reaction-restriction fragment length polymorphism and analysis of the distribution of genotypes. An automated biochemical analyzer was used to measure the plasma Hcy levels and the clinical biochemistry data. The plasma Hcy levels in EH were significantly higher than those of the NT group (P<0.05). There were no significant differences (P>0.05) between males and females. Two genotypes, deletion/deletion (DD) and deletion/insertion (DI), of the CBS844ins68 polymorphism were found in two groups with no clear differences in two genotypes and allele frequency distribution (P>0.05). There were significant differences in the three genotype frequencies (?2=6.658, ?2=4.410, P<0.05) for MTHFR C677T locus genotypes CC, CT and TT. The Hcy levels in genotypes DD and DI had no significant differences (P>0.05) and the CT and TT types were significantly higher compared to the CC genotype (P<0.05). The CC/DD combined genotype in the two groups was significantly different (P<0.05), and the odds ratio (OR), 0.569 showed that the CC/DD genotype may be a protective factor of hypertension. In the two groups, the Hcy levels for combined genotypes CC/DD, CT/DD, TT/DD and TT/DI were significantly different (P<0.05). The SHEsis software analysis linkage disequilibrium coefficient=0.216, indicates that there is probably a weak linkage for MTHFR C677T and CBS844ins68. Haplotype analysis suggested that the C-D haplotype was negatively correlated with EH (OR, 0.727) and that there was a positive correlation between T-D haplotype and EH (OR, 1.376). MTHFR C677T and CBS844ins68 polymorphisms were present in the populations studied and the CBS844ins68 homozygous mutation was not present. Therefore, there is a correlation between the polymorphisms of the MTHFR C677T gene and EH, and allele T may be one of the predisposing factors. MTHFR C677T and CBS844ins68 may exist with a certain linkage and the T-D haplotype may be a risk factor for EH. PMID:25279160

  8. Association between Hcy levels and the CBS844ins68 and MTHFR C677T polymorphisms with essential hypertension.

    PubMed

    Cai, Weijuan; Yin, Liang; Yang, Fang; Zhang, Lei; Cheng, Jiang

    2014-11-01

    The aim of the present study was to investigate the association between the homocysteine (Hcy) levels and polymorphisms of the CBS844ins68 and MTHFR C677T genes in essential hypertension (EH). The effects of the MTHFR C677T and CBS844ins68 haploid genotypes and the combined genotypes on EH and levels of Hcy were further explored. The polymorphisms of CBS844ins68 and MTHFR C677T genes in 200 EH and 200 normal tensive (NT) patients were detected using polymerase chain reaction-restriction fragment length polymorphism and analysis of the distribution of genotypes. An automated biochemical analyzer was used to measure the plasma Hcy levels and the clinical biochemistry data. The plasma Hcy levels in EH were significantly higher than those of the NT group (P<0.05). There were no significant differences (P>0.05) between males and females. Two genotypes, deletion/deletion (DD) and deletion/insertion (DI), of the CBS844ins68 polymorphism were found in two groups with no clear differences in two genotypes and allele frequency distribution (P>0.05). There were significant differences in the three genotype frequencies (?(2)=6.658, ?(2)=4.410, P<0.05) for MTHFR C677T locus genotypes CC, CT and TT. The Hcy levels in genotypes DD and DI had no significant differences (P>0.05) and the CT and TT types were significantly higher compared to the CC genotype (P<0.05). The CC/DD combined genotype in the two groups was significantly different (P<0.05), and the odds ratio (OR), 0.569 showed that the CC/DD genotype may be a protective factor of hypertension. In the two groups, the Hcy levels for combined genotypes CC/DD, CT/DD, TT/DD and TT/DI were significantly different (P<0.05). The SHEsis software analysis linkage disequilibrium coefficient=0.216, indicates that there is probably a weak linkage for MTHFR C677T and CBS844ins68. Haplotype analysis suggested that the C-D haplotype was negatively correlated with EH (OR, 0.727) and that there was a positive correlation between T-D haplotype and EH (OR, 1.376). MTHFR C677T and CBS844ins68 polymorphisms were present in the populations studied and the CBS844ins68 homozygous mutation was not present. Therefore, there is a correlation between the polymorphisms of the MTHFR C677T gene and EH, and allele T may be one of the predisposing factors. MTHFR C677T and CBS844ins68 may exist with a certain linkage and the T-D haplotype may be a risk factor for EH. PMID:25279160

  9. Association between the MTHFR C677T polymorphism and gastric cancer susceptibility: A meta-analysis of 5,757 cases and 8,501 controls

    PubMed Central

    CHEN, LONG; LU, NING; ZHANG, BAI-HONG; WENG, LI; LU, JUN

    2015-01-01

    Current data regarding the association between the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and the risk of developing gastric cancer are insufficient to draw definite conclusions. Therefore, the present meta-analysis was conducted to achieve a more precise estimation of the association. MEDLINE, EMBASE and Wanfang database searches resulted in the identification of 28 eligible studies describing 5,757 cases and 8,501 controls. The strength of the association between the MTHFR C677T polymorphism and gastric cancer risk were evaluated using crude odds ratios (ORs), with 95% confidence intervals (CIs). The pooled ORs were determined using homozygous (TT vs. CC), heterozygous (CT vs. CC), dominant (TT+CT vs. CC) and recessive (TT vs. CC+CT) models. When all studies were pooled into the meta-analysis, significant associations were identified between the MTHFR C677T polymorphism and the risk of gastric cancer (homozygous model: OR, 1.39; 95% CI, 1.20–1.62; heterozygous model: OR, 1.18; 95% CI, 1.05–1.32; dominant model: OR, 1.23; 95% CI, 1.10–1.38; recessive model: OR, 1.26; 95% CI, 1.12–1.42). Stratification of the data by ethnicity identified a statistically significantly elevated risk of gastric cancer in Asian MTHFR C677T polymorphism populations (homozygous model: OR, 1.64; 95% CI, 1.43–1.90; heterozygous model: OR, 1.30; 95% CI, 1.16–1.45; dominant model: OR, 1.39; 95% CI, 1.25–1.54; recessive model: OR, 1.41; 95% CI, 1.25–1.51), but not in Caucasian populations (homozygous model: OR, 1.15; 95% CI, 0.89–1.48; heterozygous model: OR, 1.03; 95% CI, 0.84–1.25; dominant model: OR, 1.05; 95% CI, 0.86–1.28; recessive model: OR, 1.09; 95% CI, 0.91–1.31). Following adjustment for heterogeneity, the current meta-analysis demonstrated that the MTHFR C677T polymorphism was not associated with the risk of gastric cancer in Caucasian individuals. Furthermore, no evidence of publication bias was observed. Thus, the current meta-analysis indicates that the MTHFR C677T allele may be a low-penetrant risk factor for the development of gastric cancer in Asian populations. PMID:26622644

  10. Genetic interactions between MTHFR (C677T), methionine synthase (A2756G, C2758G) variants with vitamin B12 and folic acid determine susceptibility to premature coronary artery disease in Indian population

    PubMed Central

    Kanth, V. V. Ravi; Golla, Jaya Prakash; Sastry, B. K. S; Naik, Sudhir; Kabra, Nitin; Sujatha, Madireddi

    2011-01-01

    Background: Researchers have determined that Indians face a higher risk of heart disease, despite the fact that nearly half of them are vegetarians and lack many of the other traditional risk factors. In the below-30 age group, coronary artery disease mortality among Indians is three-fold higher than in the whites in United Kingdom and ten-fold higher than the Chinese in Singapore. High levels of homocysteine have been widely linked to the early onset of heart diseases in other populations, although a definite proof among Indians is lacking, which needs to be investigated by way of screening for factors responsible for high homocysteine levels. Objective: To screen for genetic factors responsible for hyperhomocysteinemia and the risk for premature coronary artery disease. Materials and Methods: A total of 100 individuals with proven premature coronary artery disease and 200 age-and-sex matched controls were screened for polymorphisms in Methylenetetrahydrofolate reductase (MTHFR) (C677T) Methionine synthase (MS) genes (A2756G, C2758G), and the B12 and Folate levels were estimated. Results: Results from the mutational analysis revealed that in the study group, seven individuals had a polymorphism for the C677T allele in the MTHFR gene (one homozygous and six heterozygous) (Fischer's Exact test P > 0.046) (OR: 0.2711 95% CI 0.0774 to 0.9491). Six were heterozygous for the A2756G polymorphism in the MS gene (Fischer's Exact test P > 0.0012). None showed a polymorphism at the C2758G allele in the MS gene. Four controls showed heterozygosity for the C677T polymorphism and none for the MS gene. The B12 and Folate levels were significantly lower in the study group as compared to the controls. Conclusions: It is important to know which factors determine the total homocysteine concentrations. In the general population, the most important modifiable determinants of tHcy are folate intake and coffee consumption. Smoking and alcohol consumption are also associated with the total homocysteine concentrations, but more research is necessary to elucidate whether these relations are not originating from residual confounding due to other lifestyle factors. PMID:22022143

  11. Mutation of alkyl hydroperoxide reductase gene ahpC of Xanthomonas oryzae pv. oryzae affects hydrogen peroxide accumulation during the rice-pathogen interaction.

    PubMed

    Li, Xin; Qiao, Jiaju; Yang, Lipeng; Li, Xinling; Qiao, Suyu; Pang, Xinyue; Tian, Fang; Chen, Huamin; He, Chenyang

    2014-10-01

    Hydrogen peroxide (H2O2) is usually generated by normal aerobic respiration of pathogens and by the host defense response during plant-pathogen interactions. In this study, histochemical localization of H2O2 accumulation in rice inoculated with the wild-type strain (PXO99(A)) and the gene deletion mutant (ΔahpC) of alkyl hydroperoxide reductase subunit C (AhpC) of Xanthomonas oryzae pv. oryzae (Xoo), the bacterial blight pathogen of rice, was analyzed. The ΔahpC mutant displayed a significant decrease in endogenous H2O2 accumulation which was induced by the compensatory increase in H2O2 scavenging activity. The change in the bacterial endogenous H2O2 level affected the total amount of H2O2 accumulation during the interaction with rice plants. These results suggested that Xoo contributes to H2O2 accumulation in rice in a compatible interaction, and pathogen-driving H2O2 is in association with cell collapse of rice. PMID:25084557

  12. Nitrate reductase mutation alters potassium nutrition as well as nitric oxide-mediated control of guard cell ion channels in Arabidopsis.

    PubMed

    Chen, Zhong-Hua; Wang, Yizhou; Wang, Jian-Wen; Babla, Mohammad; Zhao, Chenchen; García-Mata, Carlos; Sani, Emanuela; Differ, Christopher; Mak, Michelle; Hills, Adrian; Amtmann, Anna; Blatt, Michael R

    2016-03-01

    Maintaining potassium (K(+) ) nutrition and a robust guard cell K(+) inward channel activity is considered critical for plants' adaptation to fluctuating and challenging growth environment. ABA induces stomatal closure through hydrogen peroxide and nitric oxide (NO) along with subsequent ion channel-mediated loss of K(+) and anions. However, the interactions of NO synthesis and signalling with K(+) nutrition and guard cell K(+) channel activities have not been fully explored in Arabidopsis. Physiological and molecular techniques were employed to dissect the interaction of nitrogen and potassium nutrition in regulating stomatal opening, CO2 assimilation and ion channel activity. These data, gene expression and ABA signalling transduction were compared in wild-type Columbia-0 (Col-0) and the nitrate reductase mutant nia1nia2. Growth and K(+) nutrition were impaired along with stomatal behaviour, membrane transport, and expression of genes associated with ABA signalling in the nia1nia2 mutant. ABA-inhibited K(+) in current and ABA-enhanced slow anion current were absent in nia1nia2. Exogenous NO restored regulation of these channels for complete stomatal closure in nia1nia2. While NO is an important signalling component in ABA-induced stomatal closure in Arabidopsis, our findings demonstrate a more complex interaction associating potassium nutrition and nitrogen metabolism in the nia1nia2 mutant that affects stomatal function. PMID:26508536

  13. Genetics Home Reference: 5-alpha reductase deficiency

    MedlinePlus

    ... HYPOSPADIAS Sources for This Page Bahceci M, Ersay AR, Tuzcu A, Hiort O, Richter-Unruh A, Gokalp D. A novel missense mutation of 5-alpha reductase type 2 gene (SRD5A2) leads to severe male pseudohermaphroditism in a ...

  14. Controversial roles of methylenetetrahydrofolate reductase polymorphisms and folate in breast cancer disease.

    PubMed

    Bravatà, Valentina

    2015-02-01

    Breast cancer (BC) represents a highly heterogeneous tumour at both the clinical and molecular levels. Single-nucleotide polymorphisms (SNPs) of the folate-metabolising enzyme methylenetetrahydrofolate-reductase (MTHFR) may modify the association between folate intake and BC and influence plasma folate concentration. The role of folate in BC is equivocal, association studies between the common MTHFR SNPs C677T and A1298C and BC risk are controversial. In this study, I have reviewed observed associations between folate intake, as well as its blood levels, and BC. The purpose of this review is to analyse the role of folate and the two SNPs associated with reduced enzyme activity in BC. I explored the most relevant and updated work that emphasises positive and negative associations among these variables. My findings indicate that no definitive conclusions can be drawn from the studies on this topic. However, this manuscript highlights variables that could be useful to explore in further association analyses. PMID:25318348

  15. Association of Blood Lead Levels with Methylenetetrahydrofolate Reductase Polymorphisms among Chinese Pregnant Women in Wuhan City

    PubMed Central

    Shen, Wei; Zhang, Bin; Liu, Shuyun; Wu, Hongling; Gu, Xue; Qin, Lingzhi; Tian, Ping; Zeng, Yun; Ye, Linxiang; Ni, Zemin; Wang, Qi

    2015-01-01

    Background Pregnancy is an important stimulus of bone lead release. Elevated blood lead levels (BLLs) may cause adverse pregnancy outcomes for mothers and harmful lead effects on fetuses. However, the reports about maternal BLL changes during pregnancy are conflicting to some extent. This article is to explore the variations in BLLs among pregnant women. The relationships of BLLs with methylenetetrahydrofolate reductase (MTHFR) gene C677T, A1298C, and G1793A polymorphisms, which are associated with bone resorption, were also studied. A total of 973 women, including 234, 249, and 248 women in their first, second, and third trimesters, respectively, and 242 non-pregnant women, were recruited at the Wuhan Women and Children Medical Health Center. Methods BLLs were determined using a graphite furnace atomic absorption spectrometer. Single-nucleotide polymorphisms of MTHFR were identified with the TaqMan probe method. Results The geometric mean (geometric standard deviation) of BLLs was 16.2 (1.78) μg/L for all participants. All the studied MTHFR alleles were in Hardy-Weinberg equilibrium. Multiple-linear regression analysis revealed the following results. Among the pregnant women, those that carried MTHFR 677CC (i.e. wild-genotype homozygote) and 1298CC (i.e. mutant-genotype homozygote) exhibited higher BLLs than those that carried 677CT/TT (standardized β = 0.074, P = 0.042) and 1298AC/AA (standardized β = 0.077, P = 0.035) when other covariates (e.g., age, no. of children, education and income, etc.) were adjusted. The BLLs of pregnant women consistently decreased during the pregnancy and these levels positively correlated with BMI (standard β = 0.086–0.096, P<0.05). Conclusions The 1298CC mutant-type homozygote in the MTHFR gene is a risk factor for high BLLs among low-level environmental lead-exposed Chinese pregnant women, whose BLLs consistently decreased during gestation. PMID:25723397

  16. Incidence Assessment of MTHFR C677T and A1298C Polymorphisms in Iranian Non-syndromic Cleft Lip and/or Palate Patients.

    PubMed

    Ebadifar, Asghar; Ameli, Nazila; Khorramkhorshid, Hamid Reza; Salehi Zeinabadi4, Mehdi; Kamali, Kourosh; Khoshbakht, Tayyebeh

    2015-01-01

    Background and aims. The aim of the present study is to determine the incidence of MTHFR C677 T and A1298C muta-tions in Iranian patients with cleft lip and/or cleft palate. Materials and methods. We screened 61 Iranian patients with cleft lip and/or cleft palate for mutations in the two alleles of MTHFR gene associated with cleft lip and/or palate: A1298C and C677T, using Polymerase Chain Reaction following by RFLP. Results. The 677T and 1298C homozygote genotypes showed a frequency of 36.1% and 11.4%, respectively. Combined genotype frequencies in newborns having oral clefts showed that the highest genotype was 677TT/1298AA (22.9%) and 677TT/1298CC genotypes were not observed. Conclusion. The results showed that 65.6% of all patients had at least one T mutant allele in C677T and 58.9% C mutant allele for A1298C. According to the frequencies of homozygosity of mutant alleles, it could be said that MTHFR genotype of 677TT shows a greater role in having oral clefts. PMID:26236436

  17. Incidence Assessment of MTHFR C677T and A1298C Polymorphisms in Iranian Non-syndromic Cleft Lip and/or Palate Patients

    PubMed Central

    Ebadifar, Asghar; Ameli, Nazila; Khorramkhorshid, Hamid Reza; Salehi Zeinabadi4, Mehdi; Kamali, Kourosh; Khoshbakht, Tayyebeh

    2015-01-01

    Background and aims. The aim of the present study is to determine the incidence of MTHFR C677 T and A1298C muta-tions in Iranian patients with cleft lip and/or cleft palate. Materials and methods. We screened 61 Iranian patients with cleft lip and/or cleft palate for mutations in the two alleles of MTHFR gene associated with cleft lip and/or palate: A1298C and C677T, using Polymerase Chain Reaction following by RFLP. Results. The 677T and 1298C homozygote genotypes showed a frequency of 36.1% and 11.4%, respectively. Combined genotype frequencies in newborns having oral clefts showed that the highest genotype was 677TT/1298AA (22.9%) and 677TT/1298CC genotypes were not observed. Conclusion. The results showed that 65.6% of all patients had at least one T mutant allele in C677T and 58.9% C mutant allele for A1298C. According to the frequencies of homozygosity of mutant alleles, it could be said that MTHFR genotype of 677TT shows a greater role in having oral clefts. PMID:26236436

  18. The association between MTHFR 677C>T genotype and folate status and genomic and gene-specific DNA methylation in the colon of individuals without colorectal neoplasia1234

    PubMed Central

    Hanks, Joanna; Ayed, Iyeman; Kukreja, Neil; Rogers, Chris; Harris, Jessica; Gheorghiu, Alina; Liu, Chee Ling; Emery, Peter

    2013-01-01

    Background: Decreased genomic and increased gene-specific DNA methylation predispose to colorectal cancer. Dietary folate intake and the methylenetetrahydrofolate reductase polymorphism (MTHFR 677C>T) may influence risk by modifying DNA methylation. Objective: We investigated the associations between MTHFR 677C>T genotype, folate status, and DNA methylation in the colon. Design: We conducted a cross-sectional study of 336 men and women (age 19–92 y) in the United Kingdom without colorectal neoplasia. We obtained blood samples for measurement of serum and red blood cell folate, plasma homocysteine, and MTHFR 677C>T genotype and colonic tissue biopsies for measurement of colonic tissue folate and DNA methylation (genomic- and gene-specific, estrogen receptor 1, ESR1; myoblast determination protein 1, MYOD1; insulin-like growth factor II, IGF2; tumor suppressor candidate 33, N33; adenomatous polyposis coli, APC; mut-L homolog 1, MLH1; and O6-methylguanine-DNA methyltransferase, MGMT) by liquid chromatography/electrospray ionization mass spectrometry and pyrosequencing, respectively. Results: Of the 336 subjects recruited, 185 (55%) carried the CC, 119 (35%) the CT, and 32 (10%) the TT alleles. No significant differences in systemic markers of folate status and colonic tissue folate between genotypes were found. The MTHFR TT genotype was not associated with genomic or gene-specific DNA methylation. Biomarkers of folate status were not associated with genomic DNA methylation. Relations between biomarkers of folate status and gene-specific methylation were inconsistent. However, low serum folate was associated with high MGMT methylation (P = 0.001). Conclusion: MTHFR 677C>T genotype and folate status were generally not associated with DNA methylation in the colon of a folate-replete population without neoplasia. This trial was registered at clinicaltrials.gov as ISRCTN43577261. PMID:24108782

  19. Heterotrimeric NADH-Oxidizing Methylenetetrahydrofolate Reductase from the Acetogenic Bacterium Acetobacterium woodii

    PubMed Central

    Bertsch, Johannes; Öppinger, Christian; Hess, Verena; Langer, Julian D.

    2015-01-01

    ABSTRACT The methylenetetrahydrofolate reductase (MTHFR) of acetogenic bacteria catalyzes the reduction of methylene-THF, which is highly exergonic with NADH as the reductant. Therefore, the enzyme was suggested to be involved in energy conservation by reducing ferredoxin via electron bifurcation, followed by Na+ translocation by the Rnf complex. The enzyme was purified from Acetobacterium woodii and shown to have an unprecedented subunit composition containing the three subunits RnfC2, MetF, and MetV. The stable complex contained 2 flavin mononucleotides (FMN), 23.5 ± 1.2 Fe and 24.5 ± 1.5 S, which fits well to the predicted six [4Fe4S] clusters in MetV and RnfC2. The enzyme catalyzed NADH:methylviologen and NADH:ferricyanide oxidoreductase activity but also methylene-tetrahydrofolate (THF) reduction with NADH as the reductant. The NADH:methylene-THF reductase activity was high (248 U/mg) and not stimulated by ferredoxin. Furthermore, reduction of ferredoxin, alone or in the presence of methylene-THF and NADH, was never observed. MetF or MetVF was not able to catalyze the methylene-THF-dependent oxidation of NADH, but MetVF could reduce methylene-THF using methyl viologen as the electron donor. The purified MTHFR complex did not catalyze the reverse reaction, the endergonic oxidation of methyl-THF with NAD+ as the acceptor, and this reaction could not be driven by reduced ferredoxin. However, addition of protein fractions made the oxidation of methyl-THF to methylene-THF coupled to NAD+ reduction possible. Our data demonstrate that the MTHFR of A. woodii catalyzes methylene-THF reduction according to the following reaction: NADH + methylene-THF → methyl-THF + NAD+. The differences in the subunit compositions of MTHFRs of bacteria are discussed in the light of their different functions. IMPORTANCE Energy conservation in the acetogenic bacterium Acetobacterium woodii involves ferredoxin reduction followed by a chemiosmotic mechanism involving Na+-translocating ferredoxin oxidation and a Na+-dependent F1Fo ATP synthase. All redox enzymes of the pathway have been characterized except the methylenetetrahydrofolate reductase (MTHFR). Here we report the purification of the MTHFR of A. woodii, which has an unprecedented heterotrimeric structure. The enzyme reduces methylene-THF with NADH. Ferredoxin did not stimulate the reaction; neither was it oxidized or reduced with NADH. Since the last enzyme with a potential role in energy metabolism of A. woodii has now been characterized, we can propose a quantitative bioenergetic scheme for acetogenesis from H2 plus CO2 in the model acetogen A. woodii. PMID:25733614

  20. Methylenetetrahydrofolate reductase genotype association with the risk of follicular lymphoma.

    PubMed

    Ismail, Said I; Ababneh, Nida A; Khader, Yousef; Abu-Khader, Ahmad A; Awidi, Abdullah

    2009-12-01

    The metabolism of folate is essential in DNA synthesis, and polymorphisms of genes involved in such metabolism have been implicated in many types of cancer. Among these, the methylene tetrahydrofolate reductase gene (MTHFR) encodes an enzyme that converts folate to a methyl donor used for DNA methylation. We studied the association between the different genotypes of the two most common MTHFR polymorphisms, C677T and A1298C, and the risk of follicular lymphoma (FL). For this purpose, 55 previously diagnosed FL patients and 170 normal control subjects were examined using polymerase chain reaction followed by restriction fragment length polymorphism. The frequency of the A1298C CC homozygous mutant genotype was significantly higher in patients with FL than in control subjects (OR = 3.51, 95% CI = 1.39-8.86, P = 0.008). No such association was found for the heterozygous A1298C AC genotype (OR = 1.08, 95% CI = 0.55-2.12, P = 0.83). On the other hand, no significant association was found for either the C677T CT heterozygous genotype (OR = 0.79, 95% CI = 0.42-1.51, P = 0.49) or the C677T TT homozygous mutant genotype (OR = 0.55, 95% CI = 0.12-2.65, P = 0.46). The present findings add to the very few reports suggesting a link between the A1298C CC homozygous MTHFR genotype and a higher risk of developing FL, and the first such in a Jordanian population. PMID:19963111

  1. MTHFR Gene C677T Polymorphism in Autism Spectrum Disorders.

    PubMed

    Sener, Elif Funda; Oztop, Didem Behice; Ozkul, Yusuf

    2014-01-01

    Aim. Autism is a subgroup of autism spectrum disorders, classified as a heterogeneous neurodevelopmental disorder and symptoms occur in the first three years of life. The etiology of autism is largely unknown, but it has been accepted that genetic and environmental factors may both be responsible for the disease. Recent studies have revealed that the genes involved in the folate/homocysteine pathway may be risk factors for autistic children. In particular, C677T polymorphism in the MTHFR gene as a possible risk factor for autism is still controversial. We aimed to investigate the possible effect of C677T polymorphism in a Turkish cohort. Methods. Autism patients were diagnosed by child psychiatrists according to DSM-IV and DSM-V criteria. A total of 98 children diagnosed as autistic and 70 age and sex-matched children who are nonautistic were tested for C677T polymorphism. This polymorphism was studied by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods. Results. MTHFR 677T-allele frequency was found to be higher in autistic children compared with nonautistic children (29% versus 24%), but it was not found statistically significant. Conclusions. We conclude that other MTHFR polymorphisms such as A1298C or other folate/homocysteine pathway genes may be studied to show their possible role in autism. PMID:25431675

  2. MTHFR Gene C677T Polymorphism in Autism Spectrum Disorders

    PubMed Central

    Oztop, Didem Behice; Ozkul, Yusuf

    2014-01-01

    Aim. Autism is a subgroup of autism spectrum disorders, classified as a heterogeneous neurodevelopmental disorder and symptoms occur in the first three years of life. The etiology of autism is largely unknown, but it has been accepted that genetic and environmental factors may both be responsible for the disease. Recent studies have revealed that the genes involved in the folate/homocysteine pathway may be risk factors for autistic children. In particular, C677T polymorphism in the MTHFR gene as a possible risk factor for autism is still controversial. We aimed to investigate the possible effect of C677T polymorphism in a Turkish cohort. Methods. Autism patients were diagnosed by child psychiatrists according to DSM-IV and DSM-V criteria. A total of 98 children diagnosed as autistic and 70 age and sex-matched children who are nonautistic were tested for C677T polymorphism. This polymorphism was studied by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods. Results. MTHFR 677T-allele frequency was found to be higher in autistic children compared with nonautistic children (29% versus 24%), but it was not found statistically significant. Conclusions. We conclude that other MTHFR polymorphisms such as A1298C or other folate/homocysteine pathway genes may be studied to show their possible role in autism. PMID:25431675

  3. Screening for C677T and A1298C MTHFR polymorphisms in patients with epilepsy and risk of hyperhomocysteinemia.

    PubMed

    Caccamo, D; Condello, S; Gorgone, G; Crisafulli, G; Belcastro, V; Gennaro, S; Striano, P; Pisani, F; Ientile, R

    2004-01-01

    Hyperhomocysteinemia can result from decreased methylenetetrahydrofolate reductase (MTHFR) enzyme activity, owing to genetic polymorphisms andor inadequate folate intake. This study was aimed at investigating the prevalence of C677T and A1298C MTHFR polymorphisms, and their impact on hyperhomocysteinemia in 95 epileptic patients and 98 controls. Double gradient-denaturing gradient gel electrophoresis screening revealed that the frequency of T677 polymorphic allele was similar between cases and controls (46.3% vs 42.3%), whereas that of C1298 allele was significantly higher in patients (30.5% vs 19.4%, p < 0.05). Significant differences between the two groups were also found for the frequencies of genotypes AA1298 (46.3% in cases vs 67.3% in controls, p < 0.01) and AC1298 (46.3% in cases vs 26.6% in controls, p < 0.01). Other genotype frequencies did not show any statistically significant differences. Haplotype frequencies significantly differed between the two groups. The CT677/AC1298 diplotype was significantly more frequent in epileptic patients than in controls (32.6% vs 18.4%, p < 0.05). Patients treated with enzyme-inducing antiepileptic drugs, having this diplotype and concomitant low folate concentration (i.e., < 3.4 nmol/L), exhibited plasma homocysteine levels significantly higher than normal values (27.1 +/- 2.44 micromol/L, p < 0.001). This increase, however, was lower than that observed in folate-deficient patients with diplotype TT677/AA1298 (41.3 +/- 3.41 micromol/L, p < 0.001). Indeed, these two diplotypes could be regarded as risk factors for hyperhomocysteinemia. Conversely, we found that the CC677/AA1298 diplotype was significantly more frequent in controls (p < 0.01), suggesting a protective role. Our study suggests that both C677T and A1298C MTHFR polymorphisms should be examined when assessing genetic risk factors of hyperhomocysteinemia in epilepsy. PMID:15970629

  4. Morphology and Progression in Primary Varicose Vein Disorder Due to 677C>T and 1298A>C Variants of MTHFR

    PubMed Central

    Wilmanns, Christoph; Cooper, Alexis; Wockner, Leesa; Katsandris, Sotirios; Glaser, Nadine; Meyer, Alexander; Bartsch, Oliver; Binder, Harald; Walter, Paul Karl; Zechner, Ulrich

    2015-01-01

    Background Clinical assessment and prognostic stratification of primary varicose veins have remained controversial and the molecular pathogenesis is unknown. Previous data have suggested a contribution of the MTHFR (methylenetetrahydrofolate reductase) polymorphism c.677C>T. Methods We collected blood and vein specimens from 159 consecutive patients undergoing varicose vein surgery, or autologous vein reconstruction for arterial occlusive disease as controls. We compared the frequencies of c.677C>T and another polymorphism of MTHFR, c.1298A>C, with morphology and types of complicated disease. Morphology was recorded as a trunk or perforator type and peripheral congestive complication was defined as chronic venous insufficiency (CEAP C36) associated with edema and skin manifestations. Findings Multivariate analysis of genotypes for c.677C>T and c.1298A>C indicated that c.677C>T was associated significantly with the trunk phenotype (43/53 patients, 81%, p<0.01), while c.1298A>C was associated significantly with the perforator phenotype (18/24 patients, 75%, p<0.01) of primary varicose veins. Accordingly, when both c.677C>T and c.1298A>C displayed a heterozygous genotype, the patients were more likely to present with both phenotypes. Additionally, c.1298A>C was found to be strongly linked to the congestive complication (34/51 patients, 67%, p<0.01). Interpretation Both polymorphisms of MTHFR may be involved in the morphological specification of primary varicose veins and contribute to the development of complicated disease. Funding None. PMID:26137554

  5. Association between C677T and A1298C polymorphisms of the MTHFR gene and risk of male infertility: a meta-analysis.

    PubMed

    Yang, Y; Luo, Y Y; Wu, S; Tang, Y D; Rao, X D; Xiong, L; Tan, M; Deng, M Z; Liu, H

    2016-01-01

    Published studies on the association between the C677T and A1298C polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) gene and male infertility risk are controversial. To obtain a more precise evaluation, we performed a meta-analysis based on published case-control studies. We conducted an electronic search of PubMed, EMBASE, the Cochrane Library, the Web of Science, and the China Knowledge Resource Integrated Database for papers on MTHFR gene C677T and A1298C polymorphisms and male infertility risk. Pooled odds ratios (ORs) with 95% confidence intervals (95%CIs) were used to assess the strength of association in homozygote, heterozygote, dominant, recessive, and additive models. Statistical heterogeneity, test of publication bias, and sensitivity analysis were carried out using the STATA software (Version 13.0). Overall, 21 studies of C677T (4505 cases and 4024 controls) and 13 studies of A1298C (2785 cases and 3094 controls) were included in this meta-analysis. For C677T, the homozygote comparison results were OR = 1.629, 95%CI (1.215- 2.184), and the recessive model results were OR = 1.462 (1.155- 1.850). For A1298C, the homozygote comparison results were OR = 1.289 (1.029-1.616), and the recessive model results were OR = 1.288 (1.034-1.604). In conclusion, the current meta-analysis showed that the MTHFR C677T polymorphism was associated with a significantly increased male infertility risk in the Asian and overall populations, but not in the Caucasian population, and there was a significant association between the A1298C polymorphism and male infertility risk in the Asian, Caucasian, and overall groups. PMID:27173242

  6. Effect of polymorphisms of the MTHFR and APOE genes on susceptibility to diabetes and severity of diabetic retinopathy in Brazilian patients.

    PubMed

    Errera, F I V; Silva, M E R; Yeh, E; Maranduba, C M C; Folco, B; Takahashi, W; Pereira, A C; Krieger, J E; Passos-Bueno, M R

    2006-07-01

    Diabetes mellitus (DM) is a highly prevalent complex genetic disorder. There has been a worldwide effort in the identification of susceptibility genes for DM and its complications, and the 5-10-methylenetetrahydrofolate reductase (MTHFR) and apolipoprotein-E (APOE) genes have been considered good candidate susceptibility genes to this condition. The objectives of the present study were to determine if the 677T MTHFR and epsilon2/epsilon3/epsilon4 APOE alleles are risk factors for DM and for severity of diabetic retinopathy (DR). A total of 248 individuals were studied: 107 healthy individuals and 141 diabetic patients (46 with type 1 diabetes and 95 with type 2 diabetes), who also had DR (81 with non-proliferative DR and 60 with proliferative DR). The polymorphisms were analyzed by PCR followed by digestion with restriction enzyme or the single-nucleotide primer extension method. No evidence of association between the 677TT genotype of MTHFR gene and DM [cases: TT = 10/95 (10.6%); controls: TT = 14/107 (13%)] or with severity of DR was observed [cases: TT = 5/60 (8.5%); controls: TT = 9/81 (11.1%); P > 0.05]. We also did not find evidence of an association between APOE alleles and proliferative DR (epsilon2, epsilon3 and epsilon4 in cases: 9, 76, and 15%, and in controls: 5, 88, and 12%, respectively) but the carriers of epsilon2 allele were more frequent among patients with type 2 DM and DR than in controls [cases: 15/95 (15.8%); controls: 7/107 (6.5%); P < 0.05]. Therefore, our results suggest that the epsilon2 allele/APOE might be a risk factor for diabetes in the Brazilian population. PMID:16862278

  7. Methylenetetrahydrofolate reductase gene C677T, A1298C polymorphisms and pre-eclampsia risk: a meta-analysis.

    PubMed

    Li, Xing; Luo, Ya L; Zhang, Qiong H; Mao, Chen; Wang, Xi W; Liu, Shan; Chen, Qing

    2014-08-01

    To determine whether methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms are associated with pre-eclampsia susceptibility. Literature searches of the Pubmed, Embase, BIOSIS Previews and Web of Science were conducted to identify all eligible articles up to January 18th, 2013. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) of five genetic models were calculated by fixed-effects or random-effects model. Publication bias, subgroup analysis, meta-regression and sensitivity analysis were also performed. A number of 49 studies including 51 samples consisted of 18,009 subjects (6,238 patients and 11,771 controls) were finally included. MTHFR C677T allele (TT or CT) carriers were 1.12 times more likely to develop pre-eclampsia (95% CI 1.04-1.21) compared with 677CC homozygous individuals. Similar results were obtained under other genetic models. Restricted to severe pre-eclampsia, there was an increased risk for 677TT homozygotes compared with 677CC homozygotes (OR 1.43; 95% CI 1.12-1.83). Subgroup analysis revealed a significant positive association between the C677T polymorphism (TT or CT) and pre-eclampsia in Asians (OR 1.41; 95% CI 1.11-1.79) and white population (OR 1.14; 95% CI 1.03-1.25). Meta-regression showed that study population, blinded genotyping, matching of cases and controls were not substantial sources of heterogeneity. For the MTHFR A1298C, ORs for all genetic models yielded a null association. This meta-analysis suggests that the MTHFR 677T allele might be associated with increased pre-eclampsia risk in Asian and white ethnicity and the subgroup of severe pre-eclampsia, while no association is observed between the MTHFR A1298C polymorphism and pre-eclampsia. PMID:24898880

  8. Methylenetetrahydrofolate Reductase A1298C Polymorphism and Breast Cancer Risk: A Meta-analysis of 33 Studies.

    PubMed

    Rai, V

    2014-11-01

    Methylenetetrahydrofolate reductase (MTHFR) enzyme is essential for DNA synthesis and DNA methylation, and its gene polymorphisms have been implicated as risk factors for birth defects, neurological disorders, and different types of cancers. Several studies have investigated the association between the MTHFR A1298C polymorphism and breast cancer (BC) risk, but the results were inconclusive. To assess the risk associated with MTHFR A1298C polymorphism, a comprehensive meta-analysis was performed. PubMed, Google Scholar, Elsevier and Springer Link databases were searched for case-control studies relating the association between MTHFR A1298C polymorphism and BC risk and estimated summary odds ratios (ORs) with confidence intervals (CIs) for assessment. Up to January 2014, 33 case-control studies involving 15,919 BC patients and 19,700 controls were included in the present meta-analysis. The results showed that the A1298C polymorphism was not associated with BC risk in all the five genetic models (C vs. A allele (allele contrast): OR = 0.99, 95% confidence interval (CI): 0.93-1.05; AC versus AA (heterozygote/codominant): OR = 0.97, 95% CI: 0.89-1.04; CC versus AA (homozygote): OR = 0.99, 95% CI: 0.91-1.06; CC + AC versus AA (dominant model): OR = 0.97, 95% CI: 0.90-1.05; and CC versus AC + AA (recessive model): OR = 0.99, 95% CI: 0.91-1.07). The present meta-analysis did not support any association between the MTHFR A1298C polymorphism and BC risk. PMID:25506474

  9. Structure of an integral membrane sterol reductase from Methylomicrobium alcaliphilum

    PubMed Central

    Li, Xiaochun; Roberti, Rita; Blobel, Günter

    2014-01-01

    Sterols are essential biological molecules in the majority of life forms. Sterol reductases1 including Delta-14 sterol reductase (C14SR), 7-dehydrocholesterol reductase (DHCR7) and 24-dehydrocholesterol reductase (DHCR24) reduce specific carbon-carbon double bonds of the sterol moiety using a reducing cofactor during sterol biosynthesis. Lamin B Receptor2 (LBR), an integral inner nuclear membrane protein, also contains a functional C14SR domain. Here we report the crystal structure of a Delta-14 sterol reductase (maSR1) from the methanotrophic bacterium Methylomicrobium alcaliphilum 20Z, a homolog of human C14SR, LBR, and DHCR7, with the cofactor NADPH. The enzyme contains 10 transmembrane segments (TM). Its catalytic domain comprises the C-terminal half (containing TM6-10) and envelops two interconnected pockets, one of which faces the cytoplasm and houses NADPH, while the other one is accessible from the lipid bilayer. Comparison with a soluble steroid 5β-reductase structure3 suggests that the reducing end of NADPH meets the sterol substrate at the juncture of the two pockets. A sterol reductase activity assay proves maSR1 can reduce the double bond of a cholesterol biosynthetic intermediate demonstrating functional conservation to human C14SR. Therefore, our structure as a prototype of integral membrane sterol reductases provides molecular insight into mutations in DHCR7 and LBR for inborn human diseases. PMID:25307054

  10. The protective effect of methylenetetrahydrofolate reductase C677T polymorphism against prostate cancer risk: Evidence from 23 case-control studies.

    PubMed

    Guo, Shanqi; Jiang, Xingkang; Chen, Xiaobo; Chen, Liang; Li, Xiaojiang; Jia, Yingjie

    2015-07-01

    Genetic polymorphisms of methylenetetrahydrofolate reductase (MTHFR) were considered to have some influence on both folate metabolism and cancer risk. Previous studies on the relation between MTHFR C677T polymorphism and prostate cancer (PCa) risk remained controversial. To derive a more precise estimation of the relationship, we carried out an update comprehensive meta-analysis to assess the associations of the MTHFR C677T polymorphism with the susceptibility of PCa. Twenty-three trials with a total of 24,024 participants on the MTHFR C677T polymorphism that met inclusion criteria were analyzed in the current study. Overall, no statistical relationship was found with any MTHFR C677T genetic model associated with susceptibility to PCa (TT versus CC, OR=0.83, 95% CI 0.68-1.02, P=0.07; CT versus CC, OR=0.95, 95% CI 0.85-1.07, P=0.43; Dominant, OR=0.93, 95% CI 0.83-1.03, P=0.17; Recessive, OR=0.84, 95% CI 0.70-1.02, P=0.09.). Nevertheless, subgroup analysis found a reduced PCa risk associated with polymorphism in Asian population (TT versus CC, CT versus CC, dominant and recessive model). Moreover, the protective effect of polymorphism against PCa risk was also shown upon hospital-based studies (TT versus CC, and recessive model). When benign prostate hyperplasia was chosen as controls, both TT versus CC and recessive model showed significant difference. In addition, the protective effect of homozygote TT against high aggressive PCa was proved to have significant difference. Taken together, the existing evidence indicates the homozygote TT of MTHFR C677T should be viewed as a protective factor against PCa risk for clinical practice with the consideration of different gene background, study design as well as specific controls. PMID:25841988

  11. Atherosclerosis in male patients with ankylosing spondylitis: the relation with methylenetetrahydrofolate reductase (C677T) gene polymorphism and plasma homocysteine levels.

    PubMed

    Geçene, Muharrem; Tuncay, Figen; Borman, Pınar; Yücel, Dogan; Senes, Mehmet; Yılmaz, Behice Kaniye

    2013-06-01

    The aim of this study was to determine the intima-media thickness (IMT) in carotid arteries and to assess the relation of these values with plasma homocysteine (pHcy) levels and methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism in patients with Ankylosing spondylitis (AS). Serum lipids, vitamin B12, folic acid, pHcy and acute phase protein levels were measured in all cases. MTHFR C677T gene polymorphisms were determined, and IMT of main carotid artery were evaluated ultrasonographically in all subjects. Bath Ankylosing Spondylitis Disease Activity Index, Ankylosing Spondylitis Disease Activity score and Bath Ankylosing Spondylitis Metrology Index were used to assess disease activity and spinal mobility. Fifty AS patients (mean age of 36.6 ± 4.79 years) and 50 control subjects (36.34 ± 4.72 years) were included in the study. Plasma homocysteine levels of AS patients and control group were also similar (14.26 ± 9.96 vs. 11.81 ± 5.53 μmol/L). Hyperhomocysteinemia was present in 11 subjects in patient group (22.0 %), while it was seen in 5 subjects in the control group (10.0 %). The MTHFR C677T genotype distribution was as follows: CC 31 (62 %), CT 14 (28 %), TT 5 (10 %) in AS patients. The mean carotid IMT values were also found to be similar between the groups. The most important factor influencing pHcy level was found as MTHFR 677TT genotype. We indicated no difference of atherosclerosis indices revealed by IMT values and pHcy levels AS patients and control subjects. But an association between MTHFR 677 gene polymorphism and pHcy levels was concluded, which may suggest that MTHFR 677 TT polymorphism may be a potential prognostic factor for cardiovascular disease in patients with AS. PMID:23247802

  12. [Association between methylene-tetrahydrofolate reductase gene polymorphisms and chronic myeloid leukemia].

    PubMed

    Dorgham, Samia; Aberkane, Meriem; Boughrara, Wefa; Antar Soltan, Badra; Mehalhal, Nemra; Touhami, Hadj; Sidimansour, Noureddine; Merad Boudia, Nadia; Louhibi, Lotfi; Boudjema, Abdallah

    2014-09-01

    Methylene-tetrahydrofolate reductase (MTHFR) is a key enzyme of folate metabolism. Few studies were reported about its relationship with chronic myeloid leukemia (CML). We conducted a case-control study analyzing the prevalence of the polymorphisms MTHFR C677T and MTHFR A1298C in Algerians CML patients. Using TaqMan(®) allelic discrimination assay, we investigate MTHFR C677T and A1298C polymorphism distribution in 90 cases of CML and 100 healthy subjects. The frequencies of 677T alleles and genotypes 677TT and 677CT were significantly higher in cases than in control (P = 1E-6; OR = 6.77 [4.22-10.86]) and (P = 1E-6; OR = 10.38 [4.56-23.6]) respectively. Also, the frequencies of 1298C alleles and genotypes 1298CC and 1298AC were higher in cases (P = 9 E-6; OR = 2.65 [1.71-4.10]) and (P = 0.008; OR = 2.22 [1.21-4.06]) respectively. We report also the higher significance of the haplotype 677T/1298A and 677T/1298C in cases (P = 0.007; OR = 2.57 [1.26-5.24]) and (P = 5 E-6, OR = 6.91 [2.7646-17.2899]) respectively. Our results demonstrate that 677T and 1298C alleles are both associated with an increased risk of CML in Algeria. PMID:25036376

  13. Methylenetetrahydrofolate reductase C677T and A1298C polymorphisms and gastric cancer susceptibility

    PubMed Central

    Xia, Lei-Zhou; Liu, Yi; Xu, Xiao-Zhou; Jiang, Peng-Cheng; Ma, Gui; Bu, Xue-Feng; Zhang, Yong-Jun; Yu, Feng; Xu, Ke-Sen; Li, Hua

    2014-01-01

    AIM: To identify the association between methylenetetrahydrofolate reductase (MTHFR) polymorphisms and gastric cancer (GC) susceptibility. METHODS: Systematic searches were performed on the electronic databases PubMed, ISI, Web of knowledge, CNKI and Wanfang, as well as manual searching of the references of the identified articles. A total of 26 papers were included in this meta-analysis. Overall and subgroup analyses were performed. Odds ratio (OR) and 95%CI were used to evaluate the associations between MTHFR polymorphisms and GC risk. The I2 statistics were used to evaluate between-study heterogeneity. Sensitivity analysis was also performed. RESULTS: Increased risk was found for the MTHFR C677T polymorphism under four genetic models (TT + CT vs CC: OR = 1.23, P = 0.002; T vs C: OR = 1.15, P = 0.001; TT vs CC: OR = 1.37, P = 0.0005; TT vs CT + CC: OR = 1.17, P = 0.0008). Subgroup analysis by ethnicity suggested that C677T polymorphism conferred a risk of GC in eastern but not in western populations. Stratification by tumor site showed an association between the C677T polymorphism and gastric cardia cancer and non-cardia GC in the worldwide population and in eastern populations. Regardless of comparisons with controls or diffuse-type GC, a positive association was found for the C677T polymorphism and an increased risk of intestinal-type GC in the whole population and in western populations. With regard to the A1298C polymorphism, we found that genotype CC was significantly decreased and conferred protection against GC in eastern populations (CC vs AA: OR = 0.44, P = 0.03; CC vs AC + AA: OR = 0.46, P = 0.04). CONCLUSION: MTHFR C677T polymorphism is a risk factor for GC, and the A1298C polymorphism may be a protective factor against GC in eastern populations. PMID:25170232

  14. A novel lateral flow assay based on GoldMag nanoparticles and its clinical applications for genotyping of MTHFR C677T polymorphisms.

    PubMed

    Hui, Wenli; Zhang, Sinong; Zhang, Chao; Wan, Yinsheng; Zhu, Juanli; Zhao, Gang; Wu, Songdi; Xi, Dujuan; Zhang, Qinlu; Li, Ningning; Cui, Yali

    2016-02-14

    Current techniques for single nucleotide polymorphism (SNP) detection require tedious experimental procedures and expensive and sophisticated instruments. In this study, a visual genotyping method has been successfully established via combining ARMS-PCR with gold magnetic nanoparticle (GoldMag)-based lateral flow assay (LFA) and applied to the genotyping of methylenetetrahydrofolate reductase (MTHFR) C677T. C677T substitution of the gene MTHFR leads to an increased risk of diseases. The genotyping result is easily achievable by visual observation within 5 minutes after loading of the PCR products onto the LFA device. The system is able to accurately assess a broad detection range of initial starting genomic DNA amounts from 5 ng to 1200 ng per test sample. The limit of detection reaches 5 ng. Furthermore, our PCR-LFA system was applied to clinical trials for screening 1721 individuals for the C677T genotypes. The concordance rate of the genotyping results detected by PCR-LFA was up to 99.6% when compared with the sequencing results. Collectively, our PCR-LFA has been proven to be rapid, accurate, sensitive, and inexpensive. This new method is highly applicable for C677T SNP screening in laboratories and clinical practices. More promisingly, it could also be extended to the detection of SNPs of other genes. PMID:26804455

  15. A novel lateral flow assay based on GoldMag nanoparticles and its clinical applications for genotyping of MTHFR C677T polymorphisms

    NASA Astrophysics Data System (ADS)

    Hui, Wenli; Zhang, Sinong; Zhang, Chao; Wan, Yinsheng; Zhu, Juanli; Zhao, Gang; Wu, Songdi; Xi, Dujuan; Zhang, Qinlu; Li, Ningning; Cui, Yali

    2016-02-01

    Current techniques for single nucleotide polymorphism (SNP) detection require tedious experimental procedures and expensive and sophisticated instruments. In this study, a visual genotyping method has been successfully established via combining ARMS-PCR with gold magnetic nanoparticle (GoldMag)-based lateral flow assay (LFA) and applied to the genotyping of methylenetetrahydrofolate reductase (MTHFR) C677T. C677T substitution of the gene MTHFR leads to an increased risk of diseases. The genotyping result is easily achievable by visual observation within 5 minutes after loading of the PCR products onto the LFA device. The system is able to accurately assess a broad detection range of initial starting genomic DNA amounts from 5 ng to 1200 ng per test sample. The limit of detection reaches 5 ng. Furthermore, our PCR-LFA system was applied to clinical trials for screening 1721 individuals for the C677T genotypes. The concordance rate of the genotyping results detected by PCR-LFA was up to 99.6% when compared with the sequencing results. Collectively, our PCR-LFA has been proven to be rapid, accurate, sensitive, and inexpensive. This new method is highly applicable for C677T SNP screening in laboratories and clinical practices. More promisingly, it could also be extended to the detection of SNPs of other genes.

  16. Quinone Reductase 2 Is a Catechol Quinone Reductase

    SciTech Connect

    Fu, Yue; Buryanovskyy, Leonid; Zhang, Zhongtao

    2008-09-05

    The functions of quinone reductase 2 have eluded researchers for decades even though a genetic polymorphism is associated with various neurological disorders. Employing enzymatic studies using adrenochrome as a substrate, we show that quinone reductase 2 is specific for the reduction of adrenochrome, whereas quinone reductase 1 shows no activity. We also solved the crystal structure of quinone reductase 2 in complexes with dopamine and adrenochrome, two compounds that are structurally related to catecholamine quinones. Detailed structural analyses delineate the mechanism of quinone reductase 2 specificity toward catechol quinones in comparison with quinone reductase 1; a side-chain rotational difference between quinone reductase 1 and quinone reductase 2 of a single residue, phenylalanine 106, determines the specificity of enzymatic activities. These results infer functional differences between two homologous enzymes and indicate that quinone reductase 2 could play important roles in the regulation of catecholamine oxidation processes that may be involved in the etiology of Parkinson disease.

  17. Normal Weight Obese syndrome: role of single nucleotide polymorphism of IL-1 5Ralpha and MTHFR 677C-->T genes in the relationship between body composition and resting metabolic rate.

    PubMed

    Di Renzo, L; Bigioni, M; Bottini, F G; Del Gobbo, V; Premrov, M G; Cianci, R; De Lorenzo, A

    2006-01-01

    We have identified a subset of metabolically obese, but normal weight individuals, with potentially increased risks of developing the metabolic syndrome, despite their normal body mass index. We determined the relationship among body fat distribution, resting metabolic rate (RMR), total body water amount (%TBW), selected gene polymorphism on interleukin-15 receptor-alpha (IL-15Ralpha) and methylenetetrahydrofolate reductase 677C-->T (MTHFR 677C-->T), to distinguish normal weight obese (NWO) from nonobese with a normal metabolic profile and obese individuals. We analysed anthropometric variables, body composition by Dual energy X-ray Absorptiometry (DXA), RMR by indirect calorimetry, %TBW by bioimpedence analysis (BIA), MTHFR 677C-->T and IL-15Ralpha genotypes of 128 clinically healthy Caucasian individuals. We compared a group of female, defined as NWO and characterised by a BMI < or = 25 kg/m(2) and FM > or = 30% with groups of others female, and males, represented by nonobese with a BMI < or = 25 kg/m(2) and FM < or = 30%, and preobese-obese individuals with BMI > or = 25 kg/m(2) and %FM > or = 30%; none of the males was classified as NWO. Significant correlations were found among body fat mass distribution, metabolic variables, percentage of total body water distribution and selected genetic variations. The variables that contributed significantly to the separation of classes were body tissue (Tissue), %TBW, RMR, the volumes of both oxygen (VO2) and carbon dioxide (VCO2). The distribution of MTHFR 677C-->T and IL-15 genotypes was significantly different between classes. Our data highlight that NWO individuals showed a significant relationship between the decrease in the basal metabolism (RMR), body fat mass increasing and total water amount. Possession of wild type homozygotes genotypes regarding IL-15Ralpha cytokine and 677C-->T MTHFR enzyme characterised NWO individuals. PMID:17121316

  18. Association between methionine synthase reductase A66G polymorphism and primary infertility in Chinese males.

    PubMed

    Li, X Y; Ye, J Z; Ding, X P; Zhang, X H; Ma, T J; Zhong, R; Ren, H Y

    2015-01-01

    We examined the association between the methionine synthase reductase (MTRR A66G), methylenetetrahydrofolate reductase (MTHFR C677T and A1298C), and methionine synthase (MS A2756G) genotypes and non-obstructive male infertility in a Chinese population. This case-control study included 162 infertile Chinese patients with azoospermia (N = 100) or oligoasthenozoospermia (N = 62) and 120 fertile men as controls. The polymorphisms MTRR A66G, MTHFR C677T, A1298C, and MS A2756G were identified by direct DNA sequencing and the results were statistically analyzed. We found no association between the incidence of any of these variants in azoospermia patients and control populations. The frequency of the MTRR66 polymorphic genotypes (AG, AG+GG) was significantly higher in the oligoasthenozoospermia group compared to the controls (P = 0.013, 0.012). Our findings revealed an association between the single-nucleotide polymorphism A66G in the MTRR gene and male infertility, particularly in oligoasthenozoospermia males, suggesting that this polymorphism is a genetic risk factor for male infertility in Chinese men. PMID:25966116

  19. Association between Maternal MTHFR Polymorphisms and Nonsyndromic Cleft Lip with or without Cleft Palate in Offspring, A Meta-Analysis Based on 15 Case-Control Studies

    PubMed Central

    Pan, Xinjuan; Wang, Ping; Yin, Xinjuan; Liu, Xiaozhuan; Li, Di; Li, Xing; Wang, Yongchao; Li, Hongle; Yu, Zengli

    2015-01-01

    Background The methylenetetrahydrofolate reductase (MTHFR) is thought to be involved in the development of nonsyndromic cleft lip with or without cleft palate (NSCL/P). However, conflicting results have been obtained when evaluating the association between maternal MTHFR C677T and A1298C polymorphisms and the risk of NSCL/P. In light of this gap, a meta-analysis of all eligible case-control studies was conducted in the present study. Materials and Methods A total of 15 case-control studies were ultimately identified after a comprehensive literature search and Hardy-Weinberg equilibrium (HWE) examination. Cochranes Q test and index of heterogeneity (I2) indicated no obvious heterogeneity among studies. Results Fixed or random-effects models were used to calculate the pooled odds ratios (ORs). The results showed that the TT genotype in mothers increased the likelihood of having NSCL/P offspring 1.25 times (95% CI: 1.047-1.494) more than the CC homozygotes. Meanwhile, maternal TT genotype increased the risk of producing NSCL/P offspring in recessive model (OR=1.325, 95% CI: 1.124-1.562). However, the CT heterozygote and the CT+TT dominant models had no association with NSCL/P offspring compared with the CC wild-type homozygote model. Subgroup analyses based on ethnicity indicated that maternal TT genotype increased the likelihood of having NSCL/P offspring in Whites (OR=1.308, 95% CI: 1.059-1.617) and Asians (OR=1.726, 95% CI: 1.090-2.733) in recessive model. Also, subgroup analyses based on source of control showed that mothers with the 677TT genotype had a significantly increased susceptibility of having NSCL/P children in hospital based population (HB) when compared with CC homozygotes (OR=1.248, 95% CI: 1.024-1.520) and un- der the recessive model (OR=1.324, 95% CI: 1.104-1.588). Furthermore, maternal A1298C polymorphism had no significant association with producing NSCL/P offspring (dominant model OR=0.952, 95% CI: 0.816-1.111, recessive model OR=0.766, 95% CI: 0.567-1.036). Conclusion MTHFR C677T polymorphism is associated with the risk of generating NSCL/P offspring, and being a 677TT homozygote is a risk factor. MTHFR A1298C polymorphism was not associated with generating NSCL/P offspring. However, further work should be performed to confirm these findings. PMID:25780529

  20. Lack of association between MTHFR Ala222Val and Glu429Ala polymorphisms and bladder cancer risk: A meta-analysis of case-control studies

    PubMed Central

    SHI, RONG; ZHAO, ZHEN; ZHOU, HUI; ZHOU, JUEYU; TAN, WANLONG

    2014-01-01

    Bladder cancer is a commom malignancy in the urinary tract that is influenced by genetic and environmental factors. The role of functional polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene with bladder cancer risk remains to be determined. This meta-analysis was performed to derive a more precise estimation of MTHFR Ala222Val and Glu429Ala polymorphisms and bladder cancer risk. Data were collected with the last report up to September 2013. A total of 3,463 cases and 3,927 controls for Ala222Val, and 3,177 cases and 3,502 controls for Glu429Ala were analyzed. The pooled odds ratios (ORs) and 95% confidence interval (CI) were estimated for the association with bladder cancer risk. Overall, no significant associations of Ala222Val and Glu429Ala polymorphisms with bladder cancer risk were found (for Ala222Val: Val/Val vs. Ala/Ala: OR, 1.02; 95% CI: 0.80–1.29; Val/Ala vs. Ala/Ala: OR, 1.02; 95% CI: 0.92–1.12; dominant model: OR, 1.01; 95% CI: 0.87–1.17; recessive model: OR, 1.00; 95% CI: 0.87–1.15; and for Glu429Ala: Ala/Ala vs. Glu/Glu: OR, 1.11; 95% CI: 0.78–1.58; Ala/Glu vs. Glu/Glu: OR, 1.16; 95% CI: 0.95–1.40; dominant model: OR, 1.15; 95% CI: 0.94–1.41; recessive model: OR, 0.96; 95% CI: 0.79–1.15). In stratified analyses by ethnicity, significant associations were observed for Glu429Ala polymorphism in individuals of Middle Eastern descent (Ala/Glu vs. Glu/Glu: OR, 2.11; 95% CI: 1.26–3.53; dominant model: OR, 2.16; 95% CI: 1.16–4.01; recessive model: OR, 1.82; 95% CI: 1.11–3.01). This meta-analysis demonstrated that overall there was no association of MTHFR Ala222Val and Glu429Ala polymorphisms with bladder cancer risk. However, in the stratified analysis by ethnicity the MTHFR Glu429Ala polymorphism was significantly associated with increased bladder cancer risk in individuals of Middle Eastern descent. PMID:24748982

  1. Polymorphisms in the MTHFR gene influence embryo viability and the incidence of aneuploidy.

    PubMed

    Enciso, María; Sarasa, Jonás; Xanthopoulou, Leoni; Bristow, Sara; Bowles, Megan; Fragouli, Elpida; Delhanty, Joy; Wells, Dagan

    2016-05-01

    MTHFR is an important enzyme in the metabolism of folic acid and is crucial for reproductive function. Variation in the sequence of MTHFR has been implicated in subfertility, but definitive data are lacking. In the present study, a detailed analysis of two common MTHFR polymorphisms (c.677C>T and c.1298A>C) was performed. Additionally, for the first time, the frequencies of different MTHFR alleles were assessed in preimplantation embryos. Several striking discoveries were made. Firstly, results demonstrated that maternal MTHFR c.1298A>C genotype strongly influences the likelihood of a pregnancy occurring, with the 1298C allele being significantly overrepresented amongst women who have undergone several unsuccessful assisted reproductive treatments. Secondly, parental MTHFR genotypes were shown to affect the production of aneuploid embryos, indicating that MTHFR is one of the few known human genes with the capacity to modulate rates of chromosome abnormality. Thirdly, an unusual deviation from Hardy-Weinberg equilibrium was noted for the c.677C>T polymorphism in subfertile patients, especially those who had experienced recurrent failure of embryo implantation or miscarriage, potentially explained by a rare case of heterozygote disadvantage. Finally, a dramatic impact of the MTHFR 677T allele on the capacity of chromosomally normal embryos to implant is described. Not only do these findings raise a series of interesting biological questions, but they also argue that testing of MTHFR could be of great clinical value, identifying patients at high risk of implantation failure and revealing the most viable embryos during in vitro fertilisation (IVF) cycles. PMID:27068821

  2. Methylenetetrahydrofolate reductase gene germ-line C677T and A1298C SNPs are associated with colorectal cancer risk in the Turkish population.

    PubMed

    Ozen, Filiz; Sen, Metin; Ozdemir, Ozturk

    2014-01-01

    Colorectal cancer (CRC) is the third most common cause of death due to cancer in the worldwide and the incidence is also increasing in Turkey. Our present aim was to investigate any association between germ-line methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms and CRC risk in Turkey. A total of 86 CRC cases and 212 control individuals of the same ethnicity were included in the current study. Peripheral blood-DNA samples were used for genotyping by StripAssay technique, based on the reverse- hybridization principle and real-time PCR methods. Results were compared in Pearson Chi-square and multiple logistic regression models. The MTHFR 677TT (homozygous) genotype was found in 20.9% and the T allele frequency 4.2-fold increased in CRC when compared with the control group.The second SNP MTHFR 1298CC (homozygous) genotype was found in 14.0% and the C allele frequency 1.4-fold elevated in the CRC group. The current data suggest strong associations between both SNPs of germ-line MTHFR 677 C>T and 1298 A>C genotypes and CRC susceptibility in the Turkish population. Now the results need to be confirmed with a larger sample size. PMID:25292054

  3. Correlation between the 677C>T polymorphism in the methylene tetrahydrofolate reductase gene and serum homocysteine levels in coronary heart disease.

    PubMed

    Chen, Y Y; Wang, B N; Yu, X P

    2016-01-01

    The aim of the current study was to explore the correlation between serum homocysteine (HCY) levels and the methylene tetrahydrofolate reductase (MTHFR) gene 677C/T polymorphism and coronary heart disease (CHD). We consecutively enrolled 208 patients with CHD confirmed by CTA or coronary angiography from our hospital. An additional 200 healthy volunteers were enrolled as the control group. Serum HCY levels, MTHFR C677T genotype, and other related indicators were evaluated for the two groups. Compared to those in the control group, the serum HCY levels in the CHD patients were significantly higher (P < 0.05). The proportion of individuals with the heterozygous MTHFR CT genotype and homozygous mutant TT genotype among CHD patients was significantly higher than that in the control group (P < 0.05). In the acute coronary syndrome (ACS) subgroup, the proportion of those with the CT and TT genotypes was significantly higher than that of the stable CHD subgroup (P < 0.05). In summary, serum HCY levels were elevated in CHD patients, and the frequency of the CT and TT genotypes were also significantly increased, especially among the ACS subgroup. Taken together, this suggests that serum HCY levels and MTHFR C677T genotypes are correlated with CHD. PMID:27051002

  4. Breast cancer risk associated with gene expression and genotype polymorphisms of the folate-metabolizing MTHFR gene: a case-control study in a high altitude Ecuadorian mestizo population.

    PubMed

    López-Cortés, Andrés; Echeverría, Carolina; Oña-Cisneros, Fabián; Sánchez, María Eugenia; Herrera, Camilo; Cabrera-Andrade, Alejandro; Rosales, Felipe; Ortiz, Malena; Paz-Y-Miño, César

    2015-08-01

    Breast cancer (BC) is the leading cause of cancer-related death among women in 2014. Methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTR), and MTR reductase (MTRR) are enzymes that play an important role in folate metabolism. The single nucleotide polymorphisms, MTHFR C677T, A1298C, MTR A2756G, and MTRR A66G, alter plasmatic folate and homocysteine concentrations, causing problems during the repairment, synthesis, and methylation of the genetic material. Therefore, it is essential to know how BC risk is associated with histopathological and immunohistochemical characteristics, genotype polymorphisms, and gene expression in a high altitude Ecuadorian mestizo population. DNA was extracted from 195 healthy and 114 affected women. Genotypes were determined by restriction enzymes and genomic sequencing. mRNA was extracted from 26 glandular breast tissue samples, both from cancerous tissue and healthy tissue adjacent to the tumor. Relative gene expression was determined with the comparative Livak method (2(-ΔΔCT)). We found significant association between the rs1801133 (A222V) genotypes and an increased risk of BC development: C/T (odds ratio [OR] = 1.8; 95 % confidence interval [CI] = 1.1-3.2; P = 0.039), T/T (OR = 2.9; 95 % CI = 1.2-7.2; P = 0.025), and C/T + T/T (OR = 1.9; 95 % CI = 1.1-3.3; P = 0.019). Regarding relative gene expression, we found significant mRNA subexpression between the combined genotypes C/T + T/T (rs1801133) and triple negative breast cancer (TNBC) (P = 0.034). In brief, the MTHFR gene and its protein could act as potential predictive biomarkers of BC, especially TNBC among the high altitude Ecuadorian mestizo population. PMID:25801246

  5. Are MTHFR C677T and MTRR A66G Polymorphisms Associated with Overweight/Obesity Risk? From a Case-Control to a Meta-Analysis of 30,327 Subjects

    PubMed Central

    Fan, Shu-Jun; Yang, Bo-Yi; Zhi, Xue-Yuan; He, Miao; Wang, Da; Wang, Yan-Xun; Wang, Yi-Nuo; Wei, Jian; Zheng, Quan-Mei; Sun, Gui-Fan

    2015-01-01

    Several studies have examined the associations of methylenetetrahydrofolate reductase (MTHFR) C677T and methionine synthase reductase (MTRR) A66G polymorphisms with being overweight/obesity. However, the results are still controversial. We therefore conducted a case-control study (517 cases and 741 controls) in a Chinese Han population and then performed a meta-analysis by combining previous studies (5431 cases and 24,896 controls). In our case-control study, the MTHFR C677T polymorphism was not significantly associated with being overweight/obesity when examining homozygous codominant, heterozygous codominant, dominant, recessive and allelic genetic models. The following meta-analysis confirmed our case-control results. Heterogeneity was minimal in the overall analysis, and sensitivity analyses and publication bias tests indicated that the meta-analytic results were reliable. Similarly, both the case-control study and meta-analysis found no significant association between the MTRR A66G polymorphism and being overweight/obesity. However, sensitivity analyses showed that the associations between the MTRR A66G polymorphism and being overweight/obesity became significant in the dominant, heterozygous codominant and allelic models after excluding our case-control study. The results from our case-control study and meta-analysis suggest that both of the two polymorphisms are not associated with being overweight/obesity. Further large-scale population-based studies, especially for the MTRR A66G polymorphism, are still needed to confirm or refute our findings. PMID:26016497

  6. Methylenetetrahydrofolate Reductase C677T Polymorphism and Type 2 Diabetes Mellitus in Chinese Population: A Meta-Analysis of 29 Case-Control Studies

    PubMed Central

    Zhu, Bo; Wu, Xiaomei; Zhi, Xueyuan; Liu, Lei; Zheng, Quanmei; Sun, Guifan

    2014-01-01

    Background Methylenetetrahydrofolate reductase (MTHFR), a key enzyme in folate metabolism, had significant effects on the homocysteine levels. The common functional MTHFR C677T polymorphism had been extensively researched. Several studies had evaluated the relationship between MTHFR C677T polymorphism and type 2 diabetes mellitus (T2DM), but the results were still controversial in the Chinese Han population. This meta-analysis was conducted to evaluate the relationship between MTHFR C677T polymorphism and T2DM in the Chinese Han population. Methods We searched the relevant studies in multiple electronic databases, which published up to December 2013. We reviewed and extracted data from all the included studies on the relationship between MTHFR C677T polymorphism and T2DM in the Chinese Han population. The odds ratios (ORs) and their 95% confidence intervals (95%CIs) were used to evaluate the relationship. Fixed-effects and random-effects meta-analysis were used to pool ORs by the heterogeneity. Publication bias and sensitivity analysis were also examined. Results 29 studies were finally included in our meta-analysis, which contained 4656 individuals with T2DM and 2127 healthy controls. There was a significant relationship between MTHFR C677T polymorphism and T2DM under dominant (OR: 1.70, 95% CI: 1.42–2.02), recessive (OR: 1.48, 95% CI: 1.21–1.80), homozygous (OR: 1.89, 95% CI: 1.47–2.42), heterozygous (OR: 1.58, 95% CI: 1.33–1.87), and additive (OR: 1.46, 95% CI: 1.28–1.68) genetic model in a random-effects model. Subgroup analysis also reached similar results. Sensitivity analysis indicated that the overall result were dependable. Conclusions There was a significant relationship between MTHFR C677T polymorphism and T2DM in the Chinese Han population. The results of our meta-analysis suggested that MTHFR 677T allele might be a risk genetic factor of T2DM in the Chinese Han population. PMID:25047451

  7. Association of the methylenetetrahydrofolate reductase gene A1298C polymorphism with male infertility: a meta-analysis.

    PubMed

    Shen, Ouxi; Liu, Renping; Wu, Wei; Yu, Lugang; Wang, Xinru

    2012-01-01

    Published data on the association between the methylenetetrahydrofolate reductase (MTHFR) gene A1298C (rs1801131) polymorphism and male infertility risk are inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed. In this meta-analysis, a total of seven case-control studies including 1633 cases and 1735 controls were selected to evaluate the possible association. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of association in the additive model, dominant model, recessive model, and allele-frequency genetic model. In the overall analysis, the frequency of the C1298 allele (C vs. A) was significantly associated with susceptibility to male infertility (OR = 1.12, 95% CI = 1.00-1.26). A subgroup analysis of the subjects showed that MTHFR 1298C was associated with significant increased risk of azoospermia in homozygote comparison (CC vs. AA) and recessive mode (CC vs. AA/AC) (OR = 1.66 for CC vs. AA genotype; OR = 1.67 for CC vs. AA/AC genotype). However, no statistically significant increased risk of oligoasthenoteratozoospermia was found in any of the genetic models. In conclusion, this meta-analysis supports that the MTHFR A1298C polymorphism is capable of causing male infertility susceptibility, especially azoospermia. PMID:22175540

  8. Effect of MTHFR Gene Polymorphism Impact on Atherosclerosis via Genome-Wide Methylation.

    PubMed

    Lin, Xuefeng; Zhang, Wei; Lu, Qun; Lei, Xinjun; Wang, Tingzhong; Han, Xuanmao; Ma, Aiqun

    2016-01-01

    BACKGROUND Atherosclerosis seriously threats human health. Homocysteine is an independent risk factor closely related to DNA methylation. MTHFR C667T loci polymorphism is closely associated with homocysteine level. This study aimed to investigate the relationship among MTHFR C667T loci polymorphism, genome-wide methylation, and atherosclerosis. MATERIAL AND METHODS Blood sample was collected from 105 patients with coronary atherosclerosis and 105 healthy controls. Pyrosequencing methylation was used to detect LINE-1 methylation level. Polymerase chain reaction-restriction enzyme fragment length polymorphism (PCR-RFLP) was used to test MTHFR. RESULTS LINE-1 methylation level in the patient group was significantly lower than in the controls (t=5.007, P<0.001). MTHFR C667T genotype distribution presented marked differences in the 2 groups. TT genotype carriers had significantly increased risk of atherosclerosis (OR=3.56, P=0.009). Three different genotypes of MTHFR C667T loci showed different LINE-1 methylation level between the 2 groups (P<0.01). LINE-1 methylation level in TT and CT genotype carriers was obviously lower than in CC genotype carriers (P<0.05). CONCLUSIONS MTHFR C667T loci polymorphism may affect atherosclerosis by regulating genome methylation level. PMID:26828698

  9. Effect of MTHFR Gene Polymorphism Impact on Atherosclerosis via Genome-Wide Methylation

    PubMed Central

    Lin, Xuefeng; Zhang, Wei; Lu, Qun; Lei, Xinjun; Wang, Tingzhong; Han, Xuanmao; Ma, Aiqun

    2016-01-01

    Background Atherosclerosis seriously threats human health. Homocysteine is an independent risk factor closely related to DNA methylation. MTHFR C667T loci polymorphism is closely associated with homocysteine level. This study aimed to investigate the relationship among MTHFR C667T loci polymorphism, genome-wide methylation, and atherosclerosis. Material/Methods Blood sample was collected from 105 patients with coronary atherosclerosis and 105 healthy controls. Pyrosequencing methylation was used to detect LINE-1 methylation level. Polymerase chain reaction-restriction enzyme fragment length polymorphism (PCR-RFLP) was used to test MTHFR. Results LINE-1 methylation level in the patient group was significantly lower than in the controls (t=5.007, P<0.001). MTHFR C667T genotype distribution presented marked differences in the 2 groups. TT genotype carriers had significantly increased risk of atherosclerosis (OR=3.56, P=0.009). Three different genotypes of MTHFR C667T loci showed different LINE-1 methylation level between the 2 groups (P<0.01). LINE-1 methylation level in TT and CT genotype carriers was obviously lower than in CC genotype carriers (P<0.05). Conclusions MTHFR C667T loci polymorphism may affect atherosclerosis by regulating genome methylation level. PMID:26828698

  10. Dihydropyrimidine dehydrogenase 85T>C mutation is associated with ocular toxicity of 5-fluorouracil: a case report.

    PubMed

    Baskin, Yasemin; Amirfallah, Arsalan; Unal, Olcun Umit; Calibasi, Gizem; Oztop, Ilhan

    2015-01-01

    5-Fluorouracil (5-FU), the mainstay of solid tumor chemotherapy over the past 40 years, induces grade III-IV toxicities in up to 15% of patients with polymorphisms in the dihydropyrimidine dehydrogenase (DPYD), thymidylate synthase (TYMS), and methylenetetrahydrofolate reductase (MTHFR) genes. These toxicities include mucositis, neutropenia, nausea, diarrhea, myelosuppression, hand-foot syndrome, and rare ocular adverse effects. Here, we present the case of a female patient with rectal cancer who received 5-FU-based chemotherapy and developed grade III hand-foot syndrome and rare acute ocular adverse effects. Genetic analysis revealed that the patient had an 85T>C mutation in the DPYD gene resulting in a DPYD*9A allele. The clinical and molecular observations indicate that DPYD deficiency may be responsible for the severe ocular adverse effects observed in 5-FU-treated patients. Application of personalized therapy based on molecular testing should help clinicians provide the most effective chemotherapy agents and dose modifications for each patient, although further population-based pharmacogenetic trials for the 5-FU metabolism-related genes are necessary to minimize adverse effects and enhance clinical outcomes. PMID:24434920

  11. Association of a Methylene Tetrahydrofolate Reductase C677T Polymorphism with Several Blood Chemical Levels in a Chinese Population

    PubMed Central

    Wen, Can; Lv, Jiao-Feng; Wang, Ling; Zhu, Wei-Feng

    2015-01-01

    Background: The methylene tetrahydrofolate reductase (MTHFR) C677T polymorphism is associated with hypertension in certain populations. This study investigated the relationship between the MTHFR polymorphism and hypertension and correlated blood lipid indexes, including homocysteine (HCY), lipoprotein (a) [Lp (a)], high-density lipoprotein (HDL), low-density lipoprotein (LDL), apolipoprotein A I (Apo AI), Apo B, glucose (GLU), total cholesterol (TC), and triglyceride (TG), in a Chinese population. Materials and Methods: A total of 174 patients with hypertension and 634 healthy control individuals from Jiangxi Province were recruited between June 2012 and September 2012 for genotyping of the MTHFR C677T polymorphism using polymerase chain reaction-restriction fragment length polymorphism. Biochemical parameters were also assessed in these subjects and statistically compared to the MTHFR C677T polymorphism and the risk for hypertension. Results: HCY and Lp (a) levels were significantly higher in subjects with a MTHFR 677TT genotype than in those with a CC/CT genotype, independent of hypertension. The frequency of the TT genotype and the T allele in hypertension patients was significantly higher than in the healthy controls. Furthermore, in the male hypertension patient group, the average levels of HCY, HDL, Apo AI, and TC were significantly different from those in female hypertension patients (pHCY=0.001, pHDL=0.004, pApo AI<0.001, pTC=0.012). In the male control group, the average levels of HCY, HDL, Apo AI, GLU, and TC were significantly different from those of female controls (pHCY<0.001, pHDL<0.001, pApo AI<0.001, pGLU=0.001, and pTC=0.004). Conclusion: Our data demonstrate that the MTHFR C677T polymorphism is positively correlated with an increased risk of hypertension through an increase in HCY levels. The blood lipid correlative index was different between male and female hypertension patients and controls. PMID:25489783

  12. Association between the methylenetetrahydrofolate reductase c.677C>T polymorphism and bone mineral density: an updated meta-analysis.

    PubMed

    Li, Hong-Zhuo; Wang, Wei; Liu, Yi-Ling; He, Xiao-Feng

    2016-02-01

    Many studies have reported an association between the methylenetetrahydrofolate reductase (MTHFR) c.677C>T polymorphism and reduced bone mineral density (BMD), but results have been inconsistent. We, therefore, performed a meta-analysis to further explore this association. Twenty-one studies, comprising 33,045 subjects, analyzed the association of MTHFR c.677C>T with femoral neck BMD. Significant association with reduced BMD was observed in Caucasians (recessive model: WMD = -0.004 g/cm(2), 95 % CI -0.008 to -0.006), post-menopausal women (recessive model: WMD = -0.005 g/cm(2), 95 % CI -0.007 to -0.003), men (dominant model: WMD = -0.004 g/cm(2), 95 % CI -0.005 to -0.004; recessive model: WMD = -0.004 g/cm(2), 95 % CI -0.005 to -0.004; TT vs. CC: WMD = -0.006 g/cm(2), 95 % CI -0.006 to -0.006; CT vs. CC: WMD = -0.003 g/cm(2), 95 % CI -0.003 to -0.003), and cohort studies (recessive model: WMD = -0.003 g/cm(2), 95 % CI -0.006 to -0.001). Twenty-two studies, which included 32,271 subjects, analyzed the MTHFR c.677C>T association with lumbar spine BMD. Significant association with reduced BMD was observed in Caucasians, women, post-menopausal women, men, and cohort studies. Seven studies, comprising 6806 subjects, analyzed the MTHFR c.677C>T association with total hip BMD, but no significant association was observed in any population. Nine studies involving 5591 subjects analyzed the association with total body BMD. Significant association with reduced BMD was observed in overall and women subgroup analyses. In summary, this meta-analysis indicates that the MTHFR c.677C>T polymorphism is associated with reduced BMD in lumbar spine and femoral neck in Caucasians, post-menopausal women, and men, and with total body BMD in women. In addition, our results suggest that new studies examining the association between MTHFR c.677C>T polymorphism and BMD of lumbar spine and femoral neck in Asians is warranted, because I (2) > 75.0 % was observed. PMID:26231982

  13. Association of Transforming Growth Factor Alpha and Methylenetetrahydrofolate reductase gene variants with nonsyndromic cleft lip and palate in the Indian population

    PubMed Central

    Desai, Asavari L.; Dinesh, M. R.; Amarnath, B. C.; Dharma, R. M.; Akshai, K. R.; Prashanth, C. S.

    2014-01-01

    Objectives: The aim was to evaluate the relationship of the K-primer variant of the transforming growth factor-alpha (TGF-α) gene and C677T variant of the methylenetetrahydrofolate reductase (MTHFR) gene with nonsyndromic cleft lip and palate (CL/P) in the Indian population. Setting and Sample Population: The study group consisted of DNA samples of 25 subjects with nonsyndromic CL with or without cleft palate and 25 unrelated controls, already existing in the Department of Orthodontics, D.A.P.M.R.V. Dental College, Bengaluru, Karnataka, India. Materials and Methods: The DNA samples were divided into two categories: Group A which included the 25 subjects with nonsyndromic CL/P; and Group B, which consisted of the 25 unrelated controls. The polymerase chain reaction (PCR) test was done for amplification of the region of interest from the DNA samples. Restriction digestion was then performed on the amplified product using the restriction enzyme HinfI, separately for each of the variants. The digested PCR products were separated into channels on a 1.5% agarose gel containing ethidium bromide in an electrophoretic chamber. A U.V. transilluminator was used to see the specific bands of base pairs of the digested PCR products. Results: In Group A, the TGF-α gene variant was present in 16 subjects (P = 0.001) and MTHFR gene variant was present in 8 subjects (P = 0.185). A combination of both gene variants were present in seven subjects, which was an interesting finding. In Group B, four subjects tested positive for the TGF-α and MTHFR gene variants. Conclusions: The TGF-α gene variant and a combination of TGF-α + MTHFR gene variants significantly contribute to the development of nonsyndromic CL/P and can be considered as genetic markers for Indian population. The MTHFR gene variant, though a minor risk factor, cannot be considered as a genetic marker. PMID:25191068

  14. Analysis of Polymorphisms in Genes (AGT, MTHFR, GPIIIa, and GSTP1) Associated with Hypertension, Thrombophilia and Oxidative Stress in Mestizo and Amerindian Populations of México

    PubMed Central

    Juárez-Velázquez, Rocio; Canto, Patricia; Canto-Cetina, Thelma; Rangel-Villalobos, Hector; Rosas-Vargas, Haydee; Rodríguez, Maricela; Canizales-Quinteros, Samuel; Velázquez Wong, Ana Claudia; Ordoñez-Razo, Rosa María; Vilchis-Dorantes, Guadalupe; Coral-Vázquez, Ramón Mauricio

    2010-01-01

    Several polymorphisms related to hypertension, thrombophilia, and oxidative stress has been associated with the development of cardiovascular disease. We analyzed the frequency of M235T angiotensinogen (AGT), A222V 5,10 methylenete-trahydrofolate reductase (MTHFR), L33P glycoprotein IIIa (GPIIIa), and I105V glutathione S-transferase P1 (GSTP1) polymorphisms in 285 individuals belonging to Mexican-Mestizo and five Amerindian population from México, by real time PCR allelic discrimination. Allele and genotype frequencies were compared using χ2 tests. All populations followed the Hardy Weinberg equilibrium for assay markers with the exception of the Triki, whose were in Hardy Weinberg dysequilibrium for the glutathione S-transferase P1 polymorphism. Interestingly, according to all the analyzed single nucleotide polymorphisms (SNPs), the Triki population was the most differentiated and homogeneous group of the six populations analyzed. A comparison of our data with those previously published for some Caucasian, Asian and Black populations showed quite significant differences. These differences were remarkable with all the Mexican populations having a lower frequency of the 105V allele of the glutathione S-transferase P1 and reduced occurrence of the 222A allele of the 5,10 methylenetetrahydrofolate reductase. Our results show the genetic diversity among different Mexican populations and with other racial groups. PMID:20592457

  15. Association of methylenetetrahydrofolate reductase C677T and A1298C polymorphisms with colorectal cancer risk: A meta-analysis.

    PubMed

    Zhao, Mengmeng; Li, Xuelian; Xing, Chengzhong; Zhou, Baosen

    2013-09-01

    Colorectal cancer (CRC) is one of the most common types of cancer worldwide and a leading cause of cancer-related mortality. This meta-analysis was conducted to determine the effect of methylenetetrahydrofolate reductase (MTHFR) mutants on the risk of CRC. A literature search was conducted on PubMed, Medline and the China National Knowledge Infrastructure (CNKI) databases. Eligible studies were collected based on rigorous criteria of inclusion. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated by the fixed- or random-effects model. After all the studies were pooled, the OR of CRC for individuals carrying the MTHFR 677TT genotype, compared to the CC genotype, was 0.89 (95% CI: 0.82-0.97). When analyzed by ethnicity, Asians with the MTHFR 1298CC genotype exhibited a decreased risk of CRC (OR=0.69; 95% CI: 0.54-0.89). In a mixed population, a significantly reduced risk of CRC was observed among carriers of the 677TT (OR=0.86; 95% CI: 0.76-0.96) and the 1298CC (OR=0.82; 95% CI: 0.69-0.98) genotypes, compared to the wild-type homozygous genotype. In the subgroup of colon cancer, the OR of 677TT vs. CC+CT was 0.83 (95% CI: 0.72-0.96) and the OR of 1298CC vs. AA+AC was 0.81 (95% CI: 0.69-0.96). In the rectal cancer subgroup, the OR of 677TT vs. CC+CT was 0.86 (95% CI: 0.77-0.97). Therefore, this meta-analysis suggested that the MTHFR 677T and 1298C alleles were associated with a low risk of CRC. PMID:24649029

  16. Homocysteine and methylenetetrahydrofolate reductase C677T and A1298C polymorphisms in Tunisian patients with severe coronary artery disease.

    PubMed

    Ghazouani, Lakhdar; Abboud, Nesrine; Mtiraoui, Nabil; Zammiti, Walid; Addad, Faouzi; Amin, Haitham; Almawi, Wassim Y; Mahjoub, Touhami

    2009-02-01

    Elevation in homocysteine and methylenetetrahydrofolate reductase (MTHFR) gene variants, C677T and A1298C, have been linked with atherothrombosis. However their exact contribution to coronary artery disease (CAD) remains controversial. Moreover, data from Tunisian patients are scarse. We examined the association of MTHFR C677T and A1298C, and changes in plasma homocysteine in 352 Tunisian patients with angiographically-demonstrated CAD, and 390 age and gender-matched healthy subjects. Significantly higher frequency of 677T allele and homozygous 677T/T genotype were seen in patients vs. control subjects; the distribution of A1298C alleles and genotypes being comparable in the two groups. Specific MTHFR haplotypes comprising 677C/1298A (P < 0.001) and 677T/1298A (P < 0.001) were negatively and positively associated with CAD, respectively. Plasma homocysteine concentration was significantly higher in 677T/T genotype with respect to 677C/C and 677C/T genotypes in patients and controls, but homocysteine levels were generally comparable between both groups. Univariate analysis identified 677T/1298A (P = 0.033) haplotype to be positively associated with CAD, which remained significant by multivariate analysis after adjusting for a number of covariates (P = 0.038). MTHFR C677T, but not A1298C SNPs, is associated with CAD and with elevated homocysteine levels in a Tunisian population. The negative and positive association of the 1298A allele with CAD being indicative of a neutral (absent) effect of the A1298C SNP on disease pathogenesis. PMID:18204887

  17. Folate Intake at RDA Levels Is Inadequate for Mexican American Men with the Methylenetetrahydrofolate Reductase 677TT Genotype123

    PubMed Central

    Solis, Claudia; Veenema, Kristin; Ivanov, Alexandre A.; Tran, Sally; Li, Rui; Wang, Wei; Moriarty, David J.; Maletz, Charles V.; Caudill, Marie A.

    2009-01-01

    Since the establishment of the 1998 folate recommended dietary allowance (RDA), the methylenetetrahydrofolate reductase (MTHFR) 677C→T variant has emerged as a strong modifier of folate status. This controlled feeding study investigated the adequacy of the RDA, 400 μg/d as dietary folate equivalents (DFE), for Mexican American men with the MTHFR 677CC or TT genotype. Because of the interdependency between folate and choline, the influence of choline intake on folate status was also assessed. Mexican American men (n = 60; 18–55 y) with the MTHFR 677CC (n = 31) or TT (n = 29) genotype consumed 438 μg DFE/d and total choline intakes of 300, 550 (choline adequate intake), 1100, or 2200 mg/d for 12 wk. Folate status response was assessed via serum folate (SF), RBC folate, plasma total homocysteine (tHcy), and urinary folate. SF decreased (P < 0.001) 66% to 7.9 ± 0.7 nmol/L (means ± SEM) in men with the 677TT genotype and 62% to 11.3 ± 0.9 nmol/L in the 677CC genotype. Plasma tHcy increased (P < 0.0001) 170% to 31 ± 3 μmol/L in men with the 677TT genotype and 18% to 11.6 ± 0.3 μmol/L in the 677CC genotype. At the end of the study, 34% (677TT) and 16% (677CC) had SF concentrations <6.8 nmol/L and 79% (677TT) and 7% (677CC) had tHcy concentrations >14 μmol/L. Choline intake did not influence the response of the measured variables. These data showed that the folate RDA is not adequate for men of Mexican descent, particularly for those with the MTHFR 677TT genotype, and demonstrated a lack of influence of choline intake on the folate status variables measured in this study. PMID:18156406

  18. Association of the methylenetetrahydrofolate reductase gene C677T polymorphism with the risk of male infertility: a meta-analysis.

    PubMed

    Zhu, Xudong; Liu, Zhiguo; Zhang, Maochen; Gong, Ruihong; Xu, Yajun; Wang, Baoming

    2016-03-01

    Several molecular epidemiological studies have been conducted to examine the association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and male infertility susceptibility, but the results remain inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed. In this meta-analysis, a total of 26 case-control studies including 5659 infertility cases and 5528 controls were selected to evaluate the possible association. The pooled odds ratios (ORs) with 95% confidence intervals (95% CIs) were used to assess the strength of association of C677T polymorphism with male infertility in the additive model, dominant model, recessive model and allele-frequency genetic model. In the overall analysis, the frequency of the 677T allele was significantly associated with male infertility susceptibility (OR = 2.32, 95%CI = 2.04-2.65 for TT vs. CC genotype; OR = 1.09, 95%CI = 1.00-1.19 for CT vs. CC genotype; OR = 1.19, 95%CI = 1.10-1.29 for CT/TT vs. CC genotype; OR = 1.54, 95%CI = 1.36-1.74 for TT vs. CC/TT genotype; OR = 1.22, 95%CI = 1.15-1.30 for T vs. C allele). A subgroup analysis of the subjects showed that significantly strong association between MTHFR C677T polymorphism and male infertility was present only in Asians, but not in Caucasians. Additionally, MTHFR C677T was associated with a significant increase in the risk of azoospermia in all genetic models. Meanwhile, no significantly increased risks of oligoasthenotertozoospermia (OAT) were found in most of the genetic models. In conclusion, this meta-analysis is in favor that the MTHFR C677T polymorphism is capable of causing male infertility susceptibility, especially in Asians and the subgroup of azoospermia. PMID:26584688

  19. Homocysteine and Coronary Heart Disease: Meta-analysis of MTHFR Case-Control Studies, Avoiding Publication Bias

    PubMed Central

    Verhoef, Petra; Dötsch-Klerk, Mariska; Lathrop, Mark; Xu, Peng; Nordestgaard, Børge G.; Holm, Hilma; Hopewell, Jemma C.; Saleheen, Danish; Tanaka, Toshihiro; Anand, Sonia S.; Chambers, John C.; Kleber, Marcus E.; Ouwehand, Willem H.; Yamada, Yoshiji; Elbers, Clara; Peters, Bas; Stewart, Alexandre F. R.; Reilly, Muredach M.; Thorand, Barbara; Yusuf, Salim; Engert, James C.; Assimes, Themistocles L.; Kooner, Jaspal; Danesh, John; Watkins, Hugh; Samani, Nilesh J.

    2012-01-01

    Background Moderately elevated blood levels of homocysteine are weakly correlated with coronary heart disease (CHD) risk, but causality remains uncertain. When folate levels are low, the TT genotype of the common C677T polymorphism (rs1801133) of the methylene tetrahydrofolate reductase gene (MTHFR) appreciably increases homocysteine levels, so “Mendelian randomization” studies using this variant as an instrumental variable could help test causality. Methods and Findings Nineteen unpublished datasets were obtained (total 48,175 CHD cases and 67,961 controls) in which multiple genetic variants had been measured, including MTHFR C677T. These datasets did not include measurements of blood homocysteine, but homocysteine levels would be expected to be about 20% higher with TT than with CC genotype in the populations studied. In meta-analyses of these unpublished datasets, the case-control CHD odds ratio (OR) and 95% CI comparing TT versus CC homozygotes was 1.02 (0.98–1.07; p = 0.28) overall, and 1.01 (0.95–1.07) in unsupplemented low-folate populations. By contrast, in a slightly updated meta-analysis of the 86 published studies (28,617 CHD cases and 41,857 controls), the OR was 1.15 (1.09–1.21), significantly discrepant (p = 0.001) with the OR in the unpublished datasets. Within the meta-analysis of published studies, the OR was 1.12 (1.04–1.21) in the 14 larger studies (those with variance of log OR<0.05; total 13,119 cases) and 1.18 (1.09–1.28) in the 72 smaller ones (total 15,498 cases). Conclusions The CI for the overall result from large unpublished datasets shows lifelong moderate homocysteine elevation has little or no effect on CHD. The discrepant overall result from previously published studies reflects publication bias or methodological problems. Please see later in the article for the Editors' Summary PMID:22363213

  20. MTHFR 677C>T Polymorphism and the Risk of Breast Cancer: Evidence from an Original Study and Pooled Data for 28031 Cases and 31880 Controls

    PubMed Central

    Sekhar, Deepa; Francis, Amirtharaj; Gupta, Nishi; Konwar, Rituraj; Kumar, Sandeep; Kumar, Surender; Thangaraj, Kumarasamy; Rajender, Singh

    2015-01-01

    Background Methylenetetrahydrofolate reductase (MTHFR) acts at an important metabolic point in the regulation of cellular methylation reaction. It assists in the conversion of 5, 10-methylenetetrahydrofolate to 5-methyltetrahydrofolate. The latter aids in remethylation of homocysteine to de novo methionine that is required for DNA synthesis. The objective of this study was to examine the effect of MTHFR 677 C>T polymorphism on the risk of breast cancer in the Indian sub-continent. Methods and Results We genotyped 677 C>T locus in 1096 individuals that were classified into cases (N=588) and controls (N=508). Genotype data were analyzed using chi-square test. No significant difference was observed in the distribution of genotypes between cases and controls in north Indian (P = 0.932), south Indian (P = 0.865), and pooled data (P = 0.680). To develop a consensus regarding the impact of 677C>T polymorphism on breast cancer risk, we also conducted a meta-analysis on 28031 cases and 31880 controls that were pooled from sixty one studies. The overall summary estimate upon meta-analysis suggested no significant correlation between the 677C>T substitution and breast cancer in the dominant model (Fixed effect model: OR = 0.97, P=0.072, Random effects model: OR = 0.96, P = 0.084) or the recessive model (Fixed effect model: OR = 1.05, P = 0.089; Random effects model: OR= 1.08, P= 0.067). Conclusion 677 C>T substitution does not affect breast cancer risk in the Indo-European and Dravidian populations of India. Analysis on pooled data further ruled out association between the 677 C>T polymorphism and breast cancer. Therefore, 677 C>T substitution does not appear to influence the risk of breast cancer. PMID:25803740

  1. Strong Association of 677 C>T Substitution in the MTHFR Gene with Male Infertility - A Study on an Indian Population and a Meta-Analysis

    PubMed Central

    Gupta, Nishi; Gupta, Saraswati; Dama, Madhukar; David, Archana; Khanna, Geeta; Khanna, Anil; Rajender, Singh

    2011-01-01

    Background Methylenetetrahydrofolate reductase (MTHFR) is an important enzyme of folate and methionine metabolism, making it crucial for DNA synthesis and methylation. The objective of this study was to analyze MTHFR gene 677C>T polymorphism in infertile male individuals from North India, followed by a meta-analysis on our data and published studies. Methodology/Principal Findings We undertook genotyping on a total of 837 individuals including well characterized infertile (N = 522) and confirmed fertile (N = 315) individuals. The SNP was typed by direct DNA sequencing. Chi square test was done for statistical analysis. Published studies were searched using appropriate keywords. Source of data collection for meta-analysis included ‘Pubmed’, ‘Ovid’ and ‘Google Scholar’. Those studies analyzing 677C>T polymorphism in male infertility and presenting all relevant data were included in meta-analysis. The genotype data for infertile subjects and fertile controls was extracted from each study. Chi square test was done to obtain odds ratio (OR) and p-value. Meta-analysis was performed using Comprehensive Meta-analysis software (Version 2). The frequency of mutant (T) allele (p = 0.0025) and genotypes (CT+TT) (p = 0.0187) was significantly higher in infertile individuals in comparison to fertile controls in our case-control study. The overall summary estimate (OR) for allele and genotype meta-analysis were 1.304 (p = 0.000), 1.310 (p = 0.000), respectively, establishing significant association of 677C>T polymorphism with male infertility. Conclusions/Significance 677C>T substitution associated strongly with male infertility in Indian population. Allele and genotype meta-analysis also supported its strong correlation with male infertility, thus establishing it as a risk factor. PMID:21799811

  2. MTHFR C677T genotype as a risk factor for epilepsy including post-traumatic epilepsy in a representative military cohort.

    PubMed

    Scher, Ann I; Wu, Holly; Tsao, Jack W; Blom, Henk J; Feit, Preethy; Nevin, Remington L; Schwab, Karen A

    2011-09-01

    The well-studied C677T variant in the methylenetetrahydrofolate reductase (MTHFR) enzyme is a biologically plausible genetic risk factor for seizures or epilepsy. First, plasma/serum levels of homocysteine, a pro-convulsant, are moderately elevated in individuals with the homozygote TT genotype. Furthermore, the TT genotype has been previously linked with migraine with aura-a comorbid condition-and with alcohol withdrawal seizures. Finally, several small studies have suggested that the TT genotype may be overrepresented in epilepsy patients. In this study, we consider whether the MTHFR C677T or A1298C variants are associated with risk of epilepsy including post-traumatic epilepsy (PTE) in a representative military cohort. Study subjects were selected from the cohort of military personnel on active duty during the years 2003 through 2007 who had archived serum samples at the DoD Serum Repository, essentially all active duty personnel during this time frame. We randomly selected 800 epilepsy patients and 800 matched controls based on ICD-9-CM diagnostic codes. We were able to isolate sufficient genetic material from the archived sera to genotype approximately 85% of our study subjects. The odds of epilepsy were increased in subjects with the TT versus CC genotype (crude OR=1.52 [1.04-2.22], p=0.031; adjusted OR=1.57 [1.07-2.32], p=0.023). In our sensitivity analysis, risk was most evident for patients with repeated rather than single medical encounters for epilepsy (crude OR=1.85 [1.14-2.97], p=0.011, adjusted OR=1.95 [1.19-3.19], p=0.008), and particularly for PTE (crude OR=3.14 [1.41-6.99], p=0.005; adjusted OR=2.55 [1.12-5.80], p=0.026). Our early results suggest a role for the common MTHFR C677T variant as a predisposing factors for epilepsy including PTE. Further exploration of baseline homocysteine and folate levels as predictors of seizure risk following traumatic brain injury is warranted. PMID:21787169

  3. Flavodiiron Oxygen Reductase from Entamoeba histolytica

    PubMed Central

    Gonçalves, Vera L.; Vicente, João B.; Pinto, Liliana; Romão, Célia V.; Frazão, Carlos; Sarti, Paolo; Giuffrè, Alessandro; Teixeira, Miguel

    2014-01-01

    Flavodiiron proteins (FDPs) are a family of enzymes endowed with bona fide oxygen- and/or nitric-oxide reductase activity, although their substrate specificity determinants remain elusive. After a comprehensive comparison of available three-dimensional structures, particularly of FDPs with a clear preference toward either O2 or NO, two main differences were identified near the diiron active site, which led to the construction of site-directed mutants of Tyr271 and Lys53 in the oxygen reducing Entamoeba histolytica EhFdp1. The biochemical and biophysical properties of these mutants were studied by UV-visible and electron paramagnetic resonance (EPR) spectroscopies coupled to potentiometry. Their reactivity with O2 and NO was analyzed by stopped-flow absorption spectroscopy and amperometric methods. These mutations, whereas keeping the overall properties of the redox cofactors, resulted in increased NO reductase activity and faster inactivation of the enzyme in the reaction with O2, pointing to a role of the mutated residues in substrate selectivity. PMID:25151360

  4. Genetic Association between Methylenetetrahydrofolate Reductase Gene Polymorphism and Risk of Osteonecrosis of the Femoral Head

    PubMed Central

    Chai, Wei; Zhang, Zhendong; Ni, Ming; Geng, Peiliang; Lian, Zijian; Zhang, Guoqiang; Shi, Lewis L.; Chen, Jiying

    2015-01-01

    Background. Methylenetetrahydrofolate reductase (MTHFR) SNP rs1801133 has been frequently investigated in recent years. Relevant candidate gene association studies with this SNP and osteonecrosis of the femoral head (ONFH) reported conflicting results. Meta-analysis provides a method to combine these data and to determine the association in a larger sample size. Method. We conducted a systematic search to identify possible studies. Four pooled ORs (odds ratios, T versus C, TT versus CC, TT/CT versus CC, and TT versus CT/CC), along with 95% confidence interval (CI), were calculated to evaluate the association between SNP rs1801133 and ONFH susceptibility. Both fixed effects model and random effects model were used. Findings. We eventually included twelve studies in this analysis, with results showing no overall association between ONFH susceptibility and SNP rs1801133 (T versus C: OR = 1.15, 95% CI = 0.971.38; TT versus CC: OR = 1.15, 95% CI = 0.911.46; TT/CT versus CC: OR = 1.09, 95% CI = 0.951.25; and TT versus CT/CC: OR = 1.16, 95% CI = 0.931.45). When stratified based on ethnicity, the results were still not significant. Conclusion. Our findings are generally supportive of no association between MTHFR SNP rs1801133 and the etiology of ONFH. PMID:25688352

  5. Association Between MTHFR Genetic Variants and Multiple Sclerosis in a Southern Iranian Population

    PubMed Central

    Naghibalhossaini, Fakhraddin; Ehyakonandeh, Hesam; Nikseresht, Alireza; Kamali, Eskandar

    2015-01-01

    Multiple sclerosis (MS) is a demyelinating neuro- inflammatory autoimmune disease of the central nervous system. Genetic predisposition has long been suspected in the etiology of this disease. The association between MTHFR polymorphisms and MS has been ivestigated in different ethnic groups. We investigated the association between MTHFR C677T and A1298C missense variants and MS in 180 patients and 231 age- and gender-matched healthy controls in a Southern Iranian population. The mutagenically separated PCR (MS-PCR) and PCR-RFLP methods were used to genotype MTHFR at position 677 and 1298, respectively. Compared with controls, we observed a strong association between two MTHFR variants and the risk of developing MS. Subjects carrying 677T allele (CT and TT genotypes) had increased susceptibility to MS as compared to those carrying CC genotype (odds ratio (OR) for CT= 2.9, 95% confidence interval (95% CI)= 1.88-4.49; OR for TT= 6.23, 95% CI= 3.08-12.59). The variant 1298AC genotype also increased the risk for MS among our study population (OR= 2.14, 95% CI= 1.37-3.34). Combined genotype analysis for two MTHFR SNPs revealed that compared to the wild type genotypes (677CC/1298AA), 3 genotypes including TT/AC, CT/AC, and TT/AA were significantly at increased risk for MS development (OR= 13.9, 5.3, and 4.9, respectively). Our results suggest a possible gene dose- dependent association between MTHFR mutrant alleles and the risk of MS development. PMID:26261797

  6. Association Between MTHFR Genetic Variants and Multiple Sclerosis in a Southern Iranian Population.

    PubMed

    Naghibalhossaini, Fakhraddin; Ehyakonandeh, Hesam; Nikseresht, Alireza; Kamali, Eskandar

    2015-01-01

    Multiple sclerosis (MS) is a demyelinating neuro- inflammatory autoimmune disease of the central nervous system. Genetic predisposition has long been suspected in the etiology of this disease. The association between MTHFR polymorphisms and MS has been ivestigated in different ethnic groups. We investigated the association between MTHFR C677T and A1298C missense variants and MS in 180 patients and 231 age- and gender-matched healthy controls in a Southern Iranian population. The mutagenically separated PCR (MS-PCR) and PCR-RFLP methods were used to genotype MTHFR at position 677 and 1298, respectively. Compared with controls, we observed a strong association between two MTHFR variants and the risk of developing MS. Subjects carrying 677T allele (CT and TT genotypes) had increased susceptibility to MS as compared to those carrying CC genotype (odds ratio (OR) for CT= 2.9, 95% confidence interval (95% CI)= 1.88-4.49; OR for TT= 6.23, 95% CI= 3.08-12.59). The variant 1298AC genotype also increased the risk for MS among our study population (OR= 2.14, 95% CI= 1.37-3.34). Combined genotype analysis for two MTHFR SNPs revealed that compared to the wild type genotypes (677CC/1298AA), 3 genotypes including TT/AC, CT/AC, and TT/AA were significantly at increased risk for MS development (OR= 13.9, 5.3, and 4.9, respectively). Our results suggest a possible gene dose- dependent association between MTHFR mutrant alleles and the risk of MS development. PMID:26261797

  7. Human brain aldehyde reductases: relationship to succinic semialdehyde reductase and aldose reductase.

    PubMed

    Hoffman, P L; Wermuth, B; von Wartburg, J P

    1980-08-01

    Human brain contains multiple forms of aldehyde-reducing enzymes. One major form (AR3), as previously shown, has properties that indicate its identity with NADPH-dependent aldehyde reductase isolated from brain and other organs of various species; i.e., low molecular weight, use of NADPH as the preferred cofactor, and sensitivity to inhibition by barbiturates. A second form of aldehyde reductase ("SSA reductase") specifically reduces succinic semialdehyde (SSA) to produce gamma-hydroxybutyrate. This enzyme form has a higher molecular weight than AR3, and uses NADH as well as NADPH as cofactor. SSA reductase was not inhibited by pyrazole, oxalate, or barbiturates, and the only effective inhibitor found was the flavonoid quercetine. Although AR3 can also reduce SSA, the relative specificity of SSA reductase may enhance its in vivo role. A third form of human brain aldehyde reductase, AR2, appears to be comparable to aldose reductases characterized in several species, on the basis of its activity pattern with various sugar aldehydes and its response to characteristic inhibitors and activators, as well as kinetic parameters. This enzyme is also the most active in reducing the aldehyde derivatives of biogenic amines. These studies suggest that the various forms of human brain aldehyde reductases may have specific physiological functions. PMID:6778961

  8. Significance of 5,10-methylenetetrahydrofolate reductase gene variants in acute lymphoblastic leukemia in Indian population: an experimental, computational and meta-analysis.

    PubMed

    Bellampalli, Ravishankara; Phani, Nagaraja M; Bhat, Kamalakshi G; Prasad, Krishna; Bhaskaranand, Nalini; Guruprasad, Kanive P; Rai, Padmalatha S; Satyamoorthy, Kapaettu

    2015-05-01

    Acute lymphoblastic leukemia (ALL) arises due to several genetic alterations in progenitor cells, and methotrexate is frequently used as part of the treatment regimen. Although there is evidence for an effect of 5,10-methylenetetrahydrofolate reductase gene (MTHFR) C677T and A1298C variations on drug response in ALL, its risk association for ALL is still unresolved. In a case-control study of 203 patients with ALL and 246 controls and meta-analysis in the Indian population, we showed an insignificant association of MTHFR C677T and A1298C genotypes with childhood and adult ALL. Comprehensive in silico characterization of non-synonymous single nucleotide polymorphisms (nsSNPs) and SNPs of the 3' untranslated region (UTR) revealed nine nsSNPs as deleterious, and three SNPs in the 3'UTR could possibly alter the binding of miRNAs. The study revealed that several overlooked SNPs may contribute to the risk of ALL susceptibility and further studies of these SNPs with functional characterization in a large sample size are required to understand the significant role of MTHFR in ALL development. PMID:25115513

  9. Nitrate and periplasmic nitrate reductases

    PubMed Central

    Sparacino-Watkins, Courtney; Stolz, John F.; Basu, Partha

    2014-01-01

    The nitrate anion is a simple, abundant and relatively stable species, yet plays a significant role in global cycling of nitrogen, global climate change, and human health. Although it has been known for quite some time that nitrate is an important species environmentally, recent studies have identified potential medical applications. In this respect the nitrate anion remains an enigmatic species that promises to offer exciting science in years to come. Many bacteria readily reduce nitrate to nitrite via nitrate reductases. Classified into three distinct types – periplasmic nitrate reductase (Nap), respiratory nitrate reductase (Nar) and assimilatory nitrate reductase (Nas), they are defined by their cellular location, operon organization and active site structure. Of these, Nap proteins are the focus of this review. Despite similarities in the catalytic and spectroscopic properties Nap from different Proteobacteria are phylogenetically distinct. This review has two major sections: in the first section, nitrate in the nitrogen cycle and human health, taxonomy of nitrate reductases, assimilatory and dissimilatory nitrate reduction, cellular locations of nitrate reductases, structural and redox chemistry are discussed. The second section focuses on the features of periplasmic nitrate reductase where the catalytic subunit of the Nap and its kinetic properties, auxiliary Nap proteins, operon structure and phylogenetic relationships are discussed. PMID:24141308

  10. The role of methylenetetrahydrofolate reductase C677T polymorphism on the peripheral blood natural killer cell proportion in women with unexplained recurrent miscarriages

    PubMed Central

    Park, Chan Woo; Han, Ae Ra; Kwak-Kim, Joanne; Park, So Yeon; Han, Jung Yeol; Koong, Mi Kyoung; Song, In Ok

    2011-01-01

    Objective To examine the association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and hyperhomocysteinemia in women with unexplained recurrent miscarriages (RM) and to investigate the association between MTHFR genotype variants and alloimmune activation, proportion of peripheral blood natural killer (pbNK) cells. Methods A total of 39 patients with a history of two or more unexplained miscarriages were recruited to this study. The controls were women who had a live birth without a history of RM (n=50). The proportion of pbNK cells was measured by flow cytometry. Plasma homocysteine levels and the incidence of the MTHFR variant of the RM and control groups were compared. The proportion of pbNK cells was compared to the MTHFR variants in the RM group. Results No differences were found between the two groups' mean plasma homocysteine levels (7.61.5 mol/L vs. 7.12.1 mol/L) or incidence of the MTHFR genotype variant (CC, 35% vs. 33%; CT, 40% vs. 53%; and TT, 25% vs. 14%). In the RM group, individuals with the TT variant (7.71.1 mol/L) had higher homocysteine levels than those with the CC and CT variants (7.41.9 mol/L and 7.41.2 mol/L) and those with the CT variant (19.28.1%) had a higher proportion of CD3-/CD56+ pbNK cells than those with the CC and TT variants (17.76.6% and 17.97. 0%), but the results of both comparisons were statistically insignificant. Conclusion These preliminary results show no difference in plasma homocysteine levels between the RM and control groups or among MTHFR genotype variants in the RM group, which may suggest that the plasma homocysteine level is difficult to use as a predictive marker of RM in the Korean population. A study of a larger number of patients is needed. PMID:22384438

  11. Development and Characterization of Reference Materials for MTHFR, SERPINA1, RET, BRCA1, and BRCA2 Genetic Testing

    PubMed Central

    Barker, Shannon D.; Bale, Sherri; Booker, Jessica; Buller, Arlene; Das, Soma; Friedman, Kenneth; Godwin, Andrew K.; Grody, Wayne W.; Highsmith, Edward; Kant, Jeffery A.; Lyon, Elaine; Mao, Rong; Monaghan, Kristin G.; Payne, Deborah A.; Pratt, Victoria M.; Schrijver, Iris; Shrimpton, Antony E.; Spector, Elaine; Telatar, Milhan; Toji, Lorraine; Weck, Karen; Zehnbauer, Barbara; Kalman, Lisa V.

    2009-01-01

    Well-characterized reference materials (RMs) are integral in maintaining clinical laboratory quality assurance for genetic testing. These RMs can be used for quality control, monitoring of test performance, test validation, and proficiency testing of DNA-based genetic tests. To address the need for such materials, the Centers for Disease Control and Prevention established the Genetic Testing Reference Material Coordination Program (GeT-RM), which works with the genetics community to improve public availability of characterized RMs for genetic testing. To date, the GeT-RM program has coordinated the characterization of publicly available genomic DNA RMs for a number of disorders, including cystic fibrosis, Huntington disease, fragile X, and several genetic conditions with relatively high prevalence in the Ashkenazi Jewish population. Genotypic information about a number of other cell lines has been collected and is also available. The present study includes the development and commutability/genotype characterization of 10 DNA samples for clinically relevant mutations or sequence variants in the following genes: MTHFR; SERPINA1; RET; BRCA1; and BRCA2. DNA samples were analyzed by 19 clinical genetic laboratories using a variety of assays and technology platforms. Concordance was 100% for all samples, with no differences observed between laboratories using different methods. All DNA samples are available from Coriell Cell Repositories and characterization information can be found on the GeT-RM website. PMID:19767587

  12. Association between premature ovarian failure, polymorphisms in MTHFR and MTRR genes and serum homocysteine concentration.

    PubMed

    Hou, Ningning; Chen, Songchang; Chen, Feng; Jiang, Minmin; Zhang, Junyu; Yang, Yanmei; Zhu, Bo; Bai, Xiaoxia; Hu, Yuting; Huang, Hefeng; Xu, Chenming

    2016-04-01

    This study investigated the association between premature ovarian failure (POF), MTHFR C677T/A1298C and MTRR A66G genotypes and serum homocysteine (Hcy) concentration. A prospective study was conducted in Chinese women, which included POF patients (n = 180) and controls (n = 195). Peripheral blood samples were used to determine MTHFR C677T/A1298C and MTRR A66G genotypes, and serum Hcy and sex hormone concentrations. Results showed that serum Hcy concentrations of POF patients were significantly higher than those of controls (P < 0.0001). In POF patients, serum Hcy concentrations were significantly correlated with oestradiol and FSH concentrations (r = -0.174, P = 0.037 and r = +0.238, P = 0.006, respectively). There were no significant differences in the distributions of MTHFR C677T/A1298C or MTRR A66G genotypes between the two groups. However, these genetic variants influenced serum Hcy concentrations in POF patients, especially for MTRR 66 AA/AG/GG genotypes, which were significantly correlated with the patients' Hcy concentrations (τ = 0.166, P = 0.033). These results suggest that serum Hcy concentrations in Chinese POF patients are increased and correlated with serum oestradiol/FSH concentrations. In conclusion, MTHFR C667T/A1298C and MTRR A66G genotypes are not associated with POF development, but they affect the patients' serum Hcy concentrations. PMID:26874989

  13. The MTHFR C677T Variant is Associated with Responsiveness to Disulfiram Treatment for Cocaine Dependency

    PubMed Central

    Spellicy, Catherine J.; Kosten, Thomas R.; Hamon, Sara C.; Harding, Mark J.; Nielsen, David A.

    2013-01-01

    Objective: Disulfiram is a one of the few pharmacotherapies for cocaine addiction that shows promise. Since disulfiram and cocaine both affect levels of global methylation we hypothesized the MTHFR gene, whose product is involved in supplying methyl groups for DNA and protein methylation, may be associated with responsiveness to disulfiram in cocaine-dependent individuals. Methods: Sixty-seven cocaine-dependent patients were stabilized on methadone for 2 weeks and then randomized into disulfiram (250 mg/day, N = 32) and placebo groups (N = 35) for 10 weeks. Patients were genotyped for the MTHFR (rs1801133, also known as C677T) polymorphism and the data was evaluated for association with cocaine-free urines in the disulfiram or placebo groups. Data from patients that completed all 10 weeks of the study (N = 56) were analyzed using repeated measures analysis of variance (ANOVA), corrected for population structure. Results: The CT or TT MTHFR genotype group (N = 32) dropped from 73 to 52% cocaine-positive urines on disulfiram (p = 0.0001), while the placebo group showed no treatment effect. The CC MTHFR genotype group (N = 24) showed a smaller, but still significant, reduction in cocaine-positive urines on disulfiram compared to placebo; 81–69% (p = 0.007). Conclusion: This study indicates that a patient’s MTHFR genotype may be used to identify individuals who might show improved response to disulfiram treatment for cocaine dependence. Clinical Trial: Pharmacogenetics of Disulfiram for Cocaine, clinicaltrials.gov/ct2/show/NCT00149630, NIDA-18197-2, NCT00149630. PMID:23335901

  14. Association between MTHFR A1298C polymorphism and hepatocellular carcinoma risk

    PubMed Central

    Zhang, Haiyan; Li, Guang; Zhang, Zhen

    2015-01-01

    Background: Hepatocarcinogenesis is a complex process that is influenced by many factors. Several studies have investigated the relationship between MTHFR A1298C polymorphism and hepatocellular carcinoma (HCC) risk, but the results are inconsistent. Therefore, we performed a meta-analysis covering a large sample size to address this controversy. Methods: Eligible studies were searched using PubMed, EMBASE, and China National Knowledge Infrastructure (CNKI) databases. A total of 7 studies from 6 publications with 2035 cases and 3096 controls were included. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) was calculated by the fixed or random effects to evaluate the correlation between MTHFR A1298C polymorphism and HCC risk. The Q statistic and I2 statistic were used to assess the statistical heterogeneity among studies. Publication bias was evaluated by Egger’s linear regression test and Begg’s funnel plot. Results: In present study, the results showed that MTHFR A1298C polymorphism was not significantly associated with risk of HCC based on CC + AC vs. AA genetic model (OR=1.01, 95% CI=0.90-1.13). Similarly, in the subgroup analysis by ethnicity, no significant HCC risk was found in Asian population (OR=1.02, 95% CI=0.91-1.14). In the subgroup analysis based on source of control, we found that MTHFR A1298C polymorphism showed no effects on the occurrence of HCC in the population-based (PB) and hospital-based (HB) group (OR=0.97, 95% CI=0.83-1.15; OR=1.04, 95% CI=0.89-1.21). Conclusion: This meta-analysis suggested that MTHFR A1298C polymorphism may not be a risk factor for HCC. PMID:26309569

  15. Ribonucleotide reductases: essential enzymes for bacterial life

    PubMed Central

    Torrents, Eduard

    2014-01-01

    Ribonucleotide reductase (RNR) is a key enzyme that mediates the synthesis of deoxyribonucleotides, the DNA precursors, for DNA synthesis in every living cell. This enzyme converts ribonucleotides to deoxyribonucleotides, the building blocks for DNA replication, and repair. Clearly, RNR enzymes have contributed to the appearance of genetic material that exists today, being essential for the evolution of all organisms on Earth. The strict control of RNR activity and dNTP pool sizes is important, as pool imbalances increase mutation rates, replication anomalies, and genome instability. Thus, RNR activity should be finely regulated allosterically and at the transcriptional level. In this review we examine the distribution, the evolution, and the genetic regulation of bacterial RNRs. Moreover, this enzyme can be considered an ideal target for anti-proliferative compounds designed to inhibit cell replication in eukaryotic cells (cancer cells), parasites, viruses, and bacteria. PMID:24809024

  16. NADPH-dependent reductases in dog thyroid: comparison of a third enzyme "glyceraldehyde reductase" to dog thyroid aldehyde reductase.

    PubMed

    Schaffhauser, M A; Sato, S; Kador, P F

    1996-03-01

    The increased incidence of thyroiditis reported to occur in diabetes has also been observed in long-term galactose-fed dogs where it is reduced by the administration of aldose reductase inhibitors. Since this suggests that thyroidal changes are linked to the abnormal accumulation of sugar alcohols (polyols), present studies were conducted to confirm the presence of aldose and aldehyde reductases in dog thyroid through isolation and characterization. Aldose and aldehyde reductases were isolated from dog thyroid by a series of chromatographic steps which included gel filtration on Sephadex G-100, affinity chromatography on Matrex Gel Orange A and chromatofocusing on Mono P. A third, labile NADPH-reductase was partially purified by gel filtration on Sephadex G-100, affinity chromatography on Matrex Green A and hydroxylapatite chromatography on BIO-GEL HT. The kinetic properties of aldose and aldehyde reductases and their susceptibility to inhibition by aldose reductase inhibitors are similar to those of dog kidney aldose and aldehyde reductases. However, the levels of aldose reductase present in thyroid are extremely low compared to the levels of aldehyde reductase. A third NADPH-dependent reductase, tentatively identified as glyceraldehyde reductase, is also present in dog thyroid. This novel enzyme utilizes NADPH to reduce DL-glyceraldehyde and is clearly distinct from the other aldo-keto reductases in molecular weight, substrate specificity, inhibition by aldose reductase inhibitors and immunological properties. In summary aldose reductase, aldehyde reductase and a third novel glyceraldehyde reductase, all of which can utilize glyceraldehyde as substrate, have been identified and characterized in dog thyroid. Only aldose and aldehyde reductases, which can catalyze the production of polyols and were inhibited by aldose reductase inhibitors, appear to be linked to thyroiditis. PMID:8920636

  17. Characterization of mitochondrial thioredoxin reductase from C. elegans

    SciTech Connect

    Lacey, Brian M.; Hondal, Robert J. . E-mail: Robert.Hondal@uvm.edu

    2006-08-04

    Thioredoxin reductase catalyzes the NADPH-dependent reduction of the catalytic disulfide bond of thioredoxin. In mammals and other higher eukaryotes, thioredoxin reductases contain the rare amino acid selenocysteine at the active site. The mitochondrial enzyme from Caenorhabditis elegans, however, contains a cysteine residue in place of selenocysteine. The mitochondrial C. elegans thioredoxin reductase was cloned from an expressed sequence tag and then produced in Escherichia coli as an intein-fusion protein. The purified recombinant enzyme has a k {sub cat} of 610 min{sup -1} and a K {sub m} of 610 {mu}M using E. coli thioredoxin as substrate. The reported k {sub cat} is 25% of the k {sub cat} of the mammalian enzyme and is 43-fold higher than a cysteine mutant of mammalian thioredoxin reductase. The enzyme would reduce selenocysteine, but not hydrogen peroxide or insulin. The flanking glycine residues of the GCCG motif were mutated to serine. The mutants improved substrate binding, but decreased the catalytic rate.

  18. Isolated menthone reductase and nucleic acid molecules encoding same

    DOEpatents

    Croteau, Rodney B; Davis, Edward M; Ringer, Kerry L

    2013-04-23

    The present invention provides isolated menthone reductase proteins, isolated nucleic acid molecules encoding menthone reductase proteins, methods for expressing and isolating menthone reductase proteins, and transgenic plants expressing elevated levels of menthone reductase protein.

  19. Genetic analysis of trimethylamine N-oxide reductases in the light organ symbiont Vibrio fischeri ES114.

    PubMed

    Dunn, Anne K; Stabb, Eric V

    2008-09-01

    Trimethylamine N-oxide (TMAO) reductases are widespread in bacteria and often function in anaerobic respiration. The regulation and expression of TMAO reductase operons have been well studied in model genera such as Escherichia, Shewanella, and Rhodobacter, although TMAO reductases are present in many other bacteria, including the marine Vibrio species. The genome sequence of Vibrio fischeri revealed three putative TMAO reductase operons, and a previous report identified TMAO reductase activity in symbiotic V. fischeri isolates associated with the light organs of adult Hawaiian bobtail squid, Euprymna scolopes. We examined the roles and regulation of these three operons using mutational analyses and promoter-reporter fusions. We found that the torECA promoter, and to a lesser extent the torYZ and dmsABC promoters, were active during symbiotic colonization of juvenile E. scolopes; however, a V. fischeri strain lacking TMAO reductase activity displays no discernible colonization defect over the first 48 h. Our studies also revealed that torECA has the most active promoter of the putative TMAO reductase operons, and TorECA is the major contributor to TMAO-dependent growth in V. fischeri under the conditions tested. Interestingly, the transcriptional regulation of TMAO reductase operons in V. fischeri appears to differ from that in previously studied organisms, such as Escherichia coli, which may reflect differences in gene arrangement and bacterial habitat. This study lays the foundation for using V. fischeri as a model system for studying TMAO reductases in the Vibrionaceae. PMID:18606737

  20. Polymorphic Variants of Cytochrome P450 2B6 (CYP2B6.4–CYP2B6.9) Exhibit Altered Rates of Metabolism for Bupropion and Efavirenz: A Charge-Reversal Mutation in the K139E Variant (CYP2B6.8) Impairs Formation of a Functional Cytochrome P450-Reductase Complex

    PubMed Central

    Zhang, Haoming; Sridar, Chitra; Kenaan, Cesar; Amunugama, Hemali; Ballou, David P.

    2011-01-01

    In this study, metabolism of bupropion, efavirenz, and 7-ethoxy-4-trifluoromethylcoumarin (7-EFC) by CYP2B6 wild type (CYP2B6.1) and six polymorphic variants (CYP2B6.4 to CYP2B6.9) was investigated in a reconstituted system to gain a better understanding of the effects of the mutations on the catalytic properties of these naturally occurring variants. All six variants were successfully overexpressed in Escherichia coli, including CYP2B6.8 (the K139E variant), which previously could not be overexpressed in mammalian COS-1 cells (J Pharmacol Exp Ther 311:34–43, 2004). The steady-state turnover rates for the hydroxylation of bupropion and efavirenz and the O-deethylation of 7-EFC showed that these mutations significantly alter the catalytic activities of CYP2B6. It was found that CYP2B6.6 exhibits 4- and 27-fold increases in the Km values for the hydroxylation of bupropion and efavirenz, respectively, and CYP2B6.8 completely loses its ability to metabolize any of the substrates under normal turnover conditions. However, compared with CYP2B6.1, CYP2B6.8 retains 77% of its 7-EFC O-deethylase activity in the presence of tert-butyl hydroperoxide as an alternative oxidant, indicating that the heme and the active site are catalytically competent. Presteady-state measurements of the rate of electron transfer from NADPH-dependent cytochrome P450 reductase (CPR) to CYP2B6.8 using stopped-flow spectrophotometry revealed that CYP2B6.8 is incapable of accepting electrons from CPR. These observations provide conclusive evidence suggesting that the charge-reversal mutation in the K139E variant prevents CYP2B6.8 from forming a functional complex with CPR. Results from this work provide further insights to better understand the genotype–phenotype correlation regarding CYP2B6 polymorphisms and drug metabolism. PMID:21659470

  1. Effect of folate status and methylenetetrahydrofolate reductase genotypes on the complications and outcome of high dose methotrexate chemotherapy in north Indian children with acute lymphoblastic leukemia

    PubMed Central

    Moulik, Nirmalya Roy; Kumar, Archana; Agrawal, Suraksha; Mahdi, Abbas Ali; Kumar, Ashutosh

    2016-01-01

    Purpose: The genes of the folate metabolic pathway have been associated with toxicities during high dose methotrexate therapy for childhood ALL, however, the importance of intrinsic folate status in this regard is unclear. Methods: In the present study the effect of precourse folate levels and MTHFR genotypes on the complications during high dose methotrexate chemotherapy in children with ALL were examined. Results: Twenty-one children were studied. Folate deficiency was associated with higher incidence of neutropenia (P = 0.03) and longer duration of chemotherapy interruption (P = 0.009). Children with MTHFR1298 mutations needed more red cell transfusion (P = 0.03). All 3 deaths encountered were seen in folate deficient children. Conclusions: Folate deficiency was associated with higher complications during high dose methotrexate therapy, the implications of which are important especially in resource poor settings with high prevalence of folate deficiency. PMID:27168705

  2. Zeatin reductase in Phaseolus embryos

    SciTech Connect

    Martin, R.C.; Mok, David, W.S.; Mok, M.C. )

    1989-04-01

    Zeatin was converted to O-xylosylzeatin in embryos of Phaseolus vulgaris . O-xylosyldihydrozeatin was also identified as a zeatin metabolite. Incubation of embryo extracts with {sup 14}C-zeatin and {sup 14}C-O-xylosylzeatin revealed that reduction preceeds the O-xylosylation of zeatin. An enzyme responsible for reducing the N{sup 6}-side chain was isolated and partially purified using ammonium sulfate fractionation and affinity, gel filtration and anion exchange chromatography. The NADPH dependent reductase was zeatin specific and did not recognize cis-zeatin, ribosylzeatin, i{sup 6}Ade or i{sup 6}Ado. Two forms of the reductase could be separated by either gel filtration or anion exchange HPLC. The HMW isozyme (Mr. 55,000) eluted from the anion exchange column later than the LMW isozyme (Mr. 25,000). Interspecific differences in zeatin reductase activity were also detected.

  3. Effect of MTHFR, TGFβ1, and TNFB polymorphisms on osteoporosis in rheumatoid arthritis patients.

    PubMed

    Saad, Mohamed N; Mabrouk, Mai S; Eldeib, Ayman M; Shaker, Olfat G

    2015-09-01

    Diseases of the immune and the skeletal systems should be studied together for the deep interaction between them. Many studies consider osteoporosis (OP) as a risk factor for the prediction of disease progression in rheumatoid arthritis (RA). The aim of this research is to study the effect of four single nucleotide polymorphisms (SNPs) on RA patients with and without OP. The examined SNPs (MTHFR (C677T, and A1298C), TGFβ1 (T869C), and TNFB (A252G)) were tested by genotyping 17 RA patients with OP and 72 RA patients without OP. Associations were tested using four models (multiplicative, dominant, recessive, and co-dominant). The studied SNPs were not significantly associated with the risk of OP in RA. MTHFR, TGFβ1, and TNFB polymorphisms don't appear to be clinically useful genetic markers for predicting RA severity in Egyptian women population. PMID:25981594

  4. Associations of MTHFR Gene Polymorphisms with Hypertension and Hypertension in Pregnancy: A Meta-Analysis from 114 Studies with 15411 Cases and 21970 Controls

    PubMed Central

    Yang, Boyi; Fan, Shujun; Zhi, Xueyuan; Li, Yongfang; Liu, Yuyan; Wang, Da; He, Miao; Hou, Yongyong; Zheng, Quanmei; Sun, Guifan

    2014-01-01

    Background Several epidemiological studies have investigated the associations of methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms with hypertension (H) or hypertension in pregnancy (HIP). However, the results were controversial. We therefore performed a comprehensive meta-analysis to provide empirical evidences on the associations. Methodologies The English and Chinese databases were systematically searched to identify relevant studies. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the strength of the associations. Meta-regression, subgroup analysis, sensitivity analysis, cumulative meta-analysis and assessment of publication bias were performed in our study. Principal Findings A total of 114 studies with 15411 cases and 21970 controls were included, 111 studies with 15094 cases and 21633 controls for the C677T polymorphism and 21 with 2533 cases and 2976 controls for the A1298C polymorphism. Overall, the C677T polymorphism was significantly associated with H and HIP (H & HIP: OR = 1.26, 95% CI = 1.17–1.34; H: OR = 1.36, 95% CI = 1.20–1.53; HIP: OR = 1.21, 95% CI = 1.08–1.32). Stratified analysis by ethnicity revealed a significant association among East Asians and Caucasians, but not among Latinos, Black Africans, and Indians and Sri Lankans. In the stratified analyses according to source of controls, genotyping method, sample size and study quality, significant associations were observed in all the subgroups, with the exception of population based subgroup in H studies and large sample size and “others” genotyping method subgroups in HIP studies. For the A1298C polymorphism, no significant association was observed either in overall or subgroup analysis under all genetic models. Conclusions This meta-analysis suggests that the MTHFR C677T rather than A1298C polymorphism may be associated with H & HIP, especially among East Asians and Caucasians. PMID:24505291

  5. Engineering towards nitroreductase functionality in ene-reductase scaffolds.

    PubMed

    Park, Jonathan T; Gómez Ramos, Lizzette M; Bommarius, Andreas S

    2015-03-23

    Nitroreductases (NRs) and ene-reductases (ERs) both utilize flavin mononucleotide cofactors but catalyze distinct reactions. NRs reduce nitroaromatics, whereas ERs reduce unsaturated C=C double bonds, and these functionalities are known to somewhat overlap. Recent studies on the ER xenobiotic reductase A (XenA) from Pseudomonas putida demonstrated the possibility of increasing NR activity with active site modifications. Structural comparison between NRs and ERs led us to hypothesize that active site cavity size plays an important role in determining enzyme functionality. Residues of ER KYE1 from Kluyveromyces lactis were selected to increase the binding pocket size, compensate for hydrogen bonding pattern changes, and eliminate ER activity. Single variants were screened, and promising mutations were combined. Variant F296A/Y275A showed a 100-fold improvement in NR specific activity over wild-type, and variant H191A/F296A/Y375A exhibited complete conversion to a NR. PMID:25703443

  6. MTHFR C677T polymorphism interaction with heavy alcohol consumption increases head and neck carcinoma risk.

    PubMed

    Zhuo, Xianlu; Song, Jue; Li, Dairong; Wu, Yongzhong; Zhou, Qi

    2015-01-01

    MTHFR C677T polymorphism has been indicated to be a risk factor for cancers, but its association with head and neck cancer (HNC) risk remains inconclusive. In the present study, we aimed to get a more precise estimation by performing a quantitative meta-analysis. Published papers up to Jun 2014 was searched and screened. Necessary information was rigorously extracted for data pooling and analyzing, and then, subgroup analyses on ethnicity, source of controls, sample size, tumor type, smoking and drinking status were also carried out. As a result, twenty-three case-control studies including 14298 subjects were included. The overall data failed to reveal a significant association between MTHFR C677T polymorphism and HNC risk (homozygote comparison model: OR = 1.16; 95%CI = 0.93-1.45; dominant model: OR = 1.05; 95%CI =  .90-1.21; recessive model: OR = 1.14; 95%CI = 0.93-1.38). However, in the subgroup analysis about drinking status, increase risk was shown in the heavy drinking subgroup (TT vs CC: OR = 3.11; 95%CI = 1.52-3.02). In conclusion, the results of the present study suggest that Homozygous TT alleles of MTHFR C677T polymorphism might be a risk factor for HNC among individuals who have a heavy drinking history. Further studies are needed to get a more definitive conclusion. PMID:26035704

  7. MTHFR C677T polymorphism interaction with heavy alcohol consumption increases head and neck carcinoma risk

    PubMed Central

    Zhuo, Xianlu; Song, Jue; Li, Dairong; Wu, Yongzhong; Zhou, Qi

    2015-01-01

    MTHFR C677T polymorphism has been indicated to be a risk factor for cancers, but its association with head and neck cancer (HNC) risk remains inconclusive. In the present study, we aimed to get a more precise estimation by performing a quantitative meta-analysis. Published papers up to Jun 2014 was searched and screened. Necessary information was rigorously extracted for data pooling and analyzing, and then, subgroup analyses on ethnicity, source of controls, sample size, tumor type, smoking and drinking status were also carried out. As a result, twenty-three case-control studies including 14298 subjects were included. The overall data failed to reveal a significant association between MTHFR C677T polymorphism and HNC risk (homozygote comparison model: OR = 1.16; 95%CI = 0.93-1.45; dominant model: OR = 1.05; 95%CI = 0.90-1.21; recessive model: OR = 1.14; 95%CI = 0.93-1.38). However, in the subgroup analysis about drinking status, increase risk was shown in the heavy drinking subgroup (TT vs CC: OR = 3.11; 95%CI = 1.52-3.02). In conclusion, the results of the present study suggest that Homozygous TT alleles of MTHFR C677T polymorphism might be a risk factor for HNC among individuals who have a heavy drinking history. Further studies are needed to get a more definitive conclusion. PMID:26035704

  8. Nitrite Reductase Activity in Engineered Azurin Variants.

    PubMed

    Berry, Steven M; Strange, Jacob N; Bladholm, Erika L; Khatiwada, Balabhadra; Hedstrom, Christine G; Sauer, Alexandra M

    2016-05-01

    Nitrite reductase (NiR) activity was examined in a series of dicopper P.a. azurin variants in which a surface binding copper site was added through site-directed mutagenesis. Four variants were synthesized with copper binding motifs inspired by the catalytic type 2 copper binding sites found in the native noncoupled dinuclear copper enzymes nitrite reductase and peptidylglycine α-hydroxylating monooxygenase. The four azurin variants, denoted Az-NiR, Az-NiR3His, Az-PHM, and Az-PHM3His, maintained the azurin electron transfer copper center, with the second designed copper site located over 13 Å away and consisting of mutations Asn10His,Gln14Asp,Asn16His-azurin, Asn10His,Gln14His,Asn16His-azurin, Gln8Met,Gln14His,Asn16His-azurin, and Gln8His,Gln14His,Asn16His-azurin, respectively. UV-visible absorption spectroscopy, EPR spectroscopy, and electrochemistry of the sites demonstrate copper binding as well as interaction with small exogenous ligands. The nitrite reduction activity of the variants was determined, including the catalytic Michaelis-Menten parameters. The variants showed activity (0.34-0.59 min(-1)) that was slower than that of native NiRs but comparable to that of other model systems. There were small variations in activity of the four variants that correlated with the number of histidines in the added copper site. Catalysis was found to be reversible, with nitrite produced from NO. Reactions starting with reduced azurin variants demonstrated that electrons from both copper centers were used to reduce nitrite, although steady-state catalysis required the T2 copper center and did not require the T1 center. Finally, experiments separating rates of enzyme reduction from rates of reoxidation by nitrite demonstrated that the reaction with nitrite was rate limiting during catalysis. PMID:27055058

  9. Methylenetetrahydrofolate reductase gene C677T polymorphism and breast cancer risk: Evidence for genetic susceptibility

    PubMed Central

    Kumar, Pradeep; Yadav, Upendra; Rai, Vandana

    2015-01-01

    There are several evidences supporting the role of 5–10 methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms in breast cancer (BC). Case control association studies on breast cancer have been repeatedly performed over the last two decades, but results are inconsistent. We performed a meta-analysis to confirm the association between MTHFR C677T polymorphism and BC risk. The articles were retrieved by searching the PubMed, Google Scholar, and Springer Link databases. Crude odds ratios (OR) with 95% confidence intervals (CIs) was used to assess the strength of association between C677T polymorphism and BC. Publication bias was assessed by Egger's and Begg-Mazumdar tests. Meta-analysis was performed with Open Meta Analyst. Total 75 studies with 31,315 cases and 35, 608 controls were found suitable for the inclusion in the present meta-analysis. The results of meta-analysis suggested that there were moderate significant association between C677T polymorphism and BC risk using overall comparisons in five genetic models (T vs. C: OR = 1.08, 95% CI = 1.03–1.13, p = < 0.001; TT + CT vs. CC: OR = 1.06, 95% CI = 1.02–1.09, p = < 0.001; TT vs. CC: OR = 1.17, 95% CI = 1.06–1.28, p = 0.001; CT vs. CC OR = 1.05, 95% CI = 1.01–1.08, p = 0.005; TT vs. CT + CC: OR = 1.12, 95% CI = 1.03–1.22, p = 0.005). In conclusion, results of present meta-analysis showed modest association between MTHFR C677T polymorphism with breast cancer in total studies. However, sub-group analysis results based on ethnicity showed strong significant association between TT genotype and breast cancer (TT vs. CC; OR°=°1.26; 95% CI: 1.06–1.51; p = 0.009) in Asian population but in Caucasian population such association was not observed (TT vs. CC; OR°=°1.08; 95% CI: 0.99–1.14; p = 0.05). PMID:26629412

  10. Methylenetetrahydrofolate reductase gene C677T polymorphism and breast cancer risk: Evidence for genetic susceptibility.

    PubMed

    Kumar, Pradeep; Yadav, Upendra; Rai, Vandana

    2015-12-01

    There are several evidences supporting the role of 5-10 methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms in breast cancer (BC). Case control association studies on breast cancer have been repeatedly performed over the last two decades, but results are inconsistent. We performed a meta-analysis to confirm the association between MTHFR C677T polymorphism and BC risk. The articles were retrieved by searching the PubMed, Google Scholar, and Springer Link databases. Crude odds ratios (OR) with 95% confidence intervals (CIs) was used to assess the strength of association between C677T polymorphism and BC. Publication bias was assessed by Egger's and Begg-Mazumdar tests. Meta-analysis was performed with Open Meta Analyst. Total 75 studies with 31,315 cases and 35, 608 controls were found suitable for the inclusion in the present meta-analysis. The results of meta-analysis suggested that there were moderate significant association between C677T polymorphism and BC risk using overall comparisons in five genetic models (T vs. C: OR = 1.08, 95% CI = 1.03-1.13, p = < 0.001; TT + CT vs. CC: OR = 1.06, 95% CI = 1.02-1.09, p = < 0.001; TT vs. CC: OR = 1.17, 95% CI = 1.06-1.28, p = 0.001; CT vs. CC OR = 1.05, 95% CI = 1.01-1.08, p = 0.005; TT vs. CT + CC: OR = 1.12, 95% CI = 1.03-1.22, p = 0.005). In conclusion, results of present meta-analysis showed modest association between MTHFR C677T polymorphism with breast cancer in total studies. However, sub-group analysis results based on ethnicity showed strong significant association between TT genotype and breast cancer (TT vs. CC; OR°=°1.26; 95% CI: 1.06-1.51; p = 0.009) in Asian population but in Caucasian population such association was not observed (TT vs. CC; OR°=°1.08; 95% CI: 0.99-1.14; p = 0.05). PMID:26629412

  11. Association of methylenetetrahydrofolate reductase C677T polymorphism and serum lipid levels in the Guangxi Bai Ku Yao and Han populations

    PubMed Central

    2010-01-01

    Background The association of methylenetetrahydrofolate reductase (MTHFR) gene polymorphism and serum lipid profiles is still controversial in diverse ethnics. Bai Ku Yao is an isolated subgroup of the Yao minority in China. The aim of the present study was to eveluate the association of MTHFR C677T polymorphism and several environmental factors with serum lipid levels in the Guangxi Bai Ku Yao and Han populations. Methods A total of 780 subjects of Bai Ku Yao and 686 participants of Han Chinese were randomly selected from our previous stratified randomized cluster samples. Genotyping of the MTHFR C677T was performed by polymerase chain reaction and restriction fragment length polymorphism combined with gel electrophoresis, and then confirmed by direct sequencing. Results The levels of serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apolipoprotein (Apo) AI and ApoB were lower in Bai Ku Yao than in Han (P < 0.05-0.001). The frequency of C and T alleles was 77.4% and 22.6% in Bai Ku Yao, and 60.9% and 39.1% in Han (P < 0.001); respectively. The frequency of CC, CT and TT genotypes was 58.7%, 37.3% and 4.0% in Bai Ku Yao, and 32.6%, 56.4% and 11.0% in Han (P < 0.001); respectively. The levels of TC and LDL-C in both ethnic groups were significant differences among the three genotypes (P < 0.05-0.01). The T allele carriers had higher serum TC and LDL-C levels than the T allele noncarriers. The levels of ApoB in Han were significant differences among the three genotypes (P < 0.05). The T allele carriers had higher serum ApoB levels as compared with the T allele noncarriers. The levels of TC, TG and LDL-C in Bai Ku Yao were correlated with genotypes (P < 0.05-0.001), whereas the levels of LDL-C in Han were associated with genotypes (P < 0.001). Serum lipid parameters were also correlated with sex, age, body mass index, alcohol consumption, cigarette smoking, and blood pressure in the both ethnic groups. Conclusions The differences in serum TC, TG, LDL-C and ApoB levels between the two ethnic groups might partly result from different genotypic and allelic frequencies of the MTHFR C677T or different MTHFR gene-enviromental interactions. PMID:20977771

  12. Evaluation of Factor V G1691A, prothrombin G20210A, Factor XIII V34L, MTHFR A1298C, MTHFR C677T and PAI-1 4G/5G genotype frequencies of patients subjected to cardiovascular disease (CVD) panel in south-east region of Turkey.

    PubMed

    Oztuzcu, Serdar; Ergun, Sercan; Ula?l?, Mustafa; Nacarkahya, Glper; I?ci, Yusuf Ziya; I?ci, Mehri; Bayraktar, Recep; Tamer, Ali; akmak, Ecir Ali; Arslan, Ahmet

    2014-06-01

    Cardiovascular disease (CVD) risk factors, such as arterial hypertension, obesity, dyslipidemia or diabetes mellitus, as well as CVDs, including myocardial infarction, coronary artery disease or stroke, are the most prevalent diseases and account for the major causes of death worldwide. In the present study, 4,709 unrelated patients subjected to CVD panel in south-east part of Turkey between the years 2010 and 2013 were enrolled and DNA was isolated from the blood samples of these patients. Mutation analyses were conducted using the real-time polymerase chain reaction method to screen six common mutations (Factor V G1691A, PT G20210A, Factor XIII V34L, MTHFR A1298C and C677T and PAI-1 -675 4G/5G) found in CVD panel. The prevalence of these mutations were 0.57, 0.25, 2.61, 13.78, 9.34 and 24.27 % in homozygous form, respectively. Similarly, the mutation percent of them in heterozygous form were 7.43, 3.44, 24.91, 44.94, 41.09 and 45.66%, respectively. No mutation was detected in 92 (1.95%) patients in total. Because of the fact that this is the first study to screen six common mutations in CVD panel in south-east region of Turkey, it has a considerable value on the diagnosis and treatment of these diseases. Upon the results of the present and previous studied a careful examination for these genetic variants should be carried out in thrombophilia screening programs, particularly in Turkish population. PMID:24532105

  13. Mutation and mutation screening.

    PubMed

    Lee, L Slade; Till, Bradley J; Hill, Helen; Huynh, Owen A; Jankowicz-Cieslak, Joanna

    2014-01-01

    Molecular techniques have created the opportunity for great advances in plant mutation genetics and the science of mutation breeding. The powerful targeted induced local lesions in genomes (TILLING) technique has introduced the possibility of reverse genetics-the ability to screen for mutations at the DNA level prior to assessing phenotype. Fundamental to TILLING is the induction of mutant populations (or alternatively, the identification of mutants in the environment); and mutation induction requires an understanding and assessment of the appropriate mutagen dose required. The techniques of mutation induction, dose optimization, and TILLING are explained. PMID:24243197

  14. Human kidney aldose and aldehyde reductases.

    PubMed

    Sato, S; Kador, P F

    1993-01-01

    Mounting experimental evidence links increased aldose reductase activity with diabetes-related kidney functional changes. To investigate the interrelationship of NADPH-dependent reductases in the human kidney, both aldose reductase and aldehyde reductase were purified from human kidney by a series of chromatographic procedures, including gel filtration on Sephadex G-100, affinity chromatography on Matrex Gel Orange A, and chromatofocusing on Mono P. Each purified enzyme appeared as a single band on polyacrylamide gel after electrophoresis or isoelectric focusing. Aldose reductase has a pI of 5.7 and apparent molecular weight of 37 kDa, calculated from SDS-polyacrylamide gel electrophoresis, while aldehyde reductase has a pI of 5.2 and molecular weight of 39 kDa. Similar molecular weights were also obtained by gel filtration, indicating that both aldose and aldehyde reductases are present as monomers in the human kidney. Aldehyde reductase is primarily localized in the cortex, while the medulla contains aldose reductase. Both enzymes displayed properties consistent with the general characteristics of aldose and aldehyde reductases obtained from either rat or dog kidney. Purified aldose reductase utilizes aldose sugars such as D-xylose, D-glucose, and D-galactose as substrates while aldehyde reductase preferentially reduces D-glucuronate and oxidizes L-gulonate to D-glucuronate. Despite the lower apparent affinity of aldehyde reductase for aldose sugars (approximately 20- to 100-fold less) both enzymes reduced D-xylose, D-glucose, and D-galactose to their respective sugar alcohols in in vitro incubation studies where the generated sugar alcohols were identified by gas chromatography. Both enzymes were also inhibited by aldose reductase inhibitors.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8343612

  15. Status of Vitamins B-12 and B-6 but Not of Folate, Homocysteine, and the Methylenetetrahydrofolate Reductase C677T Polymorphism Are Associated with Impaired Cognition and Depression in Adults123

    PubMed Central

    Moorthy, Denish; Peter, Inga; Scott, Tammy M.; Parnell, Laurence D.; Lai, Chao-Qiang; Crott, Jimmy W.; Ordovás, José M.; Selhub, Jacob; Griffith, John; Rosenberg, Irwin H.; Tucker, Katherine L.; Troen, Aron M.

    2012-01-01

    The C677T polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene differs in frequency in various ethnic groups that have differing prevalence of age-related cognitive impairments. We used a series of neuro-psychological tests to examine the association of the MTHFR C677T polymorphism with cognition and depression and also to assess whether genotype modifies the association of folate and homocysteine with these outcomes. This study analyzed pooled cross-sectional data from 2 ethnically diverse cohorts of community-living adults: the Boston Puerto Rican Health Study (n = 939) and the Nutrition, Aging, and Memory in Elders study (n = 1017). Individuals in both cohorts underwent anthropometric and laboratory measurements and dietary and health assessments using validated questionnaires between the years 2003 and 2007. Cognitive outcomes included measures of global cognition [Mini-Mental Status Exam (MMSE)], depression (Center for Epidemiological Studies Depression Scale), and 3 factor scores for the domains of attention, executive function, and memory that were derived from a detailed set of neuropsychological tests. Low plasma vitamin B-12 concentrations were associated with poorer MMSE scores and higher depression scores, and low vitamin B-6 concentrations were associated with lower MMSE and worse attention and executive function in the multivariate analysis. In contrast, MTHFR genotype, folate, and homocysteine were not associated with cognition or depression in either ethnicity-pooled or stratified analysis. The current study did not find evidence of an association between the MTHFR C677T TT genotype and impaired cognition or depression in a population with adequate folate status and a high prevalence of cognitive impairment and depression. PMID:22739363

  16. Multiloculated hydrocephalus of intrauterine-onset: a case report of an unexpected MTHFR A1298C positive test result.

    PubMed

    Cizmeci, M N; Akelma, A Z; Kosehan, D; Kutukoglu, I; Sonmez, F M

    2013-01-01

    Loculated hydrocephalus is a condition in which discrete fluid-filled compartments form in association with the ventricular system of the brain. Multiloculated hydrocephalus is a subgroup of this entity involving more than one segment of the ventricular system. Abnormal descent of the cerebellar components can cause multiloculated hydrocephalus due to various pathogenesis. However, studies report no more than 10% of correlation between cerebellar herniation and hydrocephalus. We report an infant with MTHFR A1298C homozygosity, who had hydrocephalus of intrauterine-onset. Alterations in the folate metabolism might lead to congenital hydrocephalus and there is growing data on the prothrombotic effects of MTHFR polymorphisms. To the best of our knowledge, there has been no reported case of MTHFR A1298C homozygosity and intrauterine-onset multiloculated hydrocephalus as a co-existence in the literature. PMID:24341140

  17. Ribonucleotide Reductase-- a Radical Enzyme

    NASA Astrophysics Data System (ADS)

    Reichard, Peter; Ehrenberg, Anders

    1983-08-01

    Ribonucleotide reductases catalyze the enzymatic formation of deoxyribonucleotides, an obligatory step in DNA synthesis. The native form of the enzyme from Escherichia coli or from mammalian sources contains as part of its polypeptide structure a free tyrosyl radical, stabilized by an iron center. The radical participates in all probability in the catalytic process during the substitution of the hydroxyl group at C-2 of ribose by a hydrogen atom. A second, inactive form of the E. coli reductase lacks the tyrosyl radical. Extracts from E. coli contain activities that interconvert the two forms. The tyrosyl radical is introduced in the presence of oxygen, while anaerobiosis favors its removal, suggesting a regulatory role in DNA synthesis for oxygen.

  18. Nitrate reductase from Rhodopseudomonas sphaeroides.

    PubMed Central

    Kerber, N L; Cardenas, J

    1982-01-01

    The facultative phototroph Rhodopseudomonas sphaeroides DSM158 was incapable of either assimilating or dissimilating nitrate, although the organism could reduce it enzymatically to nitrite either anaerobically in the light or aerobically in the dark. Reduction of nitrate was mediated by a nitrate reductase bound to chromatophores that could be easily solubilized and functioned with chemically reduced viologens or photochemically reduced flavins as electron donors. The enzyme was solubilized, and some of its kinetic and molecular parameters were determined. It seemed to be nonadaptive, ammonia did not repress its synthesis, and its activity underwent a rapid decline when the cells entered the stationary growth phase. Studies with inhibitors and with metal antagonists indicated that molybdenum and possibly iron participate in the enzymatic reduction of nitrate. The conjectural significance of this nitrate reductase in phototrophic bacteria is discussed. PMID:6978883

  19. Perchlorate Reductase Is Distinguished by Active Site Aromatic Gate Residues.

    PubMed

    Youngblut, Matthew D; Tsai, Chi-Lin; Clark, Iain C; Carlson, Hans K; Maglaqui, Adrian P; Gau-Pan, Phonchien S; Redford, Steven A; Wong, Alan; Tainer, John A; Coates, John D

    2016-04-22

    Perchlorate is an important ion on both Earth and Mars. Perchlorate reductase (PcrAB), a specialized member of the dimethylsulfoxide reductase superfamily, catalyzes the first step of microbial perchlorate respiration, but little is known about the biochemistry, specificity, structure, and mechanism of PcrAB. Here we characterize the biophysics and phylogeny of this enzyme and report the 1.86-Å resolution PcrAB complex crystal structure. Biochemical analysis revealed a relatively high perchlorate affinity (Km = 6 μm) and a characteristic substrate inhibition compared with the highly similar respiratory nitrate reductase NarGHI, which has a relatively much lower affinity for perchlorate (Km = 1.1 mm) and no substrate inhibition. Structural analysis of oxidized and reduced PcrAB with and without the substrate analog SeO3 (2-) bound to the active site identified key residues in the positively charged and funnel-shaped substrate access tunnel that gated substrate entrance and product release while trapping transiently produced chlorate. The structures suggest gating was associated with shifts of a Phe residue between open and closed conformations plus an Asp residue carboxylate shift between monodentate and bidentate coordination to the active site molybdenum atom. Taken together, structural and mutational analyses of gate residues suggest key roles of these gate residues for substrate entrance and product release. Our combined results provide the first detailed structural insight into the mechanism of biological perchlorate reduction, a critical component of the chlorine redox cycle on Earth. PMID:26940877

  20. A novel point mutation in a 3{prime} splice site of the NADH-cytochrome b{sub 5} reductase gene results in immunologically undetectable enzyme and impaired NADH-dependent ascorbate regeneration in cultured fibroblasts of a patient with type II hereditary methemoglobinemia

    SciTech Connect

    Shirabe, Komie; Takeshita, Masazumi; Landi, M.T.

    1995-08-01

    Hereditary methemoglobinemia with generalized deficiency of NADH-cytochrome b{sub 5} reductase (b{sub 5}R) (type II) is a rare disease characterized by severe developmental abnormalities, which often lead to premature death. Although the molecular relationship between the symptoms of this condition and the enzyme deficit are not understood, it is thought that an important cause is the loss of the lipid metabolizing activities of the endoplasmic reticulum-located reductase. However, the functions of the form located on outer mitochondrial membranes have not been considered previously. In this study, we have analyzed the gene of an Italian patient and identified a novel G{r_arrow}T transversion at the splice-acceptor site of the 9th exon, which results in the complete absence of immunologically detectable b{sub 5}R in blood cells and skin fibroblasts. In cultured fibroblasts of the patient, NADH-dependent cytochrome c reductase, ferricyanide reductase, and semidehydroascorbate reductase activities were severely reduced. The latter activity is known to be due to b{sub 5}R located on outer mitochondrial membranes. Thus, our results demonstrate that the reductase in its two membrane locations, endoplasmic reticulum and outer mitochondrial membranes, is the product of the same gene and suggest that a defect in ascorbate regeneration may contribute to the phenotype of hereditary methemoglobinemia of generalized type. 37 refs., 5 figs., 2 tabs.

  1. MTHFR C677T Gene Polymorphism and Head and Neck Cancer Risk: A Meta-Analysis Based on 23 Publications

    PubMed Central

    Niu, Yu-Ming; Deng, Mo-Hong; Chen, Wen; Zeng, Xian-Tao; Luo, Jie

    2015-01-01

    Objective. Conflicting results on the association between MTHFR polymorphism and head and neck cancer (HNC) risk were reported. We therefore performed a meta-analysis to derive a more precise relationship between MTHFR C677T polymorphism and HNC risk. Methods. Three online databases of PubMed, Embase, and CNKI were researched on the associations between MTHFR C677T polymorphism and HNC risk. Twenty-three published case-control studies involving 4,955 cases and 8,805 controls were collected. Odds ratios (ORs) with 95% confidence interval (CI) were used to evaluate the relationship between MTHFR C677T polymorphism and HNC risk. Sensitivity analysis, cumulative analyses, and publication bias were conducted to validate the strength of the results. Results. Overall, no significant association between MTHFR C677T polymorphism and HNC risk was found in this meta-analysis (T versus C: OR = 1.04, 95% CI = 0.921.18; TT versus CC: OR = 1.15, 95% CI = 0.901.46; CT versus CC: OR = 1.00, 95% CI = 0.851.17; CT + TT versus CC: OR = 1.01, 95% CI = 0.871.18; TT versus CC + CT: OR = 1.11, 95% CI = 0.981.26). In the subgroup analysis by HWE, ethnicity, study design, cancer location, and negative significant associations were detected in almost all genetic models, except for few significant risks that were found in thyroid cancer. Conclusion. This meta-analysis demonstrates that MTHFR C677T polymorphism may not be a risk factor for the developing of HNC. PMID:25802478

  2. Primary ∆4-3-oxosteroid 5β-reductase deficiency: Two cases in China

    PubMed Central

    Zhao, Jing; Fang, Ling-Juan; Setchell, Kenneth DR; Chen, Rui; Li, Li-Ting; Wang, Jian-She

    2012-01-01

    Aldo-keto reductase 1D1 (AKR1D1) deficiency, a rare but life-threatening form of bile acid deficiency, has not been previously described in China. Here, we describe the first two primary ∆4-3-oxosteroid 5β-reductase deficiency patients in Mainland China diagnosed by fast atom bombardment-mass spectroscopy of urinary bile acids and confirmed by genetic analysis. A high proportion of atypical 3-oxo-∆4-bile acids in the urine indicated a deficiency in ∆4-3-oxosteroid 5β-reductase. All of the coding exons and adjacent intronic sequence of the AKR1D1 gene were sequenced using peripheral lymphocyte genomic DNA of two patients and one of the patient’s parents. One patient exhibited compound heterozygous mutations: c.396C>A and c.722A>T, while the other was heterozygous for the mutation c.797G>A. Based on these mutations, a diagnosis of primary ∆4-3-oxosteroid 5β-reductase deficiency could be confirmed. With ursodeoxycholic acid treatment and fat-soluble vitamin supplements, liver function tests normalized rapidly, and the degree of hepatomegaly was markedly reduced in both patients. PMID:23323017

  3. Polymorphisms of MTHFR C677T and A1298C association with oral carcinoma risk: a meta-analysis.

    PubMed

    Zhuo, Xianlu; Ling, Junjun; Zhou, Yan; Zhao, Houyu; Song, Yufeng; Tan, Yinghui

    2012-07-01

    Investigations regarding association of MTHFR polymorphisms with oral carcinoma risk have yielded inconclusive results. Thus, meta-analyses were performed. Results showed that no associations of C677T polymorphisms with oral carcinoma were observed for the overall data. In subgroup analyses by drinking status, homozygous TT alleles exhibited elevated oral cancer susceptibility in heavy drinkers. For A1298C polymorphism, CC alleles presented a possible preventive role for oral cancer. Collectively, results suggest that MTHFR 677TT polymorphism might be a low-penetrant risk factor for oral carcinoma only in heavy drinkers. Conversely, 1298CC alleles might play a preventive role for oral cancer. PMID:22536935

  4. Quantification of key red blood cell folates from subjects with defined MTHFR 677C>T genotypes using stable isotope dilution liquid chromatography/mass spectrometry

    PubMed Central

    Huang, Yuehua; Khartulyari, Stefanie; Morales, Megan E.; Stanislawska-Sachadyn, Anna; Von Feldt, Joan M.; Whitehead, Alexander S.; Blair, Ian A.

    2014-01-01

    Red blood cell (RBC) folate levels are established at the time of erythropoiesis and therefore provide a surrogate biomarker for the average folate status of an individual over the preceding four months. Folates are present as folylpolyglutamates, highly polar molecules that cannot be secreted from the RBCs, and must be converted into their monoglutamate forms prior to analysis. This was accomplished using an individual’s plasma pteroylpolyglutamate hydrolase by lysing the RBCs in whole blood at pH 5 in the presence of ascorbic acid. Quantitative conversion of formylated tetrahydrofolate derivatives into the stable 5,10-methenyltetrahydrofolate (5,10-MTHF) form was conducted at pH 1.5 in the presence of [13C5]-5-formyltetrahydrofolate. The resulting [13C5]-5,10-MTHF was then used as an internal standard for the formylated forms of tetrahydrofolate that had been converted into 5,10-MTHF as well any 5,10-MTHF that had been present in the original sample. A stable isotope dilution liquid chromatography-multiple reaction monitoring/mass spectrometry method was validated and then used for the accurate and precise quantification of RBC folic acid, 5-methyltetrahydrofolate (5-MTHF), tetrahydrofolate (THF), and 5,10-MTHF. The method was sensitive and robust and was used to assess the relationship between different methylenetetrahydrofolate reductase (MTHFR) 677C>T genotypes and RBC folate phenotypes. Four distinct RBC folate phenotypes could be identified. These were classified according to the relative amounts of individual RBC folates as type I (5-MTHF >95%; THF <5%; 5,10-MTHF <5%), type II (5-MTHF <95%; THF 5% to 20%; 5,10-MTHF <5%), type III (5-MTHF >55%; THF >20%; 5,10-MTHF >5%), and type IV (5-MTHF <55%; THF >20%; 5,10-MTHF >5%). PMID:18634122

  5. Genetic and epigenetic variation in the DNMT3B and MTHFR genes and colorectal adenoma risk.

    PubMed

    Ho, Vikki; Ashbury, Janet E; Taylor, Sherryl; Vanner, Stephen; King, Will D

    2016-05-01

    Polymorphisms in DNMT3B and MTHFR have been implicated in cancer etiology; however, it is increasingly clear that gene-specific DNA methylation also affects gene expression. A cross-sectional study (N = 272) investigated the main and joint effects of polymorphisms and DNA methylation in DNMT3B and MTHFR on colorectal adenoma risk. Polymorphisms examined included DNMT3B c.-6-1045G > T, and MTHFR c.665C > T and c.1286A > C. DNA methylation of 66 and 28 CpG sites in DNMT3B and MTHFR, respectively, was quantified in blood leukocytes using Sequenom EpiTYPER®. DNA methylation was conceptualized using two approaches: (1) average methylation and (2) unsupervised principal component analysis to identify variables that represented methylation around the transcription start site and the gene coding area of both genes. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) associated with the main and joint effects of polymorphisms and DNA methylation. DNA methyltransferase 3B (DNMT3B) TT versus GG/GT genotypes was associated with increased colorectal adenoma risk (OR = 2.12; 95% CI: 1.03-4.34). In addition, increasing DNA methylation in the gene-coding area of DNMT3B was associated with higher risk of colorectal adenomas (OR = 1.34; 95% CI: 1.01-1.79 per SD). In joint effect analyses, synergistic effects were observed among those with both the DNMT3B TT genotype and higher DNMT3B methylation levels compared to those with GT/GG genotypes and lower methylation levels (OR = 4.19; 95% CI: 1.45-12.13 for average methylation; OR = 4.26; 95%CI: 1.31-13.87 for methylation in the transcription start site). This research provides novel evidence that genetic and epigenetic variations contribute to colorectal adenoma risk, precursor to the majority of colorectal cancer (CRC). Environ. Mol. Mutagen. 57:261-268, 2016. © 2016 Wiley Periodicals, Inc. PMID:27062459

  6. Inheritance of nitrite reductase and regulation of nitrate reductase, nitrite reductase, and glutamine synthetase isozymes.

    PubMed Central

    Heath-Pagliuso, S; Huffaker, R C; Allard, R W

    1984-01-01

    Banding patterns of nitrate reductase (NR), nitrite reductase (NiR), and glutamine synthetase (GS) from leaves of diploid barley (Hordeum vulgare), tetraploid wheat (Triticum durum), hexaploid wheat (Triticum aestivum), and tetraploid wild oats (Avena barbata) were compared following starch gel electrophoresis. Two NR isozymes, which appeared to be under different regulatory control, were observed in each of the three species. The activity of the more slowly migrating nitrate reductase isozyme (NR1) was induced by NO3- in green seedlings and cycloheximide inhibited induction. However, the activity of the faster NR isozyme (NR2) was unaffected by addition of KNO3, and it was not affected by treatments of cycloheximide or chloramphenicol. Only a single isozyme of nitrite reductase was detected in surveys of three tetraploid and 18 hexaploid wheat, and 48 barley accessions; however, three isozymes associated with different ecotypes were detected in the wild oats. Inheritance patterns showed that two of the wild oat isozymes were governed by a single Mendelian locus with two codominant alleles; however, no variation was detected for the third isozyme. Treatment of excised barely and wild oat seedlings with cycloheximide and chloramphenicol showed that induction of NiR activity was greatly inhibited by cycloheximide, but only slightly by chloramphenicol. Only a single GS isozyme was detected in extracts of green leaves of wheat, barley, and wild oat seedlings. No electrophoretic variation was observed within or among any of these three species. Thus, this enzyme appears to be the most structurally conserved of the three enzymes. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:11541965

  7. Fatty acyl-CoA reductase

    SciTech Connect

    Reiser, Steven E.; Somerville, Chris R.

    1998-12-01

    The present invention relates to bacterial enzymes, in particular to an acyl-CoA reductase and a gene encoding an acyl-CoA reductase, the amino acid and nucleic acid sequences corresponding to the reductase polypeptide and gene, respectively, and to methods of obtaining such enzymes, amino acid sequences and nucleic acid sequences. The invention also relates to the use of such sequences to provide transgenic host cells capable of producing fatty alcohols and fatty aldehydes.

  8. The prenyltransferase UBIAD1 is the target of geranylgeraniol in degradation of HMG CoA reductase.

    PubMed

    Schumacher, Marc M; Elsabrouty, Rania; Seemann, Joachim; Jo, Youngah; DeBose-Boyd, Russell A

    2015-01-01

    Schnyder corneal dystrophy (SCD) is an autosomal dominant disorder in humans characterized by abnormal accumulation of cholesterol in the cornea. SCD-associated mutations have been identified in the gene encoding UBIAD1, a prenyltransferase that synthesizes vitamin K2. Here, we show that sterols stimulate binding of UBIAD1 to the cholesterol biosynthetic enzyme HMG CoA reductase, which is subject to sterol-accelerated, endoplasmic reticulum (ER)-associated degradation augmented by the nonsterol isoprenoid geranylgeraniol through an unknown mechanism. Geranylgeraniol inhibits binding of UBIAD1 to reductase, allowing its degradation and promoting transport of UBIAD1 from the ER to the Golgi. CRISPR-CAS9-mediated knockout of UBIAD1 relieves the geranylgeraniol requirement for reductase degradation. SCD-associated mutations in UBIAD1 block its displacement from reductase in the presence of geranylgeraniol, thereby preventing degradation of reductase. The current results identify UBIAD1 as the elusive target of geranylgeraniol in reductase degradation, the inhibition of which may contribute to accumulation of cholesterol in SCD. PMID:25742604

  9. Creatine kinase MM TaqI and methylenetetrahydrofolate reductase C677T and A1298C gene polymorphisms influence exercise-induced C-reactive protein levels.

    PubMed

    Miranda-Vilela, Ana Luisa; Akimoto, Arthur K; Lordelo, Graciana S; Pereira, Luiz C S; Grisolia, Cesar K; Klautau-Guimarães, Maria de Nazaré

    2012-03-01

    Physical training induces beneficial adaptations, but exhausting exercise increases reactive oxygen species, which can cause muscular injuries with consequent inflammatory processes, implying jeopardized performance and possibly overtraining. Acute strenuous exercise almost certainly exceeds the benefits of physical activity; it can compromise performance and may contribute to increased future risk of cardiovascular disease (CVD) in athletes. Polymorphisms in the muscle-type creatine kinase (CK-MM) gene may influence performance and adaptation to training, while many potentially significant genetic variants are reported as risk factors for CVD. Therefore, we investigated the influence of polymorphisms in CK-MM TaqI and NcoI, methylenetetrahydrofolate reductase (MTHFR C677T and A1298C) and C-reactive protein (CRP G1059C) genes on exercise-induced damage and inflammation markers. Blood samples were taken immediately after a race (of at least 4 km) that took place outdoors on flat tracks, and were submitted to genotyping and biochemical evaluation of aspartate aminotransferase (AST), CK, CRP and high-sensitivity CRP (hs-CRP). CK-MM TaqI polymorphism significantly influenced results of AST, CK and hs-CRP, and an association between MTHFR C677T and A1298C with CRP level was found, although these levels did not exceed reference values. The results indicate that these polymorphisms can indirectly influence performance, contribute to higher susceptibility to exercise-induced inflammation or protection against it, and perhaps affect future risks of CVD in athletes. PMID:21706313

  10. Creatine kinase MM TaqI and methylenetetrahydrofolate reductase C677T and A1298C gene polymorphisms influence exercise-induced C-reactive protein levels.

    PubMed

    Miranda-Vilela, Ana Luisa; Akimoto, Arthur K; Lordelo, Graciana S; Pereira, Luiz C S; Grisolia, Cesar K; Klautau-Guimarães, Maria de Nazaré

    2012-01-01

    Physical training induces beneficial adaptations, but exhausting exercise increases reactive oxygen species, which can cause muscular injuries with consequent inflammatory processes, implying jeopardized performance and possibly overtraining. Acute strenuous exercise almost certainly exceeds the benefits of physical activity; it can compromise performance and may contribute to increased future risk of cardiovascular disease (CVD) in athletes. Polymorphisms in the muscle-type creatine kinase (CK-MM) gene may influence performance and adaptation to training, while many potentially significant genetic variants are reported as risk factors for CVD. Therefore, we investigated the influence of polymorphisms in CK-MM TaqI and NcoI, methylenetetrahydrofolate reductase (MTHFR C677T and A1298C) and C-reactive protein (CRP G1059C) genes on exercise-induced damage and inflammation markers. Blood samples were taken immediately after a race (of at least 4 km) that took place outdoors on flat tracks, and were submitted to genotyping and biochemical evaluation of aspartate aminotransferase (AST), CK, CRP and high-sensitivity CRP (hs-CRP). CK-MM TaqI polymorphism significantly influenced results of AST, CK and hs-CRP, and an association between MTHFR C677T and A1298C with CRP level was found, although these levels did not exceed reference values. Results indicate that these polymorphisms can indirectly influence performance, contribute to higher susceptibility to exercise-induced inflammation or protection against it, and perhaps affect future risks of CVD in athletes. PMID:21516340

  11. Association of the rs1801133 variant in the MTHFR gene and sporadic Parkinson's disease.

    PubMed

    García, S; Coral-Vázquez, Rm; Gallegos-Arreola, M P; Montes-Almanza, L A; Canto, P; García-Martínez, F A; Chavira-Hernández, G; Palma-Flores, C; Dávila-Maldonado, L; Cuevas-García, C F; López Hernández, L B

    2015-01-01

    The MTHFR gene has been reported as a susceptibility locus for sporadic Parkinson's disease (sPD). The functional variant rs1801133 has been linked to hyperhomocysteinemia and dopaminergic cell death. Among different populations, Mexican-Mestizos (most present-day Mexicans) have the highest frequency of this variant. Therefore, we sought to determine a possible association of rs1801133 with SPD. In total, 356 individuals were included: 140 patients with PD, diagnosed according to the Queen Square Brain Bank criteria, and 216 neurologically healthy controls. Genotyping was performed using TaqMan probes for rs1801133 and real-time PCR. Logistic regression analysis with adjustment for smoking and gender was used to test for an association between genotype and SPD. The CC genotype was associated with SPD; exp() = 2.06; 95% CI: 1.101-3.873, p = 0.024. No association with age at onset, cognitive impairment or gender was found in our study group. Our data suggest an important role of MTHFR gene variants in SPD. PMID:25909872

  12. A case of recurrent pancytopenia in a patient with acute promyelocytic leukemia on maintenance chemotherapy and concomitant methyltetrahydrofolate reductase and thiopurine S-methyltransferase mutation - review of literature.

    PubMed

    Keung, Yi-Kong; Keung, Lap-Woon; Hong-Lung Hu, Eddie

    2016-06-01

    Pharmacogenetics is a study of how genetic variation of an individual affects the drug response. We report a case of recurrent pancytopenia resulting from maintenance chemotherapy in a patient with acute promyelocytic leukemia and two pharmacogenetic mutations, namely, methylene tetrahydrofolate reductase C677T homozygous mutation and thiopurine methyltransferase mutation. PMID:25791511

  13. Dihydropteridine reductase from Escherichia coli.

    PubMed Central

    Vasudevan, S G; Shaw, D C; Armarego, W L

    1988-01-01

    A dihydropteridine reductase from Escherichia coli was purified to apparent homogeneity. It is a dimeric enzyme with identical subunits (Mr 27000) and a free N-terminal group. It can use NADH (Vmax./Km 3.36 s-1) and NADPH (Vmax./Km 1.07 s-1) when 6-methyldihydro-(6H)-pterin is the second substrate, as well as quinonoid dihydro-(6H)-biopterin (Vmax./Km 0.69 s-1), dihydro-(6H)-neopterin (Vmax./Km 0.58 s-1), dihydro-(6H)-monapterin 0.66 s-1), 6-methyldihydro-(6H)-pterin and cis-6,7-dimethyldihydro-(6H)-pterin (Vmax./Km 0.66 s-1) when NADH is the second substrate. The pure reductase has a yellow colour and contains bound FAD. The enzyme also has pterin-independent NADH and NADPH oxidoreductase activities when potassium ferricyanide is the electron acceptor. Images Fig. 2. PMID:3060113

  14. MTHFR C677T polymorphism and differential methylation status in gastric cancer: an association with Helicobacter pylori infection.

    PubMed

    Neves Filho, Eduardo Henrique Cunha; Alves, Markenia Kelia Santos; Lima, Valeska Portela; Rabenhorst, Silvia Helena Barem

    2010-12-01

    MTHFR C677T and Helicobacter pylori infection are believed to play critical roles in the DNA methylation process, an epigenetic feature frequently found in gastric cancer. The aim of this study was to verify the associations between the MTHFR C677T polymorphism and the methylation status of three gastric cancer-related genes. The influence of H. pylori strains was also assessed. DNA extracted from 71 gastric tumor samples was available for MTHFR C677T genotyping by PCR-RFLP, promoter methylation identification by MS-PCR and H. pylori detection and posterior subtyping (cagA and vacA genes) by PCR. In the distal tumors, a positive correlation was found between the methylation of CDKN2A and the allele T carriers (r=0.357; p=0.009). Considering the eldest patients (age ?60 years old), this correlation was even higher (r=0,417; p=0.014). H. pylori infection by highly pathogenic strains (cagA+/vacAs1m1) was also found correlated to promoter methylation of CDKN2A and the allele T carriers in distal tumors (r=0.484; p=0.026). No significant correlation was verified between MTHFR C677T genotype and promoter methylation status when we analyzed the general sample. DNA methylation in CDKN2A associated to the MTHFR 677T carrier is suggested to be a distal tumor characteristic, especially in those 60 years old or older, and it seems to depend on the infection by H. pylori cagA/vacAs1m1 strains. PMID:20957490

  15. Association between the MTHFR A1298C polymorphism and risk of cancer: evidence from 265 case-control studies.

    PubMed

    Zhu, Xin-Li; Liu, Zhi-Zhong; Yan, Sen-Xiang; Wang, Wei; Chang, Rui-Xia; Zhang, Chun-Yan; Guo, Yan

    2016-02-01

    Many molecular, epidemiological studies have been performed to explore the association between MTHFR A1298C polymorphism and cancer risk. However, the results were inconsistent or even contradictory. Hence, we performed a meta-analysis to investigate the association between cancer risk and MTHFR A1298C (81,040 cases and 114,975 controls from 265 studies) polymorphism. Overall, significant association was observed between MTHFR A1298C polymorphism and cancer risk when all eligible studies were pooled into the meta-analysis. In further stratified and sensitivity analyses, significantly increased cervical cancer (dominant model: OR 1.46, 95 % CI 1.13-1.90; AC vs. AA: OR 1.48, 95 % CI 1.13-1.92) and lymphoma (dominant model: OR 1.22, 95 % CI 1.04-1.44; recessive model: OR 1.66, 95 % CI 1.15-2.39; CC vs. AA: OR 1.75, 95 % CI 1.21-2.53) risk were observed in Asians, and significantly decreased colorectal cancer risk was found in Asians (recessive model: OR 0.75, 95 % CI 0.59-0.96; CC vs. AA: OR 0.77, 95 % CI 0.60-1.00). In summary, this meta-analysis suggests that MTHFR A1298C polymorphism is associated with increased cervical cancer and lymphoma risk in Asians, and MTHFR A1298C polymorphism is associated with decreased colorectal cancer risk in Asians. Moreover, this meta-analysis also points out the importance of new studies, such as oral cancer and chronic myeloid leukemia, because they had high heterogeneity in this meta-analysis (I (2) > 75 %). PMID:26156333

  16. The biochemical structure and function of methylenetetrahydrofolate reductase provide the rationale to interpret the epidemiological results on the risk for infants with Down syndrome.

    PubMed

    Martnez-Fras, M L

    2008-06-01

    Studies on the structure of the methylenetetrahydrofolate reductase (MTHFR) gene and the mechanisms by which folate may reduce homocysteine levels in bacteria and in humans have provided a rationale to understand the conflicting epidemiological observations between the studies on the 677C-T and 1298A-C MTHFR polymorphic variants, and the risk of having an infant with Down syndrome (DS). However, three of the combined genotypes (CTCC, TTAC, and TTCC) are very infrequent in the human population. In fact, these three rare genotypes were only observed in two of the eight epidemiological studies that analyzed these genotype combinations and the risk of DS. In a study of the Indian population these three genotypes were identified in mothers of DS children but not in control mothers demonstrating a statistically significant increase in the risk of giving birth to DS infants. Conversely, the CTCC and TTAC genotypes were only observed in control mothers and not in mothers of DS infants in the Spanish study, while the TTCC genotype was not observed in any Spanish mother analyzed. These results were not related to the frequency of the T allele, since this was lower in the Indian population (21.4% among case mothers and 12.4% in control mothers) than in the Spanish population (33.9%). At present, several important biological aspects on the Hcy cycle are known, including: (a) the biochemical structure and function of the MTHFR enzyme, (b) the biological basis for the effect of the different 677C-T and 1298A-C MTHFR genotype combinations on Hcy levels, (c) that folate is not synthesized by the organism that obtained it from the diet, (d) that TT homozygotes will be at particular risk when their folate status is low because the mutant enzyme requires much higher levels of folate than the physiological one to stabilize the binding of flavin-adenosine-dinucleotide (FAD), (e) that the release of flavin is prevented by increasing the levels of folate, and (f) that the cystathionine-beta-synthase gene is located on chromosome 21. Together, these facts suggest that destabilization of the Hcy cycle in function of the levels of S-adenosylmethionine (SAM), may be modified by some embryonic and maternal genotypes, as well as by maternal nutritional status and life style. This may also influence the probability that some embryos survive to birth, but in different way for those with and without trisomy 21, as is discussed in this article. PMID:18446861

  17. Role of Aldo-Keto Reductase Family 1 (AKR1) Enzymes in Human Steroid Metabolism

    PubMed Central

    Rižner, Tea Lanišnik; Penning, Trevor M.

    2013-01-01

    Human aldo-keto reductases AKR1C1-AKR1C4 and AKR1D1 play essential roles in the metabolism of all steroid hormones, the biosynthesis of neurosteroids and bile acids, the metabolism of conjugated steroids, and synthetic therapeutic steroids. These enzymes catalyze NADPH dependent reductions at the C3, C5, C17 and C20 positions on the steroid nucleus and side-chain. AKR1C1-AKR1C4 act as 3-keto, 17-keto and 20-ketosteroid reductases to varying extents, while AKR1D1 acts as the sole Δ4-3-ketosteroid-5β-reductase (steroid 5β-reductase) in humans. AKR1 enzymes control the concentrations of active ligands for nuclear receptors and control their ligand occupancy and trans-activation, they also regulate the amount of neurosteroids that can modulate the activity of GABAA and NMDA receptors. As such they are involved in the pre-receptor regulation of nuclear and membrane bound receptors. Altered expression of individual AKR1C genes is related to development of prostate, breast, and endometrial cancer. Mutations in AKR1C1 and AKR1C4 are responsible for sexual development dysgenesis and mutations in AKR1D1 are causative in bile-acid deficiency. PMID:24189185

  18. Identification of the Arabidopsis CHL3 gene as the nitrate reductase structural gene NIA2.

    PubMed Central

    Wilkinson, J Q; Crawford, N M

    1991-01-01

    Chlorate, the chlorine analog of nitrate, is a herbicide that has been used to select mutants impaired in the process of nitrate assimilation. In Arabidopsis thaliana, mutations at any one of eight distinct loci confer resistance to chlorate. The molecular identities of the genes at these loci are not known; however, one of these loci--chl3--maps very near the nitrate reductase structural gene NIA2. Through the isolation, characterization, and genetic analysis of new chlorate-resistant mutants generated by gamma irradiation, we have been able to demonstrate that the CHL3 gene and the NIA2 gene are identical. Three new chlorate-resistant mutants were identified that had deletions of the entire NIA2 gene. These nia2 null mutants were viable and still retained 10% of wild-type nitrate reductase activity in the leaves of the plants. All three deletion mutations were found to be new alleles of chl3. Introduction of the NIA2 gene back into these chl3 mutants by Agrobacterium-mediated transformation partially complemented their mutant phenotype. From these data, we conclude that Arabidopsis has at least two functional nitrate reductase genes and that the NIA2 gene product accounts for the majority of the leaf nitrate reductase activity and chlorate sensitivity of Arabidopsis plants. PMID:1840922

  19. Correlation of methylenetetrahydrofolate reductase polymorphisms with homocysteine metabolism in healthy Lebanese adults.

    PubMed

    Mahfouz, Rami A; Cortas, Najwa K; Charafeddine, Khalil M; Abdul Khalik, Rabab N; Sarieddine, Doja S; Kadi, Raneem H; Daher, Rose T

    2012-08-10

    Hyperhomocysteinemia is associated with several vascular and teratogenic conditions. Determinants of total homocysteine concentrations include genetic and nutritional factors. This study assesses the relation between homocysteine concentrations and MTHFR gene polymorphisms at two common alleles (C677T (rs1801133) and A1298C (rs1801131)) as well as other predictors of homocysteine (folate, vitamin B(12), body mass index (BMI), age, and gender) in a group of healthy Lebanese: 109 males and 124 females aged 17-55years. We used serum for the determination of homocysteine, folate and vitamin B(12) levels and blood drawn in EDTA tubes for molecular analysis of MTHFR polymorphisms. Hyperhomocysteinemia was present in 59/233 (25.3%) of the subjects, with male/female ratio of 1.95. Multivariable regression analysis showed that homocysteine levels were negatively related to folate and vitamin B(12) and positively related to male gender and C677T homozygosity; but not A1298C polymorphism, BMI or age. The prevalence of wild, heterozygous, and homozygous C677T genotypes was 45.0%, 43.3% and 11.6%, respectively; with a carrier frequency of 54.9% and allelic frequency of 33.3%. The A1298C genotypic prevalence was 39.5%, 30.9%, and 29.6% respectively; with a carrier frequency of 60.5% and allelic frequency of 45.1%. C677T/A1289C compound heterozygosity was present in 47/233 (20.2%) of volunteers. In this first pilot study, gender, folate, vitamin B(12) and C677T mutational status could explain around 32% of homocysteine variations. Future larger studies are recommended to investigate other predictors of homocysteine variation and combine them with markers explored in this and other studies, in order to evaluate their impact on vascular and/or congenital diseases. PMID:22652272

  20. Common folate gene variant, MTHFR C677T, is associated with brain structure in two independent cohorts of people with mild cognitive impairment☆

    PubMed Central

    Rajagopalan, Priya; Jahanshad, Neda; Stein, Jason L.; Hua, Xue; Madsen, Sarah K.; Kohannim, Omid; Hibar, Derrek P.; Toga, Arthur W.; Jack, Clifford R.; Saykin, Andrew J.; Green, Robert C.; Weiner, Michael W.; Bis, Joshua C.; Kuller, Lewis H.; Riverol, Mario; Becker, James T.; Lopez, Oscar L.; Thompson, Paul M.

    2012-01-01

    A commonly carried C677T polymorphism in a folate-related gene, MTHFR, is associated with higher plasma homocysteine, a well-known mediator of neuronal damage and brain atrophy. As homocysteine promotes brain atrophy, we set out to discover whether people carrying the C677T MTHFR polymorphism which increases homocysteine, might also show systematic differences in brain structure. Using tensor-based morphometry, we tested this association in 359 elderly Caucasian subjects with mild cognitive impairment (MCI) (mean age: 75 ± 7.1 years) scanned with brain MRI and genotyped as part of Alzheimer's Disease Neuroimaging Initiative. We carried out a replication study in an independent, non-overlapping sample of 51 elderly Caucasian subjects with MCI (mean age: 76 ± 5.5 years), scanned with brain MRI and genotyped for MTHFR, as part of the Cardiovascular Health Study. At each voxel in the brain, we tested to see where regional volume differences were associated with carrying one or more MTHFR ‘T’ alleles. In ADNI subjects, carriers of the MTHFR risk allele had detectable brain volume deficits, in the white matter, of up to 2–8% per risk T allele locally at baseline and showed accelerated brain atrophy of 0.5–1.5% per T allele at 1 year follow-up, after adjusting for age and sex. We replicated these brain volume deficits of up to 5–12% per MTHFR T allele in the independent cohort of CHS subjects. As expected, the associations weakened after controlling for homocysteine levels, which the risk gene affects. The MTHFR risk variant may thus promote brain atrophy by elevating homocysteine levels. This study aims to investigate the spatially detailed effects of this MTHFR polymorphism on brain structure in 3D, pointing to a causal pathway that may promote homocysteine-mediated brain atrophy in elderly people with MCI. PMID:24179750

  1. The Frequency of Some Thrombophilic Mutations in Eastern Turkey

    PubMed Central

    Ozturk, Nurinnisa; Bakan, Ebubekir; Gul, Mehmet Ali; Bakan, Nuri; Sebin, Engin; Kiziltunc, Ahmet

    2016-01-01

    Objective: Factor V / Factor II / Methylenetetrahydrofolate reductase, gene polymorphisms are closely associated with thrombophilia. Regional frequencies of these mutations may show a characteristic state. The aim of our study was to evaluate the frequency of commonly seen Factor V / Factor II / Methylenetetrahydrofolate reductase gene polymorphisms in Eastern Turkey. Materials and Methods: In 433 patients sent to the laboratory with the suspicion of thrombophilia, using whole blood samples, an automated Nucleic Acid Test was used for mutation determinations in Verigene System. The kit module was designed to detect the Factor V G1691A / Factor II G20210A / Methylenetetrahydrofolate reductase gene C677T single nucleotide polymorphisms. Results: In 433 patients, 8.7% for Factor V G1691A polymorphisms were heterozygous genotype, 3.9% for Factor II G20210A polymorphisms were heterozygous genotype, and 43.9% for methylenetetrahydrofolate reductase 677C>T polymorphisms were heterozygous genotype and 3.0% homozygous mutation genotype. Conclusion: Detection of these commonly seen Factor V / Factor II / Methylenetetrahydrofolate reductase single nucleotide polymorphisms can help to identify patients in high risk group and to evaluate the interaction of genetic and acquired risk factors. Our findings suggest that commonly seen thrombophilic allele mutation frequency in our region is the same as the data reported in the literature. PMID:27026755

  2. Phenotypic classification of male pseudohermaphroditism due to steroid 5{alpha}-reductase 2 deficiency

    SciTech Connect

    Sinnecker, G.H.G; Hiort, O.; Kruse, K.; Dibbelt, L.

    1996-05-03

    Conversion of testosterone (T) to dihydrotestosterone (DHT) in genital tissue is catalysed by the enzyme 5{alpha}-reductase 2, which is encoded by the SRD5A2 gene. The potent androgen DHT is required for full masculinization of the external genitalia. Mutations of the SRD5A2 gene inhibit enzyme activity, diminish DHT formation, and hence cause masculinization defects of varying degree. The classical syndrome, formerly described as pseudovaginal perineoscrotal hypospadias, is characterized by a predominantly female phenotype at birth and significant virilization without gynecomastia at puberty. We investigated nine patients with steroid 5{alpha}-reductase 2 deficiency (SRD). T/DHT-ratios were highly increased in the classical syndrome, but variable in the less severe affected patients. Mutations in the SRD5A2 gene had been characterized using PCR-SSCP analysis and direct DNA sequencing. A small deletion was encountered in two patients, while all other patients had single base mutations which result in amino acid substitutions. We conclude that phenotypes may vary widely in patients with SRD5A2 gene mutations spanning the whole range from completely female to normal male without distinctive clinical signs of the disease. Hence, steroid 5{alpha}-reductase deficiency should be considered not only in sex reversed patients with female or ambiguous phenotypes, but also in those with mild symptoms of undermasculinization as encountered in patients with hypospadias and/or micropenis. A classification based on the severity of the masculinization defect may be used for correlation of phenotypes with enzyme activities and genotypes, and for comparisons of phenotypes between different patients as the basis for clinical decisions to be made in patients with pseudohermaphroditism due to steroid 5{alpha}-reductase 2 deficiency. 22 refs., 2 figs., 2 tabs.

  3. Tetrathionate reductase of Salmonella thyphimurium: a molybdenum containing enzyme

    SciTech Connect

    Hinojosa-Leon, M.; Dubourdieu, M.; Sanchez-Crispin, J.A.; Chippaux, M.

    1986-04-29

    Use of radioactive molybdenum demonstrates that the tetrathionate reductase of Salmonella typhimurium is a molydenum containing enzyme. It is proposed that this enzyme shares with other molybdo-proteins, such as nitrate reductase, a common molybdenum containing cofactor the defect of which leads to the loss of the tetrathionate reductase and nitrate reductase activities.

  4. Reduction of drug ketones by dihydrodiol dehydrogenases, carbonyl reductase and aldehyde reductase of human liver.

    PubMed

    Ohara, H; Miyabe, Y; Deyashiki, Y; Matsuura, K; Hara, A

    1995-07-17

    In this study, we compared the enzymatic reduction of 10 drugs with a ketone group by homogeneous carbonyl reductase, aldehyde reductase and three dihydrodiol dehydrogenases of human liver cytosol. At least one and in some cases all of the three dihydrodiol dehydrogenases reduced each of the ten drugs. Among these naloxone, naltrexone, befunolol, ethacrynic acid and ketoprofen were substrates specific for the dehydrogenases. The other drugs--haloperidol, metyrapone, loxoprofen, daunorubicin and acetohexamide--were highly reduced by carbonyl reductase and/or aldehyde reductase. The dihydrodiol dehydrogenases also showed lower Km values for haloperidol and loxoprofen than did carbonyl reductase. The results indicate that the three dihydrodiol dehydrogenases, as well as the two reductases, are implicated in the reduction of ketone-containing drugs in human liver cytosol. PMID:7632166

  5. Imine Reductases: A Comparison of Glutamate Dehydrogenase to Ketimine Reductases in the Brain

    PubMed Central

    Jamie, Joanne F.; Cooper, Arthur J. L.

    2013-01-01

    A key intermediate in the glutamate dehydrogenase (GDH)-catalyzed reaction is an imine. Mechanistically, therefore, GDH exhibits similarities to the ketimine reductases. In the current review, we briefly discuss (a) the metabolic importance of the GDH reaction in liver and brain, (b) the mechanistic similarities between GDH and the ketimine reductases, (c) the metabolic importance of the brain ketimine reductases, and (d) the neurochemical consequences of defective ketimine reductases. Our review contains many historical references to the early work on amino acid metabolism. This work tends to be overlooked nowadays, but is crucial for a contemporary understanding of the central importance of ketimines in nitrogen and intermediary metabolism. The ketimine reductases are important enzymes linking nitrogen flow among several key amino acids, yet have been little studied. The cerebral importance of the ketimine reductases is an area of biomedical research that deserves far more attention. PMID:23314864

  6. Evolution Alters the Enzymatic Reaction Coordinate of Dihydrofolate Reductase

    PubMed Central

    2015-01-01

    How evolution has affected enzyme function is a topic of great interest in the field of biophysical chemistry. Evolutionary changes from Escherichia coli dihydrofolate reductase (ecDHFR) to human dihydrofolate reductase (hsDHFR) have resulted in increased catalytic efficiency and an altered dynamic landscape in the human enzyme. Here, we show that a subpicosecond protein motion is dynamically coupled to hydride transfer catalyzed by hsDHFR but not ecDHFR. This motion propagates through residues that correspond to mutational events along the evolutionary path from ecDHFR to hsDHFR. We observe an increase in the variability of the transition states, reactive conformations, and times of barrier crossing in the human system. In the hsDHFR active site, we detect structural changes that have enabled the coupling of fast protein dynamics to the reaction coordinate. These results indicate a shift in the DHFR family to a form of catalysis that incorporates rapid protein dynamics and a concomitant shift to a more flexible path through reactive phase space. PMID:25369552

  7. Purification and properties of aldose reductase and aldehyde reductase from EHS tumor cells.

    PubMed

    Tanimoto, T; Sato, S; Kador, P F

    1990-02-01

    Engelbreth-Holm-Swarm (EHS) tumor cells were utilized as a model for investigating the production of basement membrane components. These cells contain two immunologically distinct NADPH-dependent reductases, aldose reductase (EC 1.1.1.21) and aldehyde reductase (EC 1.1.1.2), which were purified to apparent homogeneity by a combination of procedures which included ammonium sulfate fractionation, Sephadex G-75 gel filtration, Matrex Gel Orange A affinity chromatography, and chromatofocusing on Pharmacia Mono P. The molecular weights of aldose and aldehyde reductases were estimated to be 38K and 40K, respectively, by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Substrate specificity studies showed that both enzymes were capable of reducing a variety of aldehydes to their respective alcohols; however, only aldehyde reductase oxidized L-gulonic acid. Surprisingly, both enzymes showed similar reactivities with D-glucose and D-galactose, suggesting that both aldose and aldehyde reductases may contribute to sorbitol production in the EHS tumor cell. The activities of both enzymes were increased by the presence of sulfate ion, but chloride ion decreased the activity of aldose reductase. Both aldose and aldehyde reductases were inhibited by a series of structurally diverse aldose reductase inhibitors. PMID:2106320

  8. Genetics Home Reference: sepiapterin reductase deficiency

    MedlinePlus

    ... SEPIAPTERIN REDUCTASE DEFICIENCY Sources for This Page Abeling NG, Duran M, Bakker HD, Stroomer L, Thöny B, ... MM, Willemsen MA, Wevers RA, Lagerwerf AJ, Abeling NG, Blau N, Thöny B, Vargiami E, Zafeiriou DI. ...

  9. Divergent evolution of protein conformational dynamics in dihydrofolate reductase.

    PubMed

    Bhabha, Gira; Ekiert, Damian C; Jennewein, Madeleine; Zmasek, Christian M; Tuttle, Lisa M; Kroon, Gerard; Dyson, H Jane; Godzik, Adam; Wilson, Ian A; Wright, Peter E

    2013-11-01

    Molecular evolution is driven by mutations, which may affect the fitness of an organism and are then subject to natural selection or genetic drift. Analysis of primary protein sequences and tertiary structures has yielded valuable insights into the evolution of protein function, but little is known about the evolution of functional mechanisms, protein dynamics and conformational plasticity essential for activity. We characterized the atomic-level motions across divergent members of the dihydrofolate reductase (DHFR) family. Despite structural similarity, Escherichia coli and human DHFRs use different dynamic mechanisms to perform the same function, and human DHFR cannot complement DHFR-deficient E. coli cells. Identification of the primary-sequence determinants of flexibility in DHFRs from several species allowed us to propose a likely scenario for the evolution of functionally important DHFR dynamics following a pattern of divergent evolution that is tuned by cellular environment. PMID:24077226

  10. Structure of a bacterial homologue of vitamin K epoxide reductase

    SciTech Connect

    Li, Weikai; Schulman, Sol; Dutton, Rachel J.; Boyd, Dana; Beckwith, Jon; Rapoport, Tom A.

    2010-03-19

    Vitamin K epoxide reductase (VKOR) generates vitamin K hydroquinone to sustain {gamma}-carboxylation of many blood coagulation factors. Here, we report the 3.6 {angstrom} crystal structure of a bacterial homologue of VKOR from Synechococcus sp. The structure shows VKOR in complex with its naturally fused redox partner, a thioredoxin-like domain, and corresponds to an arrested state of electron transfer. The catalytic core of VKOR is a four transmembrane helix bundle that surrounds a quinone, connected through an additional transmembrane segment with the periplasmic thioredoxin-like domain. We propose a pathway for how VKOR uses electrons from cysteines of newly synthesized proteins to reduce a quinone, a mechanism confirmed by in vitro reconstitution of vitamin K-dependent disulphide bridge formation. Our results have implications for the mechanism of the mammalian VKOR and explain how mutations can cause resistance to the VKOR inhibitor warfarin, the most commonly used oral anticoagulant.

  11. Divergent evolution of protein conformational dynamics in dihydrofolate reductase

    PubMed Central

    Bhabha, Gira; Ekiert, Damian C.; Jennewein, Madeleine; Zmasek, Christian M.; Tuttle, Lisa M.; Kroon, Gerard; Dyson, H. Jane; Godzik, Adam; Wilson, Ian A.; Wright, Peter E.

    2013-01-01

    Molecular evolution is driven by mutations, which may affect the fitness of an organism and are then subject to natural selection or genetic drift. Analysis of primary protein sequences and tertiary structures has yielded valuable insights into the evolution of protein function, but little is known about evolution of functional mechanisms, protein dynamics and conformational plasticity essential for activity. We characterized the atomic-level motions across divergent members of the dihydrofolate reductase (DHFR) family. Despite structural similarity, E. coli and human DHFRs use different dynamic mechanisms to perform the same function, and human DHFR cannot complement DHFR-deficient E. coli cells. Identification of the primary sequence determinants of flexibility in DHFRs from several species allowed us to propose a likely scenario for the evolution of functionally important DHFR dynamics, following a pattern of divergent evolution that is tuned by the cellular environment. PMID:24077226

  12. Multiple aldehyde reductases of human brain.

    PubMed

    Hoffman, P L; Wermuth, B; von Wartburg, J P

    1980-01-01

    Human brain contains four forms of aldehyde reducing enzymes. One major activity, designated AR3, has properties indicating its identity with the NADPH-dependent aldehyde reductase, EC 1.1.1.2. The other major form of human brain enzyme, AR1, which is also NADPH-dependent, reduces both aldehyde and ketone-containing substrates, including vitamin K3 (menadione) and daunorubicin, a cancer chemotherapeutic agent. This enzyme is very sensitive to inhibition by the flavonoids quercitrin and quercetine, and may be analogous to a daunorubicin reductase previously described in liver of other species. One minor form of human brain aldehyde reductase, AR2, demonstrates substrate specificity and inhibitor sensitivity which suggest its similarity to aldose reductases found in lens and other tissues of many species. This enzyme, which can also use NADH as cofactor to some extent, is the most active in reducing the aldehyde derivatives of the biogenic amines. The fourth human brain enzyme ("SSA reductase") differs from the other forms in its ability to use NADH as well as or better than NADPH as cofactor, and in its molecular weight, which is nearly twice that of the other forms. It is quite specific for succinic semialdehyde (SSA) as substrate, and was found to be significantly inhibited only by quercetine and quercitrin. AR3 can also reduce SSA, and both enzymes may contribute to the production of gamma-hydroxybutyric acid in vivo. These results indicate that the human brain aldehyde reductases can play relatively specific physiologic roles. PMID:7424738

  13. Sequential backbone resonance assignments of the E. coli dihydrofolate reductase Gly67Val mutant: folate complex.

    PubMed

    Puthenpurackal Narayanan, Sunilkumar; Maeno, Akihiro; Wada, Yuji; Tate, Shin-Ichi; Akasaka, Kazuyuki

    2016-04-01

    Occasionally, a mutation in an exposed loop region causes a significant change in protein function and/or stability. A single mutation Gly67Val of E. coli dihydrofolate reductase (DHFR) in the exposed CD loop is such an example. We have carried out the chemical shift assignments for H(N), N(H), C(α) and C(β) atoms of the Gly67Val mutant of E. coli DHFR complexed with folate at pH 7.0, 35 °C, and then evaluated the H(N), N(H), C(α) and C(β) chemical shift changes caused by the mutation. The result indicates that, while the overall secondary structure remains the same, the single mutation Gly67Val causes site-specific conformational changes of the polypeptide backbone restricted around the adenosine-binding subdomain (residues 38-88) and not in the distant catalytic domain. PMID:26482924

  14. Association of MTHFR C677T Genotype With Ischemic Stroke Is Confined to Cerebral Small Vessel Disease Subtype

    PubMed Central

    Traylor, Matthew; Adib-Samii, Poneh; Thijs, Vincent; Sudlow, Cathie; Rothwell, Peter M.; Boncoraglio, Giorgio; Dichgans, Martin; Meschia, James; Maguire, Jane; Levi, Christopher; Rost, Natalia S.; Rosand, Jonathan; Hassan, Ahamad; Bevan, Steve; Markus, Hugh S.

    2016-01-01

    Background and Purpose— Elevated plasma homocysteine levels are associated with stroke. However, this might be a reflection of bias or confounding because trials have failed to demonstrate an effect from homocysteine lowering in stroke patients, although a possible benefit has been suggested in lacunar stroke. Genetic studies could potentially overcome these issues because genetic variants are inherited randomly and are fixed at conception. Therefore, we tested the homocysteine levels–associated genetic variant MTHFR C677T for association with magnetic resonance imaging–confirmed lacunar stroke and compared this with associations with large artery and cardioembolic stroke subtypes. Methods— We included 1359 magnetic resonance imaging–confirmed lacunar stroke cases, 1824 large artery stroke cases, 1970 cardioembolic stroke cases, and 14 448 controls, all of European ancestry. Furthermore, we studied 3670 ischemic stroke patients in whom white matter hyperintensities volume was measured. We tested MTHFR C677T for association with stroke subtypes and white matter hyperintensities volume. Because of the established association of homocysteine with hypertension, we additionally stratified for hypertension status. Results— MTHFR C677T was associated with lacunar stroke (P=0.0003) and white matter hyperintensity volume (P=0.04), but not with the other stroke subtypes. Stratifying the lacunar stroke cases for hypertension status confirmed this association in hypertensive individuals (P=0.0002), but not in normotensive individuals (P=0.30). Conclusions— MTHFR C677T was associated with magnetic resonance imaging–confirmed lacunar stroke, but not large artery or cardioembolic stroke. The association may act through increased susceptibility to, or interaction with, high blood pressure. This heterogeneity of association might explain the lack of effect of lowering homocysteine in secondary prevention trials which included all strokes. PMID:26839351

  15. The KC Channel in the cbb3-Type Respiratory Oxygen Reductase from Rhodobacter capsulatus Is Required for Both Chemical and Pumped Protons

    PubMed Central

    Yıldız, Gülgez Gökçe; Gennis, Robert B.; Daldal, Fevzi

    2014-01-01

    The heme-copper superfamily of proton-pumping respiratory oxygen reductases are classified into three families (A, B, and C families) based on structural and phylogenetic analyses. Most studies have focused on the A family, which includes the eukaryotic mitochondrial cytochrome c oxidase as well as many bacterial homologues. Members of the C family, also called the cbb3-type oxygen reductases, are found only in prokaryotes and are of particular interest because of their presence in a number of human pathogens. All of the heme-copper oxygen reductases require proton-conducting channels to convey chemical protons to the active site for water formation and to convey pumped protons across the membrane. Previous work indicated that there is only one proton-conducting input channel (the KC channel) present in the cbb3-type oxygen reductases, which, if correct, must be utilized by both chemical protons and pumped protons. In this work, the effects of mutations in the KC channel of the cbb3-type oxygen reductase from Rhodobacter capsulatus were investigated by expressing the mutants in a strain lacking other respiratory oxygen reductases. Proton pumping was evaluated by using intact cells, and catalytic oxygen reductase activity was measured in isolated membranes. Two mutations, N346M and Y374F, severely reduced catalytic activity, presumably by blocking the chemical protons required at the active site. One mutation, T272A, resulted in a substantially lower proton-pumping stoichiometry but did not inhibit oxygen reductase activity. These are the first experimental data in support of the postulate that pumped protons are taken up from the bacterial cytoplasm through the KC channel. PMID:24563037

  16. Characterization of thyroidal glutathione reductase

    SciTech Connect

    Raasch, R.J.

    1989-01-01

    Glutathione levels were determined in bovine and rat thyroid tissue by enzymatic conjugation with 1-chloro-2,4-dinitrobenzene using glutathione S-transferase. Bovine thyroid tissue contained 1.31 {+-} 0.04 mM reduced glutathione (GSH) and 0.14 {+-} 0.02 mM oxidized glutathione (GSSG). In the rat, the concentration of GSH was 2.50 {+-} 0.05 mM while GSSG was 0.21 {+-} 0.03 mM. Glutathione reductase (GR) was purified from bovine thyroid to electrophoretic homogeneity by ion exchange, affinity and molecular exclusion chromatography. A molecular weight range of 102-109 kDa and subunit size of 55 kDa were determined for GR. Thyroidal GR was shown to be a favoprotein with one FAD per subunit. The Michaelis constants of bovine thyroidal GR were determined to be 21.8 {mu}M for NADPH and 58.8 {mu}M for GSSG. The effect of thyroid stimulating hormone (TSH) and thyroxine (T{sub 4}) on in vivo levels of GR and glucose 6-phosphate dehydrogenase were determined in rat thyroid homogenates. Both enzymes were stimulated by TSH treatment and markedly reduced following T{sub 4} treatment. Lysosomal hydrolysis of ({sup 125}I)-labeled and unlabeled thyroglobulin was examined using size exclusion HPLC.

  17. Thioredoxin Reductase and its Inhibitors

    PubMed Central

    Saccoccia, Fulvio; Angelucci, Francesco; Boumis, Giovanna; Carotti, Daniela; Desiato, Gianni; Miele, Adriana E; Bellelli, Andrea

    2014-01-01

    Thioredoxin plays a crucial role in a wide number of physiological processes, which span from reduction of nucleotides to deoxyriboucleotides to the detoxification from xenobiotics, oxidants and radicals. The redox function of Thioredoxin is critically dependent on the enzyme Thioredoxin NADPH Reductase (TrxR). In view of its indirect involvement in the above mentioned physio/pathological processes, inhibition of TrxR is an important clinical goal. As a general rule, the affinities and mechanisms of binding of TrxR inhibitors to the target enzyme are known with scarce precision and conflicting results abound in the literature. A relevant analysis of published results as well as the experimental procedures is therefore needed, also in view of the critical interest of TrxR inhibitors. We review the inhibitors of TrxR and related flavoreductases and the classical treatment of reversible, competitive, non competitive and uncompetitive inhibition with respect to TrxR, and in some cases we are able to reconcile contradictory results generated by oversimplified data analysis. PMID:24875642

  18. Functional variants in CYP1B1, KRAS and MTHFR genes are associated with shorter telomere length in postmenopausal women.

    PubMed

    Cerne, Jasmina Z; Pohar-Perme, Maja; Cerkovnik, Petra; Gersak, Ksenija; Novakovic, Srdjan

    2015-07-01

    Estrogens and antioxidants indirectly alleviate telomere attrition. However, available clinical data on the association between hormone exposure and telomere length are inconclusive. In the present study, we examined the effects of exogenous estrogen use and of some genetic factors implicated in estrogen metabolism and oxidative stress response on mean leukocyte telomere length. We studied 259 postmenopausal women. Genotyping was conducted for CYP1B1 (rs1056836), COMT (rs4680), GSTP1 (rs1695), MnSOD (rs4880), KRAS (rs61764370), and MTHFR (rs1801133 and rs1801131) polymorphisms. Mean leukocyte telomere length was measured using a quantitative real-time PCR assay. In multivariate analysis we found no association between oral contraceptives or hormone replacement therapy (HRT) and mean leukocyte telomere length. The presence of variant alleles in CYP1B1, KRAS and MTHFR genes was statistically significantly associated with shorter mean leukocyte telomere length. Further, the data provided evidence for the effect modification of the association between HRT and mean leukocyte telomere length by the CYP1B1, KRAS and MTHFR genotypes. Our findings suggest that functionally relevant genetic variants within estrogen and folate metabolic pathways may influence telomere length. We propose these genetic factors should be taken into consideration when interpreting associations between hormone exposure and telomere length. PMID:25987236

  19. A phase II trial of sequential ribonucleotide reductase inhibition in aggressive myeloproliferative neoplasms

    PubMed Central

    Zeidner, Joshua F.; Karp, Judith E.; Blackford, Amanda L.; Smith, B. Douglas; Gojo, Ivana; Gore, Steven D.; Levis, Mark J.; Carraway, Hetty E.; Greer, Jacqueline M.; Ivy, S. Percy; Pratz, Keith W.; McDevitt, Michael A.

    2014-01-01

    Myeloproliferative neoplasms are a varied group of disorders that can have prolonged chronic phases, but eventually accelerate and can transform into a secondary acute myeloid leukemia that is ultimately fatal. Triapine is a novel inhibitor of the M2 subunit of ribonucleotide reductase. Sequential inhibition of ribonucleotide reductase with triapine and an M1 ribonucleotide reductase inhibitor (fludarabine) was noted to be safe, and led to a 29% complete plus partial response rate in myeloproliferative neoplasms. This article reports the findings of a phase II trial of triapine (105 mg/m2/day) followed by fludarabine (30 mg/m2/day) daily for 5 consecutive days in 37 patients with accelerated myeloproliferative neoplasms and secondary acute myeloid leukemia. The overall response rate was 49% (18/37), with a complete remission rate of 24% (9/37). Overall response rates and complete remissions were seen in all disease subsets, including secondary acute myeloid leukemia, in which the overall response rate and complete remission rate were 48% and 33%, respectively. All patients with known JAK2 V617F mutations (6/6) responded. The median overall survival of the entire cohort was 6.9 months, with a median overall survival of both overall responders and complete responders of 10.6 months. These data further demonstrate the promise of sequential inhibition of ribonucleotide reductase in patients with accelerated myeloproliferative neoplasms and secondary acute myeloid leukemia. This study was registered with clinicaltrials.gov (NCT00381550). PMID:24362550

  20. Characterization and reconstitute of a [Fe4S4] adenosine 5'-phosphosulfate reductase from Acidithiobacillus ferrooxidans.

    PubMed

    Zheng, Chunli; Zhang, Yanfei; Liu, Yuandong; Wu, Anna; Xia, Lexian; Zeng, Jia; Liu, Jianshe; Qiu, Guanzhou

    2009-06-01

    Adenosine 5'-phosphosulfate (APS) reductase is a key enzyme involved in the pathways of sulfate reduction and sulfide oxidation in the biological sulfur cycle. In this study, the gene of APS reductase from Acidithiobacillus ferrooxidans was cloned and expressed in Escherichia coli, the soluble protein was purified by one-step affinity chromatography to apparent homogeneity. The molecular mass of the recombinant APS reductase was determined to be 28 kDa using SDS-PAGE. According to optical and EPR spectra results of the recombinant protein confirmed that the iron-sulfur cluster inserted into the active site of the protein. Site-directed mutation for the enzyme revealed that Cys110, Cys111, Cys193, and Cys196 were in ligation with the iron-sulfur cluster. The [Fe4S4] cluster could be assembled in vitro, and exhibited electron transport and redox catalysis properties. As we know so far, this is the first report of expression in E. coli of APS reductase from A. ferrooxidans. PMID:19225840

  1. Ribonucleotide reductase activity is regulated by proliferating cell nuclear antigen (PCNA)

    PubMed Central

    Salguero, Israel; Guarino, Estrella; Shepherd, Marianne; Deegan, Tom; Havens, Courtney G.; MacNeill, Stuart A.; Walter, Johannes C.; Kearsey, Stephen E.

    2014-01-01

    Summary Synthesis of dNTPs is required for both DNA replication and DNA repair and is catalyzed by ribonucleotide reductases (RNR), which convert ribonucleotides to their deoxy forms [1, 2]. Maintaining the correct levels of dNTPs for DNA synthesis is important for minimising the mutation rate [3-7], and this is achieved by tight regulation of ribonucleotide reductase [2, 8, 9]. In fission yeast, ribonucleotide reductase is regulated in part by a small protein inhibitor, Spd1, which is degraded in S phase and after DNA damage to allow up-regulation of dNTP supply [10-12]. Spd1 degradation is mediated by the activity of the CRL4Cdt2 ubiquitin ligase complex [5, 13, 14]. This has been reported to be dependent on modulation of Cdt2 levels which are cell cycle regulated, peaking in S phase, and which also increase after DNA damage in a checkpoint-dependent manner [7, 13]. We show here that Cdt2 levels fluctuations are not sufficient to regulate Spd1 proteolysis and that the key step in this event is the interaction of Spd1 with the polymerase processivity factor PCNA, complexed onto DNA. This mechanism thus provides a direct link between DNA synthesis and ribonucleotide reductase regulation. PMID:22464192

  2. Structural and mechanistic insights on nitrate reductases.

    PubMed

    Coelho, Catarina; Romão, Maria João

    2015-12-01

    Nitrate reductases (NR) belong to the DMSO reductase family of Mo-containing enzymes and perform key roles in the metabolism of the nitrogen cycle, reducing nitrate to nitrite. Due to variable cell location, structure and function, they have been divided into periplasmic (Nap), cytoplasmic, and membrane-bound (Nar) nitrate reductases. The first crystal structure obtained for a NR was that of the monomeric NapA from Desulfovibrio desulfuricans in 1999. Since then several new crystal structures were solved providing novel insights that led to the revision of the commonly accepted reaction mechanism for periplasmic nitrate reductases. The two crystal structures available for the NarGHI protein are from the same organism (Escherichia coli) and the combination with electrochemical and spectroscopic studies also lead to the proposal of a reaction mechanism for this group of enzymes. Here we present an overview on the current advances in structural and functional aspects of bacterial nitrate reductases, focusing on the mechanistic implications drawn from the crystallographic data. PMID:26362109

  3. Atomic Structure of Salutaridine Reductase from the Opium Poppy (Papaver somniferum)

    SciTech Connect

    Higashi, Yasuhiro; Kutchan, Toni M.; Smith, Thomas J.

    2011-11-18

    The opium poppy (Papaver somniferum L.) is one of the oldest known medicinal plants. In the biosynthetic pathway for morphine and codeine, salutaridine is reduced to salutaridinol by salutaridine reductase (SalR; EC 1.1.1.248) using NADPH as coenzyme. Here, we report the atomic structure of SalR to a resolution of {approx}1.9 {angstrom} in the presence of NADPH. The core structure is highly homologous to other members of the short chain dehydrogenase/reductase family. The major difference is that the nicotinamide moiety and the substrate-binding pocket are covered by a loop (residues 265-279), on top of which lies a large 'flap'-like domain (residues 105-140). This configuration appears to be a combination of the two common structural themes found in other members of the short chain dehydrogenase/reductase family. Previous modeling studies suggested that substrate inhibition is due to mutually exclusive productive and nonproductive modes of substrate binding in the active site. This model was tested via site-directed mutagenesis, and a number of these mutations abrogated substrate inhibition. However, the atomic structure of SalR shows that these mutated residues are instead distributed over a wide area of the enzyme, and many are not in the active site. To explain how residues distal to the active site might affect catalysis, a model is presented whereby SalR may undergo significant conformational changes during catalytic turnover.

  4. Respiratory arsenate reductase as a bidirectional enzyme.

    PubMed

    Richey, Christine; Chovanec, Peter; Hoeft, Shelley E; Oremland, Ronald S; Basu, Partha; Stolz, John F

    2009-05-01

    The haloalkaliphilic bacterium Alkalilimnicola ehrlichii is capable of anaerobic chemolithoautotrophic growth by coupling the oxidation of arsenite (As(III)) to the reduction of nitrate and carbon dioxide. Analysis of its complete genome indicates that it lacks a conventional arsenite oxidase (Aox), but instead possesses two operons that each encode a putative respiratory arsenate reductase (Arr). Here we show that one homolog is expressed under chemolithoautotrophic conditions and exhibits both arsenite oxidase and arsenate reductase activity. We also demonstrate that Arr from two arsenate respiring bacteria, Alkaliphilus oremlandii and Shewanella sp. strain ANA-3, is also biochemically reversible. Thus Arr can function as a reductase or oxidase. Its physiological role in a specific organism, however, may depend on the electron potentials of the molybdenum center and [Fe-S] clusters, additional subunits, or constitution of the electron transfer chain. This versatility further underscores the ubiquity and antiquity of microbial arsenic metabolism. PMID:19285953

  5. Crystal structure of rat liver dihydropteridine reductase.

    PubMed Central

    Varughese, K I; Skinner, M M; Whiteley, J M; Matthews, D A; Xuong, N H

    1992-01-01

    The structure of a binary complex of dihydropteridine reductase [DHPR; NAD(P)H:6,7-dihydropteridine oxidoreductase, EC 1.6.99.7] with its cofactor, NADH, has been solved and refined to a final R factor of 15.4% by using 2.3 A diffraction data. DHPR is an alpha/beta protein with a Rossmann-type dinucleotide fold for NADH binding. Insertion of an extra threonine residue in the human enzyme is associated with severe symptoms of a variant form of phenylketonuria and maps to a tightly linked sequence of secondary-structural elements near the dimer interface. Dimerization is mediated by a four-helix bundle motif (two helices from each protomer) having an unusual right-handed twist. DHPR is structurally and mechanistically distinct from dihydrofolate reductase, appearing to more closely resemble certain nicotinamide dinucleotide-requiring flavin-dependent enzymes, such as glutathione reductase. Images PMID:1631094

  6. Respiratory arsenate reductase as a bidirectional enzyme

    SciTech Connect

    Richey, Christine; Chovanec, Peter; Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282 ; Hoeft, Shelley E.; Oremland, Ronald S.; Basu, Partha; Stolz, John F.

    2009-05-01

    The haloalkaliphilic bacterium Alkalilimnicola ehrlichii is capable of anaerobic chemolithoautotrophic growth by coupling the oxidation of arsenite (As(III)) to the reduction of nitrate and carbon dioxide. Analysis of its complete genome indicates that it lacks a conventional arsenite oxidase (Aox), but instead possesses two operons that each encode a putative respiratory arsenate reductase (Arr). Here we show that one homolog is expressed under chemolithoautotrophic conditions and exhibits both arsenite oxidase and arsenate reductase activity. We also demonstrate that Arr from two arsenate respiring bacteria, Alkaliphilus oremlandii and Shewanella sp. strain ANA-3, is also biochemically reversible. Thus Arr can function as a reductase or oxidase. Its physiological role in a specific organism, however, may depend on the electron potentials of the molybdenum center and [Fe-S] clusters, additional subunits, or constitution of the electron transfer chain. This versatility further underscores the ubiquity and antiquity of microbial arsenic metabolism.

  7. Respiratory arsenate reductase as a bidirectional enzyme

    USGS Publications Warehouse

    Richey, C.; Chovanec, P.; Hoeft, S.E.; Oremland, R.S.; Basu, P.; Stolz, J.F.

    2009-01-01

    The haloalkaliphilic bacterium Alkalilimnicola ehrlichii is capable of anaerobic chemolithoautotrophic growth by coupling the oxidation of arsenite (As(III)) to the reduction of nitrate and carbon dioxide. Analysis of its complete genome indicates that it lacks a conventional arsenite oxidase (Aox), but instead possesses two operons that each encode a putative respiratory arsenate reductase (Arr). Here we show that one homolog is expressed under chemolithoautotrophic conditions and exhibits both arsenite oxidase and arsenate reductase activity. We also demonstrate that Arr from two arsenate respiring bacteria, Alkaliphilus oremlandii and Shewanella sp. strain ANA-3, is also biochemically reversible. Thus Arr can function as a reductase or oxidase. Its physiological role in a specific organism, however, may depend on the electron potentials of the molybdenum center and [Fe–S] clusters, additional subunits, or constitution of the electron transfer chain. This versatility further underscores the ubiquity and antiquity of microbial arsenic metabolism.

  8. Phylogenomics of Mycobacterium Nitrate Reductase Operon.

    PubMed

    Huang, Qinqin; Abdalla, Abualgasim Elgaili; Xie, Jianping

    2015-07-01

    NarGHJI operon encodes a nitrate reductase that can reduce nitrate to nitrite. This process enhances bacterial survival by nitrate respiration under anaerobic conditions. NarGHJI operon exists in many bacteria, especially saprophytic bacteria living in soil which play a key role in the nitrogen cycle. Most actinomycetes, including Mycobacterium tuberculosis, possess NarGHJI operons. M. tuberculosis is a facultative intracellular pathogen that expands in macrophages and has the ability to persist in a non-replicative form in granuloma lifelong. Nitrogen and nitrogen compounds play crucial roles in the struggle between M. tuberculosis and host. M. tuberculosis can use nitrate as a final electron acceptor under anaerobic conditions to enhance its survival. In this article, we reviewed the mechanisms regulating nitrate reductase expression and affecting its activity. Potential genes involved in regulating the nitrate reductase expression in M. tuberculosis were identified. The conserved NarG might be an alternative mycobacterium taxonomic marker. PMID:25980349

  9. Optical observation of correlated motions in dihydrofolate reductase

    NASA Astrophysics Data System (ADS)

    Xu, Mengyang; Niessen, Katherine; Pace, James; Cody, Vivian; Markelz, Andrea

    2015-03-01

    Enzyme function relies on its structural flexibility to make conformational changes for substrate binding and product release. An example of a metabolic enzyme where such structural changes are vital is dihydrofolate reductase (DHFR). DHFR is essential in both prokaryotes and eukaryotes for the nucleotide biosynthesis by catalyzing the reduction of dihydrofolate to tetrahydrofolate. NMR dynamical measurements found large amplitude fast dynamics that could indicate rigid-body, twisting-hinge motion for ecDHFR that may mediate flux. The role of such long-range correlated motions in function was suggested by the observed sharp decrease in enzyme activity for the single point mutation G121V, which is remote from active sites. This decrease in activity may be caused by the mutation interfering with the long-range intramolecular vibrations necessary for rapid access to functional configurations. We use our new technique of crystal anisotropy terahertz microscopy (CATM), to observe correlated motions in ecDHFR crystals with the bonding of NADPH and methotrexate. We compare the measured intramolecular vibrational spectrum with calculations using normal mode analysis.

  10. Functional expression of a Rhodospirillum rubrum gene encoding dinitrogenase reductase ADP-ribosyltransferase in enteric bacteria.

    PubMed

    Fu, H A; Wirt, H J; Burris, R H; Roberts, G P

    1989-12-21

    The function of the cloned draT gene of Rhodospirillum rubrum was studied by placing it under the control of the tac promoter in the vector, pKK223-3. After induction with isopropyl-beta-D-thiogalactopyranoside, dinitrogenase reductase ADP-ribosyltransferase (DRAT) activity was detected in crude extracts of the heterologous hosts Escherichia coli and Klebsiella pneumoniae. In addition, the expression of draT produced a Nif- phenotype in the otherwise wild-type K. pneumoniae strains, the result of the ADP-ribosylation of accumulated dinitrogenase reductase (DR). DR from a nifF- background was also susceptible to ADP-ribosylation, indicating that the oxidized form of DR will serve as a substrate for DRAT in vivo. A mutation that changes the Arg-101 residue of DR, the ADP-ribose attaching site, eliminates the ADP-ribosylation of DR in vivo, confirming the necessity of this residue for modification. PMID:2515993

  11. Evaluation of nitrate reductase activity in Rhizobium japonicum

    SciTech Connect

    Streeter, J.G.; DeVine, P.J.

    1983-08-01

    Nitrate reductase activity was evaluated by four approaches, using four strains of Rhizobium japonicum and 11 chlorate-resistant mutants of the four strains. It was concluded that in vitro assays with bacteria or bacteroids provide the most simple and reliable assessment of the presence or absence of nitrate reductase. Nitrite reductase activity with methyl viologen and dithionite was found, but the enzyme activity does not confound the assay of nitrate reductase. 18 references

  12. 21 CFR 864.7375 - Glutathione reductase assay.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Glutathione reductase assay. 864.7375 Section 864...) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7375 Glutathione reductase assay. (a) Identification. A glutathione reductase assay is a device used to determine...

  13. 21 CFR 864.7375 - Glutathione reductase assay.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Glutathione reductase assay. 864.7375 Section 864...) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7375 Glutathione reductase assay. (a) Identification. A glutathione reductase assay is a device used to determine...

  14. 21 CFR 864.7375 - Glutathione reductase assay.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Glutathione reductase assay. 864.7375 Section 864...) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7375 Glutathione reductase assay. (a) Identification. A glutathione reductase assay is a device used to determine...

  15. 21 CFR 864.7375 - Glutathione reductase assay.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Glutathione reductase assay. 864.7375 Section 864...) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7375 Glutathione reductase assay. (a) Identification. A glutathione reductase assay is a device used to determine...

  16. 21 CFR 864.7375 - Glutathione reductase assay.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Glutathione reductase assay. 864.7375 Section 864...) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7375 Glutathione reductase assay. (a) Identification. A glutathione reductase assay is a device used to determine...

  17. Temperature-sensitive DNA mutant of Chinese hamster ovary cells with a thermolabile ribonucleotide reductase activity.

    PubMed Central

    Wojcik, B E; Dermody, J J; Ozer, H L; Mun, B; Mathews, C K

    1990-01-01

    JB3-B is a Chinese hamster ovary cell mutant previously shown to be temperature sensitive for DNA replication (J. J. Dermody, B. E. Wojcik, H. Du, and H. L. Ozer, Mol. Cell. Biol. 6:4594-4601, 1986). It was chosen for detailed study because of its novel property of inhibiting both polyomavirus and adenovirus DNA synthesis in a temperature-dependent manner. Pulse-labeling studies demonstrated a defect in the rate of adenovirus DNA synthesis. Measurement of deoxyribonucleoside triphosphate (dNTP) pools as a function of time after shift of uninfected cultures from 33 to 39 degrees C revealed that all four dNTP pools declined at similar rates in extracts prepared either from whole cells or from rapidly isolated nuclei. Ribonucleoside triphosphate pools were unaffected by a temperature shift, ruling out the possibility that the mutation affects nucleoside diphosphokinase. However, ribonucleotide reductase activity, as measured in extracts, declined after cell cultures underwent a temperature shift, in parallel with the decline in dNTP pool sizes. Moreover, the activity of cell extracts was thermolabile in vitro, consistent with the model that the JB3-B mutation affects the structural gene for one of the ribonucleotide reductase subunits. The kinetics of dNTP pool size changes after temperature shift are quite distinct from those reported after inhibition of ribonucleotide reductase with hydroxyurea. An indirect effect on ribonucleotide reductase activity in JB3-B has not been excluded since human sequences other than those encoding the enzyme subunits can correct the temperature-sensitive growth defect in the mutant. Images PMID:2233712

  18. Risk of venous thromboembolism associated with single and combined effects of Factor V Leiden, Prothrombin 20210A and Methylenetethraydrofolate reductase C677T: a meta-analysis involving over 11,000 cases and 21,000 controls

    PubMed Central

    Simone, B; De Stefano, V; Leoncini, E; Zacho, J; Martinelli, I; Emmerich, J; Rossi, E; Folsom, AR; Almawi, WY; Scarabin, PY; den Heijer, M; Cushman, M; Penco, S; Vaya, A; Angchaisuksiri, P; Okumus, G; Gemmati, D; Cima, S; Akar, N; Oguzulgen, KI; Ducros, V; Lichy, C; Fernandez-Miranda, C; Szczeklik, A; Nieto, JA; Torres, JD; Le Cam-Duchez, V; Ivanov, P; Cantu, C; Shmeleva, VM; Stegnar, M; Ogunyemi, D; Eid, SS; Nicolotti, N; De Feo, E; Ricciardi, W; Boccia, S

    2014-01-01

    BACKGROUND Genetic and environmental factors interact in determining the risk of venous thromboembolism (VTE). The risk associated with the polymorphic variants G1691A of factor V (Factor V Leiden,FVL), G20210A of prothrombin (PT20210A) and C677T of methylentetrahydrofolate reductase (C677T MTHFR) genes has been investigated in many studies. METHODS We performed a pooled analysis of case-control and cohort studies investigating in adults the association between each variant and VTE, published on Pubmed, Embase or Google through January 2010. Authors of eligible papers, were invited to provide all available individual data for the pooling. The Odds Ratio (OR) for first VTE associated with each variant, individually and combined with the others, were calculated with a random effect model, in heterozygotes and homozygotes (dominant model for FVL and PT20210A; recessive for C677T MTHFR). RESULTS We analysed 31 databases, including 11,239 cases and 21,521 controls. No significant association with VTE was found for homozygous C677T MTHFR (OR: 1.38; 95% confidence intervals [CI]: 0.98–1.93), whereas the risk was increased in carriers of either heterozygous FVL or PT20210 (OR=4.22; 95% CI: 3.35–5.32; and OR=2.79;95% CI: 2.25–3.46, respectively), in double hterozygotes (OR=3.42; 95%CI 1.64-7.13), and in homozygous FVL or PT20210A (OR=11.45; 95%CI: 6.79-19.29; and OR: 2.79; 95%CI: 2.25 – 3.46, respectively). The stratified analyses showed a stronger effect of FVL on individuals ≤45 years (p-value for interaction = 0.036) and of PT20210A in women using oral contraceptives (p-value for interaction = 0.045). CONCLUSIONS In this large pooled analysis, inclusive of large studies like MEGA, no effect was found for C677T MTHFR on VTE; FVL and PT20210A were confirmed to be moderate risk factors. Notably, double carriers of the two genetic variants produced an impact on VTE risk significantly increased but weaker than previously thought. PMID:23900608

  19. Bacteriophage T4 Virion Baseplate Thymidylate Synthetase and Dihydrofolate Reductase

    PubMed Central

    Kozloff, L. M.; Lute, M.; Crosby, L. K.

    1977-01-01

    Additional evidence is presented that both the phage T4D-induced thymidylate synthetase (gp td) and the T4D-induced dihydrofolate reductase (gp frd) are baseplate structural components. With regard to phage td it has been found that: (i) low levels of thymidylate synthetase activity were present in highly purified preparations of T4D ghost particles produced after infection with td+, whereas particles produced after infection with td− had no measurable enzymatic activity; (ii) a mutation of the T4D td gene from tdts to td+ simultaneously produced a heat-stable thymidylate synthetase enzyme and heat-stable phage particles (it should be noted that the phage baseplate structure determines heat lability); (iii) a recombinant of two T4D mutants constructed containing both tdts and frdts genes produced particles whose physical properties indicate that these two molecules physically interact in the baseplate. With regard to phage frd it has been found that two spontaneous revertants each of two different T4D frdts mutants to frd+ not only produced altered dihydrofolate reductases but also formed phage particles with heat sensitivities different from their parents. Properties of T4D particles produced after infection with parental T4D mutants presumed to have a deletion of the td gene and/or the frd gene indicate that these particles still retain some characteristics associated with the presence of both the td and the frd molecules. Furthermore, the particles produced by the deletion mutants have been found to be physically different from the parent particles. PMID:894793

  20. Post-translational Regulation of Nitrate Reductase

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrate reductase (NR) catalyzes the reduction of nitrate to nitrite, which is the first step in the nitrate assimilation pathway, but can also reduce nitrite to nitric oxide (NO), an important signaling molecule that is thought to mediate a wide array of of developmental and physiological processes...

  1. Ferrisiderophore reductase activity in Agrobacterium tumefaciens.

    PubMed Central

    Lodge, J S; Gaines, C G; Arceneaux, J E; Byers, B R

    1982-01-01

    Reduction of the iron in ferriagrobactin by the cytoplasmic fraction of Agrobacterium tumefaciens strictly required NaDH as the reductant. Addition of flavin mononucleotide and anaerobic conditions were necessary for the reaction; when added with flavin mononucleotide, magnesium was stimulatory. This ferrisiderophore reductase activity may be a part of the iron assimilation process in A. tumefaciens. PMID:7056702

  2. The MTHFR 677C-->T polymorphism and behaviors in children with autism: exploratory genotype-phenotype correlations.

    PubMed

    Goin-Kochel, Robin P; Porter, Anne E; Peters, Sarika U; Shinawi, Marwan; Sahoo, Trilochan; Beaudet, Arthur L

    2009-04-01

    New evidence suggests that autism may be associated with (a) varied behavioral responses to folate therapy and (b) metabolic anomalies, including those in folate metabolism, that contribute to hypomethylation of DNA. We hypothesized that children with autism who are homozygous for the MTHFR 677 T allele (TT) and, to a lesser extent those with the CT variant, would exhibit more behavioral problems and/or more severe problematic behaviors than homozygous wild-type (CC) individuals because of difficulties in effectively converting 5,10-MTHF to 5-MTHF. Data from the Autism Genetic Resource Exchange (AGRE) collection were analyzed for all children who met strict criteria for autism per the Autism Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule (ADOS) and who had been genotyped for the 677 C to T MTHFR polymorphism (n=147). Chi-square tests, logistic regression, and one-way ANOVAs were used to determine whether differences existed among MTHFR genotypes for specific behaviors on the ADI-R and indices for level of functioning. Exploratory results indicated four behaviors from the ADI-R that were more common and problematic (95% CI) among those with at least one copy of the T allele as compared to homozygous wild-type individuals: direct gaze, current complex body movements, a history of self-injurious behavior, and current overactivity (ORs=2.72, 2.33, 2.12, 2.47, respectively). No differences existed among genotypes for level of functioning as measured with the Peabody Picture Vocabulary Test-Third Edition, Ravens Colored Progressive Matrices, or the Vineland Adaptive Behavior Scales. Findings call for further investigation of the relationship between folate metabolism and problem behaviors among children with autism. PMID:19455642

  3. Association between the MTHFR C677T polymorphism and risk of cancer: evidence from 446 case-control studies.

    PubMed

    Xie, Shu-Zhe; Liu, Zhi-Zhong; Yu, Jun-hua; Liu, Li; Wang, Wei; Xie, Dao-Lin; Qin, Jiang-Bo

    2015-11-01

    Many molecular epidemiological studies have been performed to explore the association between MTHFR C677T polymorphism and cancer risk in diverse populations. However, the results were inconsistent. Hence, we performed a meta-analysis to investigate the association between cancer risk and MTHFR C677T (150,086 cases and 200,699 controls from 446 studies) polymorphism. Overall, significantly increased cancer risk was found when all eligible studies were pooled into the meta-analysis. In the further stratified and sensitivity analyses, significantly increased breast cancer risk was found in Asians and Indians, significantly decreased colon cancer risk was found, significantly decreased colorectal cancer risk was found in male population, significantly increased gastric cancer risk was found in Caucasians and Asians, significantly increased hepatocellular cancer risk was found in Asians, significantly decreased adult acute lymphoblastic leukemia (AALL) risk was found in Caucasians, significantly decreased childhood acute lymphoblastic leukemia (CALL) risk was found in Asians, and significantly increased multiple myeloma and NHL risk was found in Caucasians. In summary, this meta-analysis suggests that MTHFR C677T polymorphism is associated with increased breast cancer, gastric cancer, and hepatocellular cancer risk in Asians, is associated with increased gastric cancer, multiple myeloma, and NHL risk in Caucasians, is associated with decreased AALL risk in Caucasians, is associated with decreased CALL risk in Asians, is associated with increased breast cancer risk in Asians, is associated with decreased colon cancer risk, and is associated with decreased colorectal cancer risk in male population. Moreover, this meta-analysis also points out the importance of new studies, such as Asians of HNC, Asians of lung cancer, and Indians of breast cancer, because they had high heterogeneity in this meta-analysis (I(2) > 75%). PMID:26081619

  4. Meta-analysis supports association of a functional SNP (rs1801133) in the MTHFR gene with Parkinson's disease.

    PubMed

    Zhu, Zhi-Gang; Ai, Qing-Long; Wang, Wen-Min; Xiao, Zhi-Cheng

    2013-11-15

    The MTHFR is a candidate risk gene for Parkinson's disease (PD), and a functional SNP (rs1801133) in the coding region of this gene has been investigated for the associations with the illness extensively among worldwide populations, but overall the results were inconsistent. Here, to assess the relationship between rs1801133 and risk of PD in general populations, we conducted a systematic meta-analysis by combining all available case-control samples in European and Asian populations, with a total of 1820 PD cases and 7530 healthy controls, and the pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) for rs1801133 and PD were calculated using the Mantel-Haenszel method with a fixed-effect model. Overall, rs1801133 was significantly associated with the risk of PD (allelic model, pooled OR=1.212 for T allele, 95% CI=1.097-1.340, p-value=0.0002). When stratifying for ethnicity, significant association was also observed in European (allelic model, pooled OR=1.187 for T allele, 95% CI=1.058-1.332, p-value=0.004) and Asian samples (allelic model, pooled OR=1.293 for T allele, 95% CI=1.058-1.580, p-value=0.012) respectively. In addition, rs1801133 was also significantly associated with MTHFR mRNA expression in both CEU (European, p-value=0.0149) and CHB (Chinese, p-value=0.0178) HapMap populations. Collectively, our meta-analysis suggests that rs1801133 is significantly associated with susceptibility to PD in European and Asian populations, and MTHFR is likely an authentic risk gene for PD. PMID:23916622

  5. Short Report: Detection of the Dihydrofolate Reductase–164L Mutation in Plasmodium falciparum Infections from Malawi by Heteroduplex Tracking Assay

    PubMed Central

    Juliano, Jonathan J.; Trottman, Paul; Mwapasa, Victor; Meshnick, Steven R.

    2008-01-01

    Standard polymerase chain reaction methods often cannot detect drug-resistance mutations in Plasmodium falciparum infections if the mutation is present in ≤ 20% of the parasites. A heteroduplex tracking assay was developed that can detect dihydrofolate reductase 164-L mutations in variants representing 1% of the parasites in an individual host. Using this assay, we confirmed the presence of the mutation in P. falciparum infections in Malawi. PMID:18541765

  6. Evolution of aldehyde reductase: an immunological approach to the relatedness of aldehyde reductase from different species.

    PubMed

    Davidson, W S; Flynn, T G

    1980-01-01

    Antisera to aldehyde reductase from fruit-fly (Drosophila melanogaster) and chicken were cross-reacted with aldehyde reductase from several species of insects and birds using the technique of microcomplement fixation. Large differences in immunological distances are evident between species of the Class Insecta and of the Class Aves indicating considerable differences in the amino acid sequences of the aldehyde reductase of these species. Immunological distances for aldehyde reductase between pairs of insect species or bird species when plotted against the immunological distances for transferrin, albumin, lysozyme and alpha-glycerophosphate dehydrogenase for the same pairs of species gave a linear relationship in each case. From these relationships the rate of evolution of aldehyde reductase in terms of a unit evolutionary period (UEP) was calculated to be 12 which agreed favorably with the value previously obtained from compositional comparisons. A UEP of 12 is approximately half that of lactate dehydrogenase and shows that aldehyde reductase is evolving at twice the rate of glycolytic enzymes. This may indicate a relatively non-essential metabolism role for the enzyme. PMID:6775512

  7. Control of dihydrofolate reductase messenger ribonucleic acid production.

    PubMed Central

    Leys, E J; Kellems, R E

    1981-01-01

    We used methotrexate-resistant mouse cells in which dihydrofolate reductase levels are approximately 500 times normal to study the effect of growth stimulation on dihydrofolate reductase gene expression. As a result of growth stimulation, the relative rate of dihydrofolate reductase protein synthesis increased threefold, reaching a maximum between 25 and 30 h after stimulation. The relative rate of dihydrofolate reductase messenger ribonucleic acid production (i.e., the appearance of dihydrofolate reductase messenger ribonucleic acid in the cytoplasm) increased threefold after growth stimulation and was accompanied by a corresponding increase in the relative steady-state level of dihydrofolate reductase ribonucleic acid in the nucleus. However, the increase in the nuclear level of dihydrofolate reductase ribonucleic acid was not accompanied by a significant increase in the relative rate of transcription of the dihydrofolate reductase genes. These data indicated that the relative rate of appearance of dihydrofolate reductase messenger ribonucleic acid in the cytoplasm depends on the relative stability of the dihydrofolate reductase ribonucleic acid sequences in the nucleus and is not dependent on the relative rate of transcription of the dihydrofolate reductase genes. PMID:6180296

  8. Methylenetetrahydrofolate reductase deficiency: importance of early diagnosis.

    PubMed

    Fattal-Valevski, A; Bassan, H; Korman, S H; Lerman-Sagie, T; Gutman, A; Harel, S

    2000-08-01

    Methylenetetrahydrofolate reductase deficiency is the most common inborn error of folate metabolism and should be suspected when homocystinuria is combined with hypomethioninemia. The main clinical findings are neurologic signs such as severe developmental delay, marked hypotonia, seizures, microcephaly, apnea, and coma. Most patients present in early life. The infantile form is severe, with rapid deterioration leading to death usually within 1 year. Treatment with betaine has been shown to be efficient in lowering homocysteine concentrations and returning methionine to normal, but the clinical response is variable. We report two brothers with methylenetetrahydrofolate reductase deficiency: the first was undiagnosed and died at 8 months of age from neurologic deterioration and apnea, while his brother, who was treated with betaine from the age of 4 months, is now 3 years old and has developmental delay. PMID:10961793

  9. PAI-1 4G-4G and MTHFR 677TT in non-hepatitis C virus/hepatitis B virus-related liver cirrhosis

    PubMed Central

    Pasta, Linda; Pasta, Francesca

    2015-01-01

    AIM: To evaluate the different roles of thrombophilia in patients with and without viral etiology. The thrombophilic genetic factors (THRGFs), PAI-1 4G-4G, MTHFR 677TT, V Leiden 506Q and prothrombin 20210A, were studied as risk factors in 1079 patients with liver cirrhosis (LC), enrolled from January 2000 to January 2014. METHODS: All Caucasian LC patients consecutively observed in a fourteen-year period were included; the presence of portal vein thrombosis (PVT) and Budd Chiari syndrome (BCS) was registered. The differences between the proportions of each THRGF with regard to the presence or absence of viral etiology and the frequencies of the THRGF genotypes with those predicted in a population by the Hardy-Weinberg equilibrium were registered. RESULTS: Four hundred and seventeen/one thousand and seventy-six patients (38.6%) showed thrombophilia: 217 PAI-1 4G-4G, 176 MTHFR C677TT, 71 V Leiden factor and 41 prothrombin G20210 A, 84 with more than 1 THRGF; 350 presented with no viral liver cirrhosis (NVLC) and 729 with, called viral liver cirrhosis (VLC), of whom 56 patients were hepatitis C virus + hepatitis B virus. PAI-1 4G-4G, MTHFR C677TT, the presence of at least one TRHGF and the presence of > 1 THRGF, were statistically more frequent in patients with NVLC vs patients with VLC: All χ2 > 3.85 and P < 0.05. Patients with PVT and/or BCS with at least one TRHGF were 189/352 (53.7%). The Hardy-Weinberg of PAI-1 and MTHFR 677 genotypes deviated from that expected from a population in equilibrium in patients with NVLC (respectively χ2 = 39.3; P < 0.000 and χ2 = 27.94; P < 0.05), whereas the equilibrium was respected in VLC. CONCLUSION: MTHFR 677TT was nearly twofold and PAI-1 4G-4G more than threefold more frequently found in NVLC vs patients with VLC; the Hardy-Weinberg equilibrium of these two polymorphisms confirms this data in NVLC. We suggest that PAI-1 4G-4G and MTHFR 677TT could be considered as factors of fibrosis and thrombosis mechanisms, increasing the inflammation response, and causing the hepatic fibrosis and augmented intrahepatic vascular resistance typical of LC. PAI-1 4G-4G and MTHFR 677TT screening of LC patients could be useful, mainly in those with NVLC, to identify patients in which new drug therapies based on the attenuation of the hepatic stellate cells activation or other mechanisms could be more easily evaluated. PMID:26689658

  10. Predicting Resistance Mutations Using Protein Design Algorithms

    SciTech Connect

    Frey, K.; Georgiev, I; Donald, B; Anderson, A

    2010-01-01

    Drug resistance resulting from mutations to the target is an unfortunate common phenomenon that limits the lifetime of many of the most successful drugs. In contrast to the investigation of mutations after clinical exposure, it would be powerful to be able to incorporate strategies early in the development process to predict and overcome the effects of possible resistance mutations. Here we present a unique prospective application of an ensemble-based protein design algorithm, K*, to predict potential resistance mutations in dihydrofolate reductase from Staphylococcus aureus using positive design to maintain catalytic function and negative design to interfere with binding of a lead inhibitor. Enzyme inhibition assays show that three of the four highly-ranked predicted mutants are active yet display lower affinity (18-, 9-, and 13-fold) for the inhibitor. A crystal structure of the top-ranked mutant enzyme validates the predicted conformations of the mutated residues and the structural basis of the loss of potency. The use of protein design algorithms to predict resistance mutations could be incorporated in a lead design strategy against any target that is susceptible to mutational resistance.

  11. Competition between Escherichia coli strains expressing either a periplasmic or a membrane-bound nitrate reductase: does Nap confer a selective advantage during nitrate-limited growth?

    PubMed

    Potter, L C; Millington, P; Griffiths, L; Thomas, G H; Cole, J A

    1999-11-15

    The physiological role of the periplasmic nitrate reductase, Nap, one of the three nitrate reductases synthesized by Escherichia coli K-12, has been investigated. A series of double mutants that express only one nitrate reductase were grown anaerobically in batch cultures with glycerol as the non-fermentable carbon source and nitrate as the terminal electron acceptor. Only the strain expressing nitrate reductase A grew rapidly under these conditions. Introduction of a narL mutation severely decreased the growth rate of the nitrate reductase A strain, but enhanced the growth of the Nap(+) strain. The ability to use nitrate as a terminal electron acceptor for anaerobic growth is therefore regulated primarily by the NarL protein at the level of transcription. Furthermore, the strain expressing nitrate reductase A had a substantial selective advantage in competition with the strain expressing only Nap during nitrate-sufficient continuous culture. However, the strain expressing Nap was preferentially selected during nitrate-limited continuous growth. The saturation constants for nitrate for the two strains (which numerically are equal to the nitrate concentrations at half of the maximum specific growth rate and therefore reflect the relative affinities for nitrate) were estimated using the integrated Monod equation to be 15 and 50 microM for Nap and nitrate reductase A respectively. This difference is sufficient to explain the selective advantage of the Nap(+) strain during nitrate-limited growth. It is concluded that one physiological role of the periplasmic nitrate reductase of enteric bacteria is to enable bacteria to scavenge nitrate in nitrate-limited environments. PMID:10548536

  12. A Ferredoxin Disulfide Reductase Delivers Electrons to the Methanosarcina barkeri Class III Ribonucleotide Reductase.

    PubMed

    Wei, Yifeng; Li, Bin; Prakash, Divya; Ferry, James G; Elliott, Sean J; Stubbe, JoAnne

    2015-12-01

    Two subtypes of class III anaerobic ribonucleotide reductases (RNRs) studied so far couple the reduction of ribonucleotides to the oxidation of formate, or the oxidation of NADPH via thioredoxin and thioredoxin reductase. Certain methanogenic archaea contain a phylogenetically distinct third subtype of class III RNR, with distinct active-site residues. Here we report the cloning and recombinant expression of the Methanosarcina barkeri class III RNR and show that the electrons required for ribonucleotide reduction can be delivered by a [4Fe-4S] protein ferredoxin disulfide reductase, and a conserved thioredoxin-like protein NrdH present in the RNR operon. The diversity of class III RNRs reflects the diversity of electron carriers used in anaerobic metabolism. PMID:26536144

  13. Inefficient Translation Renders the Enterococcus faecalis fabK Enoyl-Acyl Carrier Protein Reductase Phenotypically Cryptic

    PubMed Central

    Bi, Hongkai; Zhu, Lei

    2014-01-01

    Enoyl-acyl carrier protein (ACP) reductase catalyzes the last step of the bacterial fatty acid elongation cycle. Enterococcus faecalis is unusual in that it encodes two unrelated enoyl-ACP reductases, FabI and FabK. We recently reported that deletion of the gene encoding FabI results in an unsaturated fatty acid (UFA) auxotroph despite the presence of fabK, a gene encoding a second fully functional enoyl-ACP reductase. By process of elimination, our prior report argued that poor expression was the reason that fabK failed to functionally replace FabI. We now report that FabK is indeed poorly expressed and that the expression defect is at the level of translation rather than transcription. We isolated four spontaneous mutants that allowed growth of the E. faecalis ΔfabI strain on fatty acid-free medium. Each mutational lesion (single base substitution or deletion) extended the fabK ribosome binding site. Inactivation of fabK blocked growth, indicating that the mutations acted only on fabK rather than a downstream gene. The mutations activated fabK translation to levels that supported fatty acid synthesis and hence cell growth. Furthermore, site-directed and random mutagenesis experiments showed that point mutations that resulted in increased complementarity to the 3′ end of the 16S rRNA increased FabK translation to levels sufficient to support growth, whereas mutations that decreased complementarity blocked fabK translation. PMID:24163335

  14. S-nitrosoglutathione reductase in human lung cancer.

    PubMed

    Marozkina, Nadzeya V; Wei, Christina; Yemen, Sean; Wallrabe, Horst; Nagji, Alykhan S; Liu, Lei; Morozkina, Tatiana; Jones, David R; Gaston, Benjamin

    2012-01-01

    S-Nitrosoglutathione (GSNO) reductase regulates cell signaling pathways relevant to asthma and protects cells from nitrosative stress. Recent evidence suggests that this enzyme may prevent human hepatocellular carcinoma arising in the setting of chronic hepatitis. We hypothesized that GSNO reductase may also protect the lung against potentially carcinogenic reactions associated with nitrosative stress. We report that wild-type Ras is S-nitrosylated and activated by nitrosative stress and that it is denitrosylated by GSNO reductase. In human lung cancer, the activity and expression of GSNO reductase are decreased. Further, the distribution of the enzyme (including its colocalization with wild-type Ras) is abnormal. We conclude that decreased activity of GSNO reductase could leave the human lung vulnerable to the oncogenic effects of nitrosative stress, as is the case in the liver. This potential should be considered when developing therapies that inhibit pulmonary GSNO reductase to treat asthma and other conditions. PMID:21816964

  15. Characterization of Nitrate Reductase Deficient Mutants of Chlorella sorokiniana

    PubMed Central

    Knobloch, Otto; Tischner, Rudolf

    1989-01-01

    After x-ray irradiation, 13 mutants of Chlorella sorokiniana incapable of using NO3− as N source were isolated using a pinpoint method. Using immunoprecipitation and Western blot assays, no nitrate reductase was found in five strains while in eight mutants the enzyme was detected. The latter strains contained different patterns of nitrate reductase partial reactions. All isolates were of the nia-type as indicated by the inducibility of purine hydroxylase I and by complementation of nitrate reductase activity in the Neurospora crassa mutant Nit-1. A restoration of NADP-nitrate reductase in Nit-1 was also obtained with NH4+-grown cells indicating that Mo-cofactor is constitutive in Chlorella. Complementation experiments among the Chlorella mutants resulted in restoration of NADH-nitrate reductase activity. The characteristics of some of the Chlorella mutants are discussed in view of an improper orientation of Mo-cofactor in the residual nitrate reductase protein. Images Figure 3 PMID:16666622

  16. Evidence for a Ustilago maydis steroid 5alpha-reductase by functional expression in Arabidopsis det2-1 mutants.

    PubMed

    Basse, Christoph W; Kerschbamer, Christine; Brustmann, Markus; Altmann, Thomas; Kahmann, Regine

    2002-06-01

    We have identified a gene (udh1) in the basidiomycete Ustilago maydis that is induced during the parasitic interaction with its host plant maize (Zea mays). udh1 encodes a protein with high similarity to mammalian and plant 5alpha-steroid reductases. Udh1 differs from those of known 5alpha-steroid reductases by six additional domains, partially predicted to be membrane-spanning. A fusion protein of Udh1 and the green fluorescent protein provided evidence for endoplasmic reticulum localization in U. maydis. The function of the Udh1 protein was demonstrated by complementing Arabidopsis det2-1 mutants, which display a dwarf phenotype due to a mutation in the 5alpha-steroid reductase encoding DET2 gene. det2-1 mutant plants expressing either the udh1 or the DET2 gene controlled by the cauliflower mosaic virus 35S promoter differed from wild-type Columbia plants by accelerated stem growth, flower and seed development and a reduction in size and number of rosette leaves. The accelerated growth phenotype of udh1 transgenic plants was stably inherited and was favored under reduced light conditions. Truncation of the N-terminal 70 amino acids of the Udh1 protein abolished the ability to restore growth in det2-1 plants. Our results demonstrate the existence of a 5alpha-steroid reductase encoding gene in fungi and suggest a common ancestor between fungal, plant, and mammalian proteins. PMID:12068114

  17. Construction of a dihydrofolate reductase-deficient mutant of Escherichia coli by gene replacement.

    PubMed

    Howell, E E; Foster, P G; Foster, L M

    1988-07-01

    The dihydrofolate reductase (fol) gene in Escherichia coli has been deleted and replaced by a selectable marker. Verification of the delta fol::kan strain has been accomplished using genetic and biochemical criteria, including Southern analysis of the chromosomal DNA. The delta fol::kan mutation is stable in E. coli K549 [thyA polA12 (Ts)] and can be successfully transduced to other E. coli strains providing they have mutations in their thymidylate synthetase (thyA) genes. A preliminary investigation of the relationship between fol and thyA gene expression suggests that a Fol- cell (i.e., a dihydrofolate reductase deficiency phenotype) is not viable unless thymidylate synthetase activity is concurrently eliminated. This observation indicates that either the nonproductive accumulation of dihydrofolate or the depletion of tetrahydrofolate cofactor pools is lethal in a Fol- ThyA+ strain. Strains containing the thyA delta fol::kan lesions require the presence of Fol end products for growth, and these lesions typically increase the doubling time of the strain by a factor of 2.5 in rich medium. PMID:2838456

  18. Asynchronous Bilateral Renal Infarction and Thrombophilia With Associated Gene Mutations in a 43-Year-Old Man: A Case Report.

    PubMed

    Zhou, Xu-Jie; Liu, Li-Jun; Chen, Min; Zhou, Fu-De

    2016-04-01

    Renal infarction (RI) is frequently misdiagnosed or diagnosed late because of its rarity and nonspecific clinical presentation, which may result in irreversible damage to the renal parenchyma or increase the risk of other embolic events affecting additional organs. Multiple causal mechanisms and cases of idiopathic RI have been reported, but the causal factors are not clear in most cases.Here, we report the case of a patient with heterochronic bilateral RI caused by thrombophilia. Although he had several risk factors for hypercoagulation disorders, two gene mutations-MTHFR 677 C>T and PLG 1858G>A-were identified by genome sequencing of the entire exome. The findings suggest the possibility of a synergistic relationship between the two gene mutations.Thus, screening for gene mutations may provide additional clues for clarifying the cause of RI and thrombophilia. PMID:27057875

  19. Structure and function of NADPH-cytochrome P450 reductase and nitric oxide synthase reductase domain

    SciTech Connect

    Iyanagi, Takashi . E-mail: iyanagi@spring8.or.jp

    2005-12-09

    NADPH-cytochrome P450 reductase (CPR) and the nitric oxide synthase (NOS) reductase domains are members of the FAD-FMN family of proteins. The FAD accepts two reducing equivalents from NADPH (dehydrogenase flavin) and FMN acts as a one-electron carrier (flavodoxin-type flavin) for the transfer from NADPH to the heme protein, in which the FMNH {sup {center_dot}}/FMNH{sub 2} couple donates electrons to cytochrome P450 at constant oxidation-reduction potential. Although the interflavin electron transfer between FAD and FMN is not strictly regulated in CPR, electron transfer is activated in neuronal NOS reductase domain upon binding calmodulin (CaM), in which the CaM-bound activated form can function by a similar mechanism to that of CPR. The oxygenated form and spin state of substrate-bound cytochrome P450 in perfused rat liver are also discussed in terms of stepwise one-electron transfer from CPR. This review provides a historical perspective of the microsomal mixed-function oxidases including CPR and P450. In addition, a new model for the redox-linked conformational changes during the catalytic cycle for both CPR and NOS reductase domain is also discussed.

  20. A Peroxisomal Disorder of Severe Intellectual Disability, Epilepsy, and Cataracts Due to Fatty Acyl-CoA Reductase 1 Deficiency

    PubMed Central

    Buchert, Rebecca; Tawamie, Hasan; Smith, Christopher; Uebe, Steffen; Innes, A. Micheil; Al Hallak, Bassam; Ekici, Arif B.; Sticht, Heinrich; Schwarze, Bernd; Lamont, Ryan E.; Parboosingh, Jillian S.; Bernier, Francois P.; Abou Jamra, Rami

    2014-01-01

    Rhizomelic chondrodysplasia punctata (RCDP) is a group of disorders with overlapping clinical features including rhizomelia, chondrodysplasia punctata, coronal clefts, cervical dysplasia, congenital cataracts, profound postnatal growth retardation, severe intellectual disability, and seizures. Mutations in PEX7, GNPAT, and AGPS, all involved in the plasmalogen-biosynthesis pathway, have been described in individuals with RCDP. Here, we report the identification of mutations in another gene in plasmalogen biosynthesis, fatty acyl-CoA reductase 1 (FAR1), in two families affected by severe intellectual disability, early-onset epilepsy, microcephaly, congenital cataracts, growth retardation, and spasticity. Exome analyses revealed a homozygous in-frame indel mutation (c.495_507delinsT [p.Glu165_Pro169delinsAsp]) in two siblings from a consanguineous family and compound-heterozygous mutations (c.[787C>T];[1094A>G], p.[Arg263∗];[Asp365Gly]) in a third unrelated individual. FAR1 reduces fatty acids to their respective fatty alcohols for the plasmalogen-biosynthesis pathway. To assess the pathogenicity of the identified mutations, we transfected human embryonic kidney 293 cells with plasmids encoding FAR1 with either wild-type or mutated constructs and extracted the lipids from the cells. We screened the lipids with gas chromatography and mass spectrometry and found that all three mutations abolished the reductase activity of FAR1, given that no fatty alcohols could be detected. We also observed reduced plasmalogens in red blood cells in one individual to a range similar to that seen in individuals with RCDP, further supporting abolished FAR1 activity. We thus expand the spectrum of clinical features associated with defects in plasmalogen biosynthesis to include FAR1 deficiency as a cause of syndromic severe intellectual disability with cataracts, epilepsy, and growth retardation but without rhizomelia. PMID:25439727

  1. A peroxisomal disorder of severe intellectual disability, epilepsy, and cataracts due to fatty acyl-CoA reductase 1 deficiency.

    PubMed

    Buchert, Rebecca; Tawamie, Hasan; Smith, Christopher; Uebe, Steffen; Innes, A Micheil; Al Hallak, Bassam; Ekici, Arif B; Sticht, Heinrich; Schwarze, Bernd; Lamont, Ryan E; Parboosingh, Jillian S; Bernier, Francois P; Abou Jamra, Rami

    2014-11-01

    Rhizomelic chondrodysplasia punctata (RCDP) is a group of disorders with overlapping clinical features including rhizomelia, chondrodysplasia punctata, coronal clefts, cervical dysplasia, congenital cataracts, profound postnatal growth retardation, severe intellectual disability, and seizures. Mutations in PEX7, GNPAT, and AGPS, all involved in the plasmalogen-biosynthesis pathway, have been described in individuals with RCDP. Here, we report the identification of mutations in another gene in plasmalogen biosynthesis, fatty acyl-CoA reductase 1 (FAR1), in two families affected by severe intellectual disability, early-onset epilepsy, microcephaly, congenital cataracts, growth retardation, and spasticity. Exome analyses revealed a homozygous in-frame indel mutation (c.495_507delinsT [p.Glu165_Pro169delinsAsp]) in two siblings from a consanguineous family and compound-heterozygous mutations (c.[787C>T];[1094A>G], p.[Arg263(∗)];[Asp365Gly]) in a third unrelated individual. FAR1 reduces fatty acids to their respective fatty alcohols for the plasmalogen-biosynthesis pathway. To assess the pathogenicity of the identified mutations, we transfected human embryonic kidney 293 cells with plasmids encoding FAR1 with either wild-type or mutated constructs and extracted the lipids from the cells. We screened the lipids with gas chromatography and mass spectrometry and found that all three mutations abolished the reductase activity of FAR1, given that no fatty alcohols could be detected. We also observed reduced plasmalogens in red blood cells in one individual to a range similar to that seen in individuals with RCDP, further supporting abolished FAR1 activity. We thus expand the spectrum of clinical features associated with defects in plasmalogen biosynthesis to include FAR1 deficiency as a cause of syndromic severe intellectual disability with cataracts, epilepsy, and growth retardation but without rhizomelia. PMID:25439727

  2. Reduction of tetrathionate by mammalian thioredoxin reductase

    PubMed Central

    Narayan, Vivek; Kudva, Avinash K.; Prabhu, K. Sandeep

    2016-01-01

    Tetrathionate, a polythionate oxidation product of microbial hydrogen sulfide and reactive oxygen species from immune cells in the gut, serves as a terminal electron acceptor to confer growth advantage for Salmonella and other enterobacteria. Here we show that the rat liver selenoen-zyme thioredoxin reductase (Txnrd1; TR1) efficiently reduces tetrathionate in vitro. Furthermore, lysates of selenium-supplemented murine macrophages also displayed activity towards tetrathionate, while cells lacking TR1 were unable to reduce tetrathionate. These studies suggest that upregulation of TR1 expression, via selenium supplementation, may modulate the gut microbiome, particularly during inflammation, by regulating the levels of tetrathionate. PMID:26252619

  3. Kinetics of befunolol reductase from rabbit liver.

    PubMed

    Nozaki, Y; Imamura, Y; Otagiri, M

    1990-01-01

    The kinetic mechanism for the reduction of befunolol catalyzed by befunolol reductase from rabbit liver was investigated. From the initial velocity analysis, product inhibition and coenzyme binding studies, the reduction of befunolol was found to proceed through an ordered Bi Bi mechanism, in which beta-nicotinamide adenine dinucleotide phosphate, reduced form (NADPH) binds to the enzyme firstly and NADP+ leaves lastly. NADPH bound to the free enzyme at a molar ratio of 1:1. Furthermore, the result of dead-end inhibition by Cibacron blue F3GA, a nucleotide analogue which binds to many enzymes, was consistent with the ordered Bi Bi mechanism for the enzyme. PMID:2186874

  4. One carbon metabolism disturbances and the C677T MTHFR gene polymorphism in children with autism spectrum disorders.

    PubMed

    Paşca, Sergiu P; Dronca, Eleonora; Kaucsár, Tamás; Craciun, Elena C; Endreffy, Emõke; Ferencz, Beatrix K; Iftene, Felicia; Benga, Ileana; Cornean, Rodica; Banerjee, Ruma; Dronca, Maria

    2009-10-01

    Autism spectrum disorders (ASDs), which include the prototypic autistic disorder (AD), Asperger's syndrome (AS) and pervasive developmental disorders not otherwise specified (PDD-NOS), are complex neurodevelopmental conditions of unknown aetiology. The current study investigated the metabolites in the methionine cycle, the transsulphuration pathway, folate, vitamin B(12) and the C677T polymorphism of the MTHFR gene in three groups of children diagnosed with AD (n= 15), AS (n= 5) and PDD-NOS (n= 19) and their age- and sex-matched controls (n= 25). No metabolic disturbances were seen in the AS patients, while in the AD and PDD-NOS groups, lower plasma levels of methionine (P= 0.01 and P= 0.03, respectively) and alpha-aminobutyrate were observed (P= 0.01 and P= 0.001, respectively). Only in the AD group, plasma cysteine (P= 0.02) and total blood glutathione (P= 0.02) were found to be reduced. Although there was a trend towards lower levels of serine, glycine, N, N-dimethylglycine in AD patients, the plasma levels of these metabolites as well as the levels of homocysteine and cystathionine were not statistically different in any of the ASDs groups. The serum levels of vitamin B(12) and folate were in the normal range. The results of the MTHFR gene analysis showed a normal distribution of the C677T polymorphism in children with ASDs, but the frequency of the 677T allele was slightly more prevalent in AD patients. Our study indicates a possible role for the alterations in one carbon metabolism in the pathophysiology of ASDs and provides, for the first time, preliminary evidence for metabolic and genetic differences between clinical subtypes of ASDs. PMID:19267885

  5. Pharmacogenetic variants in the DPYD, TYMS, CDA and MTHFR genes are clinically significant predictors of fluoropyrimidine toxicity

    PubMed Central

    Loganayagam, A; Arenas Hernandez, M; Corrigan, A; Fairbanks, L; Lewis, C M; Harper, P; Maisey, N; Ross, P; Sanderson, J D; Marinaki, A M

    2013-01-01

    Background: Fluoropyrimidine drugs are extensively used for the treatment of solid cancers. However, adverse drug reactions are a major clinical problem, often necessitating treatment discontinuation. The aim of this study was to identify pharmacogenetic markers predicting fluoropyrimidine toxicity. Methods: Toxicity in the first four cycles of 5-fluorouracil or capecitabine-based chemotherapy were recorded for a series of 430 patients. The association between demographic variables, DPYD, DPYS, TYMS, MTHFR, CDA genotypes, and toxicity were analysed using logistic regression models. Results: Four DPYD sequence variants (c.1905+1G>A, c.2846A>T, c.1601G>A and c.1679T>G) were found in 6% of the cohort and were significantly associated with grade 3–4 toxicity (P<0.0001). The TYMS 3′-untranslated region del/del genotype substantially increased the risk of severe toxicity (P=0.0123, odds ratio (OR)=3.08, 95% confidence interval (CI): 1.38–6.87). For patients treated with capecitabine, a MTHFR c.1298CC homozygous variant genotype predicted hand–foot syndrome (P=4.1 × 10−6, OR=9.99, 95% CI: 3.84–27.8). The linked CDA c.−92A>G and CDA c.−451C>T variants predicted grade 2–4 diarrhoea (P=0.0055, OR=2.3, 95% CI: 1.3–4.2 and P=0.0082, OR=2.3, 95% CI: 1.3–4.2, respectively). Conclusion: We have identified a panel of clinically useful pharmacogenetic markers predicting toxicity to fluoropyrimidine therapy. Dose reduction should be considered in patients carrying these sequence variants. PMID:23736036

  6. S-nitrosoglutathione reductase deficiency increases mutagenesis from alkylation in mouse liver.

    PubMed

    Leung, James; Wei, Wei; Liu, Limin

    2013-05-01

    In human hepatocellular carcinoma (HCC) and many other cancers, somatic point mutations are highly prevalent, yet the mechanisms critical in their generation remain poorly understood. S-nitrosoglutathione reductase (GSNOR), a key regulator of protein S-nitrosylation, is frequently deficient in human HCC. Targeted deletion of the GSNOR gene in mice can reduce the activity of the DNA repair protein O (6)-alkylguanine-DNA alkyltransferase (AGT) and promote both carcinogen-induced and spontaneous HCC. In this study, we report that following exposure to the environmental carcinogen diethylnitrosamine, the mutation frequency of a transgenic reporter in the liver of GSNOR-deficient mice (GSNOR(-/-)) is significantly higher than that in wild-type control. In wild-type mice, diethylnitrosamine treatment does not significantly increase the frequency of the transition from G:C to A:T, a mutation deriving from diethylnitrosamine-induced O (6)-ethylguanines that are normally repaired by AGT. In contrast, the frequency of this transition from diethylnitrosamine is increased ~20 times in GSNOR(-/-) mice. GSNOR deficiency also significantly increases the frequency of the transversion from A:T to T:A, a mutation not affected by AGT. GSNOR deficiency in our experiments does not significantly affect either the frequencies of the other diethylnitrosamine-induced point mutations or hepatocyte proliferation. Thus, GSNOR deficiency, through both AGT-dependent and AGT-independent pathways, significantly raises the rates of specific types of DNA mutations. Our results demonstrate a critical role for GSNOR in maintaining genomic integrity in mice and support the hypothesis that GSNOR deficiency is an important cause of the widespread mutations in human HCC. PMID:23354311

  7. Molecular study of the 5 {alpha}-reductase type 2 gene in three European families with 5 {alpha}-reductase deficiency

    SciTech Connect

    Boudon, C.; Lumbroso, S.; Lobaccaro, J.M.

    1995-07-01

    The molecular basis of 5{alpha}-reductase (5{alpha}R) deficiency was investigated in four patients from three European families. In the French family, the first patient was raised as a female, and gonadectomy was performed before puberty. The second sibling, also raised as female, differed in that gonadal removal was performed after the onset of pubertal masculinization. The other two patients, both from Polish families, developed masculinization of external genitalia during puberty. All patients developed a female sexual identity. In all cases, no known consanguinity or family history of 5{alpha}R deficiency was reported. The genomic DNAs of the patients were sequenced after polymerase chain reaction amplification of the five exons of the 5{alpha}R type 2 gene. We found two homozygous mutations responsible for gutamine to arginine and histidine to arginine substitution in families 1 and 3, respectively. In family 2, we found a heterozygous mutation responsible for an asparagine to serine substitution at position 193. The glutamine/arginine 126 mutation in the French family was previously reported in a Creole ethnic group, and the Polish histidine/arginine 231 mutation was previously reported in a patient from Chicago, Moreover, all of the mutations created new restriction sites, which were used to determine the kindred carrier status in the three families. Because 5{alpha}R deficiency is known to be heterogenous disease in terms of clinical and biochemical expression, our data suggest that molecular biology analysis of the type 2 gene could be an essential step in diagnosing 5{alpha}R deficiency. 22 refs., 3 figs., 1 tab.

  8. Biliverdin reductase: a target for cancer therapy?

    PubMed Central

    Gibbs, Peter E. M.; Miralem, Tihomir; Maines, Mahin D.

    2015-01-01

    Biliverdin reductase (BVR) is a multifunctional protein that is the primary source of the potent antioxidant, bilirubin. BVR regulates activities/functions in the insulin/IGF-1/IRK/PI3K/MAPK pathways. Activation of certain kinases in these pathways is/are hallmark(s) of cancerous cells. The protein is a scaffold/bridge and intracellular transporter of kinases that regulate growth and proliferation of cells, including PKCs, ERK and Akt, and their targets including NF-κB, Elk1, HO-1, and iNOS. The scaffold and transport functions enable activated BVR to relocate from the cytosol to the nucleus or to the plasma membrane, depending on the activating stimulus. This enables the reductase to function in diverse signaling pathways. And, its expression at the transcript and protein levels are increased in human tumors and the infiltrating T-cells, monocytes and circulating lymphocytes, as well as the circulating and infiltrating macrophages. These functions suggest that the cytoprotective role of BVR may be permissive for cancer/tumor growth. In this review, we summarize the recent developments that define the pro-growth activities of BVR, particularly with respect to its input into the MAPK signaling pathway and present evidence that BVR-based peptides inhibit activation of protein kinases, including MEK, PKCδ, and ERK as well as downstream targets including Elk1 and iNOS, and thus offers a credible novel approach to reduce cancer cell proliferation. PMID:26089799

  9. 3-Methyleneoxindole Reductase of Peas 1

    PubMed Central

    Moyed, H. S.; Williamson, Valerie

    1967-01-01

    A 100-fold purification of a reduced triphosphopyridine nucleotide/3-methyleneoxindole reductase of peas has been achieved using conventional protein fractionation procedures. Reduced diphosphopyridine nucleotide is 25-fold less effective than reduced triphosphopyridine nucleotide as the reductant. The preparation is free of other reductase activities including those linking the oxidation of reduced pyridine nucleotide coenzymes to the reduction of cytochrome c; vitamins K1, K2, and K3; O2; nitrate; oxidized glutathione; and thiazolyl blue tetrazolium. The affinity of the enzyme for 3-methyleneoxindole (Ks = 0.5 mm 3-methyleneoxindole) is relatively high. It is, therefore, reasonable to assume that 3-methyleneoxindole is the normal substrate. The enzyme is inhibited by indole-3-acetic acid, indole-3-aldehyde, and by l-naph-thaleneacetic acid. While these are not especially powerful inhibitors (K1 = 1.9-4.0 mm) the competitive relationship with 3-methyleneoxindole indicates that significant inhibition might occur at low intracellular concentrations of the substrate. PMID:6042360

  10. Reduced Impact of Pyrimethamine Drug Pressure on Plasmodium malariae Dihydrofolate Reductase Gene

    PubMed Central

    Khim, Nimol; Kim, Saorin; Bouchier, Christiane; Tichit, Magali; Ariey, Frédéric; Fandeur, Thierry; Chim, Pheaktra; Ke, Sopheakvatey; Sum, Sarorn; Man, Somnang; Ratsimbasoa, Arsène; Durand, Rémy

    2012-01-01

    Molecular investigations performed following the emergence of sulfadoxine-pyrimethamine (SP) resistance in Plasmodium falciparum have allowed the identification of the dihydrofolate reductase (DHFR) enzyme as the target of pyrimethamine. Although clinical cases of Plasmodium malariae are not usually treated with antifolate therapy, incorrect diagnosis and the high frequency of undetected mixed infections has probably exposed non-P. falciparum parasites to antifolate therapy in many areas. In this context, we aimed to assess the worldwide genetic diversity of the P. malariae dhfr gene in 123 samples collected in Africa and Asia, areas with different histories of SP use. Among the 10 polymorphic sites found, we have observed 7 new mutations (K55E, S58R, S59A, F168S, N194S, D207G, and T221A), which led us to describe 6 new DHFR proteins. All isolates from African countries were classified as wild type, while new mutations and haplotypes were recognized as exclusive to Madagascar (except for the double mutations at nucleotides 341 and 342 [S114N] found in one Cambodian isolate). Among these nonsynonymous mutations, two were likely related to pyrimethamine resistance: S58R (corresponding to C59R in P. falciparum and S58R in Plasmodium vivax; observed in one Malagasy sample) and S114N (corresponding to S108N in P. falciparum and S117N in P. vivax; observed in three Cambodian samples). PMID:22123682

  11. Resistance Mechanisms and the Future of Bacterial Enoyl-Acyl Carrier Protein Reductase (FabI) Antibiotics.

    PubMed

    Yao, Jiangwei; Rock, Charles O

    2016-01-01

    Missense mutations leading to clinical antibiotic resistance are a liability of single-target inhibitors. The enoyl-acyl carrier protein reductase (FabI) inhibitors have one intracellular protein target and drug resistance is increased by the acquisition of single-base-pair mutations that alter drug binding. The spectrum of resistance mechanisms to FabI inhibitors suggests criteria that should be considered during the development of single-target antibiotics that would minimize the impact of missense mutations on their clinical usefulness. These criteria include high-affinity, fast on/off kinetics, few drug contacts with residue side chains, and no toxicity. These stringent criteria are achievable by structure-guided design, but this approach will only yield pathogen-specific drugs. Single-step acquisition of resistance may limit the clinical application of broad-spectrum, single-target antibiotics, but appropriately designed pathogen-specific antibiotics have the potential to overcome this liability. PMID:26931811

  12. 5α-Reductase-2 Deficiency: Clinical Findings, Endocrine Pitfalls, and Genetic Features in a Large Italian Cohort.

    PubMed

    Bertelloni, Silvano; Baldinotti, Fulvia; Russo, Gianni; Ghirri, Paolo; Dati, Eleonora; Michelucci, Angela; Moscuzza, Francesca; Meroni, Silvia; Colombo, Ilaria; Sessa, Maria R; Baroncelli, Giampiero I

    2016-01-01

    Clinical records (n = 24) with an established diagnosis of 5α-reductase-2 deficiency were reviewed. A previous misdiagnosis was present in about 70% (period from first observation to definitive diagnosis: 9.1 ± 10.8 years), and in 8 children gonadal removal was performed before certain diagnosis. Initial sex assignment was female in 16/24 (67%) and male in 8/24 (33%) cases. After diagnosis, sex re-assignment was performed in 5 babies (4 girls to male sex; 1 boy to female sex). Baseline testosterone/DHT ratio was diagnostic in 6/12 subjects (first months of life n = 4; puberty n = 2), while post-hCG testosterone/DHT ratio was diagnostic in all tested individuals (choosing both the cut-off value 15 or 10). Eighteen different mutations in the steroid-5α-reductase-2 (SRD5A2) gene were identified, 5 of which have never been reported. In conclusion, a time lag exists before the diagnosis of 5α-reductase-2 deficiency is established; sex assignment and gonadal removal may be performed before certain diagnosis. Sex re-assignment is usually female to male, but the contrary may occur. A large variability in clinical phenotypes and genetic mutations was present in this cohort. Accurate endocrine evaluation is recommended in babies possibly affected by 5α-reductase-2 deficiency, since the use of appropriate cut-off values of testosterone/DHT ratio after hCG stimulation may permit to select individuals for SRD5A2 gene analysis. A genotype-phenotype correlation was not found in this study. PMID:27070133

  13. MTHFR C677T is not a risk factor for autism spectrum disorders in South Brazil.

    PubMed

    dos Santos, Pollyanna Almeida Costa; Longo, Dânae; Brandalize, Ana Paula Carneiro; Schüler-Faccini, Lavínia

    2010-08-01

    Many studies have suggested that autism may be associated with metabolic abnormalities in the folate/homocysteine pathway, which is involved in DNA methylation, thus altering gene expression. One of the most important polymorphisms in this pathway is C677T of the methylenetetrahydrofolate reductase gene, because the T allele is associated with a decrease in enzymatic activity. We evaluated the association between C677T polymorphism and autism spectrum disorders through a case--control study. In addition, we analyzed the influence of this polymorphism on certain autistic behaviors like complex body movements, self-injury and averted gaze according to the Autism Diagnostic Interview-Revised. The analyses involved 151 children with idiopathic autism spectrum disorder and 100 healthy control children. The frequency of the T allele was 0.38 for the case group and 0.35 for the control group (P=0.77). The genotypic distribution did not show significant differences between cases and controls (P=0.72), nor association between the T allele and selected behaviors. PMID:20440228

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

    PubMed Central

    Carlus, S. Justin; Sarkar, Saumya; Bansal, Sandeep Kumar; Singh, Vertika; Singh, Kiran; Jha, Rajesh Kumar; Sadasivam, Nirmala; Sadasivam, Sri Revathy; Gireesha, P. S.; Thangaraj, Kumarasamy; Rajender, Singh

    2016-01-01

    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. PMID:26983014

  15. MTHFR 677T Is a Strong Determinant of the Degree of Hearing Loss Among Polish Males with Postlingual Sensorineural Hearing Impairment

    PubMed Central

    Pollak, Agnieszka; Mueller-Malesinska, Malgorzata; Lechowicz, Urszula; Skorka, Agata; Korniszewski, Lech; Sobczyk-Kopciol, Agnieszka; Waskiewicz, Anna; Broda, Grazyna; Iwanicka-Pronicka, Katarzyna; Oldak, Monika; Skarzynski, Henryk

    2012-01-01

    Hearing impairment (HI) is the most common sensory handicap. Congenital HI often has a genetic basis, whereas the etiology of nonsyndromic postlingual HI (npHI) usually remains unidentified. Our purpose was to test whether the MTHFR C677T (rs1801133) polymorphism affecting folate metabolism is associated with the occurrence or severity of npHI. We studied rs1801133 genotypes in 647 npHI patients (age <40, sudden sensorineural loss excluded, HI characterized as mean of better ear hearing thresholds for 0.5–8 kHz) and 3273 adult controls from the background population. Genotype distribution among patients and controls was similar, but among male cases (n=302) we found a dose-dependent correlation of MTHFR 677T with the degree of HI (mean thresholds in dB: 38.8, 44.9, and 53.3, for CC, CT, and TT genotypes, respectively; p=0.0013, pcor.=0.017). Among male patients rs1801133 TT significantly increased the risk of severe/profound HI (odds ratio=4.88, p=0.001). Among controls the known effect of MTHFR 677T on plasma total homocysteine was more pronounced in men than in women (p<0.00004 for genotype-sex interaction) suggesting that in Poland folate deficiency is more prevalent in males. In conclusion, we report a novel strong effect of MTHFR 677T among males with npHI. The functional significance of rs1801133 suggests that these patients may benefit from folate supplementation—an intervention which is simple, cheap, and devoid of side effects. PMID:22424391

  16. Influence of Nitrous Oxide Anesthesia, B-Vitamins, and MTHFR gene polymorphisms on Perioperative Cardiac Events: The Vitamins in Nitrous Oxide (VINO) Randomized Trial

    PubMed Central

    Nagele, Peter; Brown, Frank; Francis, Amber; Scott, Mitchell G.; Gage, Brian F.; Miller, J. Philip

    2013-01-01

    Background Nitrous oxide causes an acute increase in plasma homocysteine that is more pronounced in patients with the MTHFR C677T or A1298C gene variant. In this randomized controlled trial we sought to determine if patients carrying the MTHFR C677T or A1298C variant had a higher risk for perioperative cardiac events after nitrous oxide anesthesia and if this risk could be mitigated by B-vitamins. Methods We randomized adult patients with cardiac risk factors undergoing noncardiac surgery to receive nitrous oxide plus intravenous B-vitamins before and after surgery or to nitrous oxide and placebo. Serial cardiac biomarkers and 12-lead electrocardiograms were obtained. The primary study endpoint was the incidence of myocardial injury, as defined by cardiac troponin I elevation within the first 72 hours after surgery. Results A total of 500 patients completed the trial. Patients who were homozygous for either MTHFR C677T or A1298C gene variant (n= 98; 19.6%) had no increased rate of postoperative cardiac troponin I elevation compared to wild-type and heterozygous patients (11.2% vs. 14.0%; relative risk 0.96, 95% CI 0.85 to 1.07, p=0.48). B-vitamins blunted the rise in homocysteine, but had no effect on cardiac troponin I elevation compared to patients receiving placebo (13.2% vs. 13.6%; relative risk 1.02, 95% CI 0.78 to 1.32, p=0.91). Conclusions Neither MTHFR C677T and A1298C gene variant nor acute homocysteine increase are associated with perioperative cardiac troponin elevation after nitrousoxide anesthesia. B-vitamins blunt nitrous oxide-induced homocysteine increase but have no effect on cardiac troponin elevation. PMID:23856660

  17. Tales of Dihydrofolate Binding to R67 Dihydrofolate Reductase.

    PubMed

    Duff, Michael R; Chopra, Shaileja; Strader, Michael Brad; Agarwal, Pratul K; Howell, Elizabeth E

    2016-01-12

    Homotetrameric R67 dihydrofolate reductase possesses 222 symmetry and a single active site pore. This situation results in a promiscuous binding site that accommodates either the substrate, dihydrofolate (DHF), or the cofactor, NADPH. NADPH interacts more directly with the protein as it is larger than the substrate. In contrast, the p-aminobenzoyl-glutamate tail of DHF, as monitored by nuclear magnetic resonance and crystallography, is disordered when bound. To explore whether smaller active site volumes (which should decrease the level of tail disorder by confinement effects) alter steady state rates, asymmetric mutations that decreased the half-pore volume by ∼35% were constructed. Only minor effects on k(cat) were observed. To continue exploring the role of tail disorder in catalysis, 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide-mediated cross-linking between R67 DHFR and folate was performed. A two-folate, one-tetramer complex results in the loss of enzyme activity where two symmetry-related K32 residues in the protein are cross-linked to the carboxylates of two bound folates. The tethered folate could be reduced, although with a ≤30-fold decreased rate, suggesting decreased dynamics and/or suboptimal positioning of the cross-linked folate for catalysis. Computer simulations that restrain the dihydrofolate tail near K32 indicate that cross-linking still allows movement of the p-aminobenzoyl ring, which allows the reaction to occur. Finally, a bis-ethylene-diamine-α,γ-amide folate adduct was synthesized; both negatively charged carboxylates in the glutamate tail were replaced with positively charged amines. The K(i) for this adduct was ∼9-fold higher than for folate. These various results indicate a balance between folate tail disorder, which helps the enzyme bind substrate while dynamics facilitates catalysis. PMID:26637016

  18. Thermal Stabilization of Dihydrofolate Reductase Using Monte Carlo Unfolding Simulations and Its Functional Consequences

    PubMed Central

    Whitney, Anna; Shakhnovich, Eugene I.

    2015-01-01

    Design of proteins with desired thermal properties is important for scientific and biotechnological applications. Here we developed a theoretical approach to predict the effect of mutations on protein stability from non-equilibrium unfolding simulations. We establish a relative measure based on apparent simulated melting temperatures that is independent of simulation length and, under certain assumptions, proportional to equilibrium stability, and we justify this theoretical development with extensive simulations and experimental data. Using our new method based on all-atom Monte-Carlo unfolding simulations, we carried out a saturating mutagenesis of Dihydrofolate Reductase (DHFR), a key target of antibiotics and chemotherapeutic drugs. The method predicted more than 500 stabilizing mutations, several of which were selected for detailed computational and experimental analysis. We find a highly significant correlation of r = 0.65–0.68 between predicted and experimentally determined melting temperatures and unfolding denaturant concentrations for WT DHFR and 42 mutants. The correlation between energy of the native state and experimental denaturation temperature was much weaker, indicating the important role of entropy in protein stability. The most stabilizing point mutation was D27F, which is located in the active site of the protein, rendering it inactive. However for the rest of mutations outside of the active site we observed a weak yet statistically significant positive correlation between thermal stability and catalytic activity indicating the lack of a stability-activity tradeoff for DHFR. By combining stabilizing mutations predicted by our method, we created a highly stable catalytically active E. coli DHFR mutant with measured denaturation temperature 7.2°C higher than WT. Prediction results for DHFR and several other proteins indicate that computational approaches based on unfolding simulations are useful as a general technique to discover stabilizing mutations. PMID:25905910

  19. A high-throughput assay format for determination of nitrate reductase and nitrite reductase enzyme activities

    SciTech Connect

    McNally, N.; Liu, Xiang Yang; Choudary, P.V.

    1997-01-01

    The authors describe a microplate-based high-throughput procedure for rapid assay of the enzyme activities of nitrate reductase and nitrite reductase, using extremely small volumes of reagents. The new procedure offers the advantages of rapidity, small sample size-nanoliter volumes, low cost, and a dramatic increase in the throughput sample number that can be analyzed simultaneously. Additional advantages can be accessed by using microplate reader application software packages that permit assigning a group type to the wells, recording of the data on exportable data files and exercising the option of using the kinetic or endpoint reading modes. The assay can also be used independently for detecting nitrite residues/contamination in environmental/food samples. 10 refs., 2 figs.

  20. Transcripts of Anthocyanidin Reductase and Leucoanthocyanidin Reductase and Measurement of Catechin and Epicatechin in Tartary Buckwheat

    PubMed Central

    Kim, Yeon Bok; Thwe, Aye Aye; Kim, YeJi; Li, Xiaohua; Cho, Jin Woong; Park, Phun Bum; Valan Arasu, Mariadhas; Abdullah Al-Dhabi, Naif; Kim, Sun-Ju; Suzuki, Tastsuro; Hyun Jho, Kwang; Park, Sang Un

    2014-01-01

    Anthocyanidin reductase (ANR) and leucoanthocyanidin reductase (LAR) play an important role in the monomeric units biosynthesis of proanthocyanidins (PAs) such as catechin and epicatechin in several plants. The aim of this study was to clone ANR and LAR genes involved in PAs biosynthesis and examine the expression of these two genes in different organs under different growth conditions in two tartary buckwheat cultivars, Hokkai T8 and T10. Gene expression was carried out by quantitative real-time RT-PCR, and catechin and epicatechin content was analyzed by high performance liquid chromatography. The expression pattern of ANR and LAR did not match the accumulation pattern of PAs in different organs of two cultivars. Epicatechin content was the highest in the flowers of both cultivars and it was affected by light in only Hokkai T8 sprouts. ANR and LAR levels in tartary buckwheat might be regulated by different mechanisms for catechin and epicatechin biosynthesis under light and dark conditions. PMID:24605062

  1. Methylenetetrahydrofolate reductase genetic polymorphisms and toxicity to 5-FU-based chemoradiation in rectal cancer

    PubMed Central

    Thomas, F; Motsinger-Reif, A A; Hoskins, J M; Dvorak, A; Roy, S; Alyasiri, A; Myerson, R J; Fleshman, J W; Tan, B R; McLeod, H L

    2011-01-01

    Background: There is a large degree of variation in tumour response and host toxicities associated with neoadjuvant chemoradiation for rectal cancer patients. We performed a complimentary pharmacogenetic study to investigate germline polymorphisms of genes involved in 5-fluorouracil (5-FU) and irinotecan pathways and their potential association with clinical outcomes and toxicities from neoadjuvant chemoradiation in patients with rectal cancer treated in a prospective genotype-directed study. Methods: The germline DNA of 131 patients was genotyped for 10 variants in TYMS, MTHFR, DPYD, UGT1A1, ABCC1 and SLCO1B1 genes. Ninety-six patients were treated with 5-FU/radiotherapy (RT) and 35 received 5-FU/RT/irinotecan. Relationships between genetic variants and adverse events, tumour response, overall and disease-free survivals were assessed. Results: MTHFR 1298A>C and MTHFR diplotypes (for 677C>T and 1298A>C) were associated with chemoradiation-related toxicity when 5-FU was used alone. MTHFR haplotypes (677C–1298C) and diplotypes (CA–TA and TA–TA) showed, respectively, a protective and a negative effect on the incidence of severe diarrhoea or mucositis. No association was observed between genetic markers and drug response. Conclusion: MTHFR polymorphisms can potentially predict toxicity in patients treated with 5-FU as a single chemotherapeutic drug. PMID:22045187

  2. Ribonucleotide reductase metallocofactor: assembly, maintenance and inhibition

    PubMed Central

    ZHANG, Caiguo; LIU, Guoqi; HUANG, Mingxia

    2014-01-01

    Ribonucleotide reductase (RNR) supplies cellular deoxyribonucleotide triphosphates (dNTP) pools by converting ribonucleotides to the corresponding deoxy forms using radical-based chemistry. Eukaryotic RNR comprises α and β subunits: α contains the catalytic and allosteric sites; β houses a diferric-tyrosyl radical cofactor (FeIII2-Y•) that is required to initiates nucleotide reduction in α. Cells have evolved multi-layered mechanisms to regulate RNR level and activity in order to maintain the adequate sizes and ratios of their dNTP pools to ensure high-fidelity DNA replication and repair. The central role of RNR in nucleotide metabolism also makes it a proven target of chemotherapeutics. In this review, we discuss recent progress in understanding the function and regulation of eukaryotic RNRs, with a focus on studies revealing the cellular machineries involved in RNR metallocofactor biosynthesis and its implication in RNR-targeting therapeutics. PMID:24899886

  3. Monodehydroascorbate reductase mediates TNT toxicity in plants.

    PubMed

    Johnston, Emily J; Rylott, Elizabeth L; Beynon, Emily; Lorenz, Astrid; Chechik, Victor; Bruce, Neil C

    2015-09-01

    The explosive 2,4,6-trinitrotoluene (TNT) is a highly toxic and persistent environmental pollutant. Due to the scale of affected areas, one of the most cost-effective and environmentally friendly means of removing explosives pollution could be the use of plants. However, mechanisms of TNT phytotoxicity have been elusive. Here, we reveal that phytotoxicity is caused by reduction of TNT in the mitochondria, forming a nitro radical that reacts with atmospheric oxygen, generating reactive superoxide. The reaction is catalyzed by monodehydroascorbate reductase 6 (MDHAR6), with Arabidopsis deficient in MDHAR6 displaying enhanced TNT tolerance. This discovery will contribute toward the remediation of contaminated sites. Moreover, in an environment of increasing herbicide resistance, with a shortage in new herbicide classes, our findings reveal MDHAR6 as a valuable plant-specific target. PMID:26339024

  4. Domain Motion in Cytochrome P450 Reductase

    PubMed Central

    Ellis, Jacqueline; Gutierrez, Aldo; Barsukov, Igor L.; Huang, Wei-Cheng; Grossmann, J. Günter; Roberts, Gordon C. K.

    2009-01-01

    NADPH-cytochrome P450 reductase (CPR), a diflavin reductase, plays a key role in the mammalian P450 mono-oxygenase system. In its crystal structure, the two flavins are close together, positioned for interflavin electron transfer but not for electron transfer to cytochrome P450. A number of lines of evidence suggest that domain motion is important in the action of the enzyme. We report NMR and small-angle x-ray scattering experiments addressing directly the question of domain organization in human CPR. Comparison of the 1H-15N heteronuclear single quantum correlation spectrum of CPR with that of the isolated FMN domain permitted identification of residues in the FMN domain whose environment differs in the two situations. These include several residues that are solvent-exposed in the CPR crystal structure, indicating the existence of a second conformation in which the FMN domain is involved in a different interdomain interface. Small-angle x-ray scattering experiments showed that oxidized and NADPH-reduced CPRs have different overall shapes. The scattering curve of the reduced enzyme can be adequately explained by the crystal structure, whereas analysis of the data for the oxidized enzyme indicates that it exists as a mixture of approximately equal amounts of two conformations, one consistent with the crystal structure and one a more extended structure consistent with that inferred from the NMR data. The correlation between the effects of adenosine 2′,5′-bisphosphate and NADPH on the scattering curve and their effects on the rate of interflavin electron transfer suggests that this conformational equilibrium is physiologically relevant. PMID:19858215

  5. Hexaheme nitrite reductase from Desulfovibrio desulfuricans

    SciTech Connect

    Costa, C.; Moura, J.J.G.; Moura, I. Univ. Nova de Lisboa, Oeiras ); Liu, M.Y.; Peck, H.D. Jr.; LeGall, J. ); Wang, Yaning; Huynh, B.H. )

    1990-08-25

    Moessbauer and EPR spectroscopy were used to characterize the heme prosthetic groups of the nitrite reductase isolated from Desulfovibrio desulfuricans (ATCC 27774), which is a membrane-bound multiheme cytochrome capable of catalyzing the 6-electron reduction of nitrite to ammonia. At pH 7.6, the as-isolated enzyme exhibited a complex EPR spectrum consisting of a low-spin ferric heme signal at g = 2.96, 2.28, and 1.50 plus several broad resonances indicative of spin-spin interactions among the heme groups. EPR redox titration studies revealed yet another low-spin ferric heme signal at g = 3.2 and 2.14 (the third g value was undetected) and the presence of a high-spin ferric heme. Moessbauer measurements demonstrated further that this enzyme contained six distinct heme groups: one high-spin (S = 5/2) and five low-spin (S = 1/2) ferric hemes. Characteristic hyperfine parameters for all six hemes were obtained through a detailed analysis of the Moessbauer spectra. D. desulfuricans nitrite reductase can be reduced by chemical reductants, such as dithionite or reduced methyl viologen, or by hydrogenase under hydrogen atmosphere. Addition of nitrite to the fully reduced enzyme reoxidized all five low-spin hemes to their ferric states. The high-spin heme, however, was found to complex NO, suggesting that the high-spin heme could be the substrate binding site and that NO could be an intermediate present in an enzyme-bound form.

  6. The cytochrome bd respiratory oxygen reductases

    PubMed Central

    Borisov, Vitaliy B.; Gennis, Robert B.; Hemp, James; Verkhovsky, Michael I.

    2011-01-01

    Summary Cytochrome bd is a respiratory quinol:O2 oxidoreductase found in many prokaryotes, including a number of pathogens. The main bioenergetic function of the enzyme is the production of a proton motive force by the vectorial charge transfer of protons. The sequences of cytochromes bd are not homologous to those of the other respiratory oxygen reductases, i.e., the heme-copper oxygen reductases or alternative oxidases (AOX). Generally, cytochromes bd are noteworthy for their high affinity for O2 and resistance to inhibition by cyanide. In E. coli, for example, cytochrome bd (specifically, cytochrome bd-I) is expressed under O2-limited conditions. Among the members of the bd-family are the so-called cyanide-insensitive quinol oxidases (CIO) which often have a low content of the eponymous heme d but, instead, have heme b in place of heme d in at least a majority of the enzyme population. However, at this point, no sequence motif has been identified to distinguish cytochrome bd (with a stoichiometric complement of heme d) from an enzyme designated as CIO. Members of the bd-family can be subdivided into those which contain either a long or a short hydrophilic connection between transmembrane helices 6 and 7 in subunit I, designated as the Q-loop. However, it is not clear whether there is a functional consequence of this difference. This review summarizes current knowledge on the physiological functions, genetics, structural and catalytic properties of cytochromes bd. Included in this review are descriptions of the intermediates of the catalytic cycle, the proposed site for the reduction of O2, evidence for a proton channel connecting this active site to the bacterial cytoplasm, and the molecular mechanism by which a membrane potential is generated. PMID:21756872

  7. Key Residues Regulating the Reductase Activity of the Human Mitochondrial Apoptosis Inducing Factor.

    PubMed

    Villanueva, Raquel; Ferreira, Patricia; Marcuello, Carlos; Usn, Alejandro; Miramar, M Dolores; Peleato, M Luisa; Lostao, Anabel; Susin, Santos A; Medina, Milagros

    2015-08-25

    The human Apoptosis Inducing Factor (hAIF) is a bifunctional NAD(P)H-dependent flavoreductase involved in both mitochondrial energy metabolism and caspase-independent cell death. Even though several studies indicate that both functions are redox controlled by NADH binding, the exact role of hAIF as a reductase in healthy mitochondria remains unknown. Upon reduction by NADH, hAIF dimerizes and produces very stable flavin/nicotinamide charge transfer complexes (CTC), by stacking of the oxidized nicotinamide moiety of the NAD(+) coenzyme against the re-face of the reduced flavin ring of its FAD cofactor. Such complexes are critical to restrict the hAIF efficiency as a reductase. The molecular basis of the hAIF