Polimorfismo de proteína 5, 10-metilentetrahidrofolatoreductasa en población venezolana / Polymorphisms proteína 5, 10-metilentetrahidrofolatoreductasa in venezuelan people

El folato es un miembro del grupo de la vitamina B y está relacionado con enfermedades crónicas como anemia megaloblástica, enfermedad cardiovascular, cáncer, disfunción cognitiva y riesgo de defectos del tubo neural. La proteína 5,10-metilentetrahidrofolato reductasa (MTHFR) juega un papel clave en el metabolismo del folato mediante la síntesis de nucleótidos y reacciones de metilación. El gen MTHFR se encuentra en el cromosoma 1 (1p36.3), y se han descrito dos alelos comunes, el alelo C677T (termolábil) y el alelo A1298C.El objetivo de este estudio es evaluar la distribución de los polimorfismos genéticos en MTHFR C677T y A1298C en la población venezolana. METODOS: estudio de tipo transversal, descriptivo, experimental y correlacional Las muestras de sangre se colectaron en 314 donantes no emparentados y sanos de la población. Los polimorfismos de un solo nucleótido(SNP) MTHFR 677C>T y 1298A>C se analizaron mediante polimorfismo de longitud de fragmento de restricción de reacción en cadena de polimerasa (PCR-RFLP). El desequilibrio de ligamiento (LD) entre pares de SNP se calculó mediante la prueba X. usando Prism 5 (GraphPad software, Inc). RESULTADOS: Encontramos mayor frecuencia genotípica de heterocigotos para el polimorfismo MTHFR C677T en la población general venezolana, con excepción del grupo caucásico. El polimorfismo MTHFR A1298C en el 70%de la población de estudio es homocigoto de tipo salvaje, encontrándose una baja frecuencia de homocigoto mutado. CONCLUSIONES: Se encontraron diferencias significativas entre grupos étnicos, destacando la importancia del genotipado racial de estos polimorfismos en la población venezolana(AU)

Folate is a member of the vitamin B and it has also been indicated that may be related to chronic diseases such as megaloblastic anemia, cardiovascular disease, cognitive dysfunction and risk of neural tube. Methylenetetrahydro folatereductase (MTHFR) is a key enzyme of folate pathway by nucleotide synthesis and methylation reactions. Several polymorphisms were reported in MTHFR gene but C677Tand A1298 polymorphism are most studied and these have been reported to be risk factor for several diseases/disorders. The present study was designed to determine the frequency of MTHFR polymorphisms in Venezuelan healthy population. METHODS: The blood samples were collected from 314 unrelated and healthy donors from population. Both the MTHFR 677C>T and 1298A>C single nucleotide polymorphisms (SNPs) were analyzed by Polymerase chainreaction-restriction fragment length polymorphism (PCR-RFLP). Linkage disequilibrium (LD) between pair of SNPs was calculated through the .. test using Prism 5 (GraphPad sftoware, Inc). RESULTS: We find higher genotypic frequency of heterozygotes for the MTHFR C677T polymorphism in the Venezuelan general population, with the exception of the Caucasian group. MTHFR A1298C polymorphism in 70%of the study population is homozygous wild type, finding alow frequency of homozygous mutated. CONCLUSIONS: Significant differences between ethnic groups were found,highlighting the importance of racial genotyping of these polymorphisms in the Venezuelan population(AU)

Screening of six polymorphisms related with folate metabolism in parents of individuals with Down syndrome.

OBJECTIVE: The study aim to investigate MTHFR C677T, MTHFR A1298C, RFC1 A80G, MTR A2756G, CBS 844ins68, MTRR A66G polymorphisms in Down syndrome (DS) parents. METHODS: Polymorphisms were evaluated in 35 mothers and 24 fathers of individuals with free trisomy of chromosome 21 confirmed by karyotype. The control group included 26 mothers and 26 fathers who had no children with DS. The molecular analysis was performed by polymerase chain reaction and restriction fragment length polymorphism (reaction chain polymerase restriction fragment length polymorphism) or polymerase chain reaction. The χ2 test (chi-square) was used to compare allele's differences among the study and the control group. Hardy-Weinberg equilibrium model was performed by χ2 testing. Multiple logistic regression models and binary logistic regression used to determine the association between polymorphisms and parental DS risk. RESULTS: This study did not reveal any significant difference in frequencies of polymorphisms. The haplotype analysis did not reveal linkage disequilibrium. The logistic regression analysis did not demonstrate differences between the groups. However, the binary logistic regression showed a higher frequency of the polymorphic homozygote genotype in DS parent group to codominant and dominant model in the RFC1 A80G. CONCLUSION: In conclusion, although the screening results were significant only to the RFC1 A80G polymorphism, the other determinations of the genetic factors associated with abnormal chromosome segregation could be helpful in future studies, including other polymorphisms involved in folate metabolism.

Trombosis senovenosa cerebral en un recién nacido con mutación MTHFR C677T tratado con enoxaparina / Cerebral sinovenous thrombosis in a newborn with mutation of MTHFR C677T treated with enoxaparin

Resumen: Introducción: La trombosis senovenosa cerebral neonatal (TSVC), es una patología rara y generalmente grave, de la cual se conoce poco sobre los mecanismos fisiopatológicos responsables y, aunque controvertido, se ha sugerido que la trombofilia genética, puede desempeñar un rol en la patogénesis. Debido a los temores de un sangrado intracraneal el tratamiento anticoagulante con heparina de bajo peso mole cular es controvertido. Objetivo: presentar un recién nacido con una trombosis senovenosa cerebral neonatal, discutir los factores de riesgo trombofílico, y el manejo con heparina de bajo peso molecu lar de la trombosis venosa cerebral. Caso Clínico: Recién nacido de término que debutó a los 8 días de vida con convulsiones clónicas, rechazo al pecho más hipoactividad motora. La neuroimagen con RM mostró una TSVC involucrando múltiples senos venosos, un infarto hemorrágico talámico dere cho y congestión venosa de la sustancia blanca frontal. El estudio de trombofilia puso de relieve una mutación homocigota del gen MTHFR C677T. El tratamiento con heparina de bajo peso molecular se asoció a repermeabilización del seno sagital superior a los 23 días de iniciada la terapia. Conclusio nes: La presentación clínica de la TSVC en el neonato es inespecífica, probablemente en relación con la extensión y gravedad de la lesión y el desarrollo de complicaciones asociadas, como infartos he morrágicos venosos intraparenquimatosos o hemorragia intraventricular. Estas complicaciones son detectables mediante Ecografia o Resonancia Magnética, y deben hacer sospechar una TSVC. En esta experiencia el tratamiento anticoagulante mostró ser seguro y prevenir la extensión de la trombosis.

Abstract: Introduction: Neonatal cerebral sinovenous thrombosis (CSNT) is a rare and generally serious con dition about which there is little knowledge of the responsible pathophysiological mechanisms and, although controversial, it has been suggested that genetic thrombophilia may play a role in its patho genesis. Out of concern for intracranial bleeding, the anticoagulant treatment with low-molecular- weight heparin is controversial. Objective: To present a case of a newborn with neonatal CSNT, to analyze the thrombophilic risk factors, and the management of cerebral venous thrombosis with low-molecular-weight heparin. Clinical Case: Full-term newborn who presented at eight days of life breastfeeding rejection, clonic seizures, and locomotor hypoactivity. The MRI neuroimaging showed a CSNT involving multiple venous sinuses, a right thalamic hemorrhagic infarction, and venous congestion in frontal white matter. Thrombophilia study highlighted a homozygous MTHFR C677T mutation. Treatment with low-molecular-weight heparin was associated with repermeabilization of the superior sagittal sinus after 23 days of starting therapy. Conclusions: The clinical presentation of CSNT in the neonate is nonspecific, probably related to the extent and severity of the injury and the development of associated complications, such as venous hemorrhagic infarctions and intraparenchymal or intraventricular hemorrhage. These complications are detected through ultrasound or MRI, and they should make us suspect a CSNT. In this experience, the anticoagulant treatment proved to be safe and prevents thrombus propagation.

Lack of association between methylenetetrahydrofolate reductase C677T polymorphism, HPV infection and cervical intraepithelial neoplasia in Brazilian women.

BACKGROUND: Cervical cancer has high prevalence and mortality rates in worldwide female population. Persistent infection by high-risk Human Papillomavirus (hr-HPV) is the main cause of this cancer. However, many environmental, genetical, and epigenetical cofactors can modulate viral infection and cervical carcinogenesis. Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism is a genetic factor that has been associated with many pathologies, including cancer. Nevertheless, studies with cervical cancer presented controversial results, and varied according to ethnicity. Thus, the aim of this study was to determine association between MTHFR C677T polymorphism, Human Papillomavirus (HPV) infection and cervical cancer. METHODS: A case-control study was performed with 150 histological cervical samples. Case group were divided in Cervical Intraepithelial Neoplasia (CIN) grade I (n = 30), CIN II (n = 30), CIN III (n = 30), and Squamous Cervical Carcinoma (SCC) (n = 30). Control group was composed by 30 samples without lesion, presenting cervicitis. HPV detection was performed by conventional Polymerase Chain Reaction (PCR) with SPF primers set, and by real-time PCR specific for HPV 16 and hr-HPV. MTHFR C677T polymorphism was analyzed by PCR followed by Restriction Fragment Length Polymorphism (RFLP). RESULTS: Frequency of MTHFR CC genotype was 72.7% (n = 109), CT 23.3% (n = 35) and TT 4.0% (n = 6). Polymorphic T allele frequency was 15.7%. No statistically significant association was observed between MTHFR C677T polymorphism and presence of pre-neoplastic or neoplastic cervical lesions. Similar frequencies of T allele was observed in control (23.3%) and cases (13.3%) groups (p = 0.174). In addition, there was no statistically significant association between MTHFR C677T polymorphism and viral infection, even considering hr-HPV or HPV 16 positivity. CONCLUSION: MTHFR C677T polymorphism was not associated with cervical cancer and HPV infection.

The influence of MTHFR C677T polymorphism in chronic lymphocytic leukemia.

Some factors have been associated with the etiology of chronic lymphocytic leukemia (CLL), among them the Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism. The aim of this study was to evaluate the role of MTHFR C677T polymorphism in CLL. A case-control study was conducted with 219 individuals from Brazilian central population. MTHFR C677T polymorphism was determined through PCR-RFLP followed by PAGE. The T allele frequence was higher in patients diagnosed with CLL than healthy subjects. However, when stratified by gender, the TT genotype was exclusively found in men diagnosed with CLL (p < 0.05). Adjusted multiple logistic regression analysis demonstrated that age was significantly linked to CLL predisposition (odds ratio = 1.08; p < 0.001). Studies evaluating the influence of genetic factors may provide insights on susceptibility for CLL.

Polymorphisms C677T and A1298C of MTHFR Gene: Homocysteine Levels and Prothrombotic Biomarkers in Coronary and Pulmonary Thromboembolic Disease.

The activity of the enzyme methylenetetrahydrofolate reductase (MTHFR) determines homocysteine (Hcy) levels, and polymorphisms in its gene affect the activity of the enzyme. Changes in the enzyme's activity may lead to a higher susceptibility to develop arterial and venous thromboembolic disease. The aim was to analyze the relationship between the C677T and A1298C polymorphisms of MTHFR, Hcy levels, and prothrombotic biomarkers in pulmonary embolism (PE) and acute myocardial ischemia (AMI). Clinical files of patients with thromboembolic diseases having complete data and whose doctor had requested an assay to determine the polymorphisms of the MTHFR gene, Hcy levels, and prothrombotic biomarkers were studied to search for the correlation between mutations of the MTHFR gene and Hcy levels in the different diseases. We included 334 files: 158 were from women and 176 from men (51 [19 SD] years). Sixty-three percent have had thrombosis, 8% AMI, and 31% PE. Patients with thrombosis had elevated frequency of the C677T polymorphism. The CC genotype was higher than the TT genotype ( P = .003) and CT versus the TT ( P = .009). In patients with PE, the CC genotype was higher than the TT genotype ( P = .038). Pulmonary embolism with massive and submassive events had predominant genotypes 677 TT ( P = .003) and the AA 1298 ( P = .017). Elevated Hcy levels in the presence of the T allele in the C677T gene and of the A allele in the A1298C gene are associated with AMI and massive and submassive PE.

Comparison of Capillary Electrophoresis, AGE, and PAGE for MTHFR Polymorphism Analysis in FFPE Cervical Samples.

BACKGROUND: Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism analysis could help in diagnosis, treatment, and prognosis of some pathologies, since it has been associated with the development of cardiovascular diseases, defects in neural tube formation, psychiatric disorders, and cancer. Polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP) is the most commonly used technique to analyze this polymorphism. Usually, RFLP products are evaluated by agarose gel electrophoresis (AGE) or polyacrylamide gel electrophoresis (PAGE). However, capillary electrophoresis (CE) may represent an alternative for MTHFR C677T polymorphism analysis by PCR-RFLP. Thus, the aim of this study was to compare CE, AGE, and PAGE to MTHFR C677T polymorphism analysis of Formalin-Fixed and Paraffin-Embedded (FFPE) cervical samples. METHODS: 150 biopsy blocks of cervical samples were analyzed. MTHFR polymorphism was evaluated by PCR-RFLP, and the products generated were analyzed by CE, AGE, and PAGE. Concordance between the methods was evaluated by rate agreement, Kappa coefficient, and McNemars's Test. RESULTS: Eight samples (5.4%) showed discordant results according to CE and PAGE or AGE. Differences of CC and CT frequencies were observed between CE and AGE (p=0.016): CC genotype varied from 68.0% to 72.7%, and CT varied from 23.3% to 27.3%. Besides, Kappa coefficient between CE and AGE, or PAGE was very high (κ>0.81). CONCLUSION: Capillary electrophoresis presented high agreement with PAGE and AGE, and may be an accurate, safe, and quick alternative method for MTHFR polymorphism analysis.

Influence of the C677T Polymorphism of the MTHFR Gene on Oxidative Stress in Women With Overweight or Obesity: Response to a Dietary Folate Intervention.

The C677T polymorphism of the methylenetetrahydrofolate reductase gene (MTHFR) is related to folate metabolism and can alter the levels of biochemical markers.Objective: Investigate the influence of the MTHFR C677T polymorphism on the effects of a dietary folate intervention on oxidative stress in women with overweight or obesity.Methods: Forty-eight adult women with overweight or obesity were subjected to a 24-hour dietary recall, anthropometric measurements, biochemical analysis, and genotyping of the MTHFR C677T polymorphism. They were allocated by convenience sampling to 2 groups, which received 300 g of folate-rich vegetables containing 191 µg/d (Group 1) (n = 24) or 95 µg/d (Group 2) (n = 24) of folate for 8 weeks.Results: The dietary intervention increased the serum folic acid levels in the 2 analyzed groups. The intervention with 191 µg/d of folate led to relevant results in terms of homocysteine levels (p = 0.0005) and total antioxidant capacity (p = 0.0261); the effect was larger among carriers of the TT genotype.Conclusions: The study demonstrated the beneficial effect of folate intake in terms of a TAC elevation for the CC and TT genotypes of the MTHFR C677T polymorphism, an increase in folic acid levels for all genotypes, and a reduction in the Hcy levels for the TT genotype in response to an intervention consisting of an intake of 191 µg/d of folate supplied by vegetables.

Prevalence of the MTHFR C677T Mutation in Fertile and Infertile Women / Prevalência da mutação MTHFR C677T em mulheres férteis e inférteis

Abstract Introduction The importance of the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene in infertile women remains controversial. Objective To evaluate if the MTHFR C677T mutations are more frequent in infertile women, and if they can be associated with the occurrence of infertility in the Brazilian population. Methods This case-control study included 130 infertile women consulting at a private clinic betweenMarch 2003 andMarch 2005 (data previously published), and 260 fertile women attending the family planning outpatient clinic of our institution between April 2012 and March 2013. Data analysis The Chi-squared and Fisher Exact tests were used to evaluate the association between the presence of the MTHFR C677T mutation and a history of infertility. Results The frequency of the mutation was of 58.5% for the case group (n = 76) and of 49.2% for the fertile controls (n = 128). The mutation was homozygous in 13 women in the case group (10%) and in 23 of the fertile women in the control group (8.8%). These differences were not statistically significant. Conclusions These results suggest that the presence of the MTHFR C677T mutation does not constitute a risk factor for infertility, even when themutation is homozygous. Further studies are needed to confirm whether research on this mutation should be considered unnecessary in women with infertility.

Resumo Introdução A importância da mutação C677T no gene da metilenotetrahidrofolato redutase (MTHFR) em mulheres com infertilidade permanece controversa. Objetivo Avaliar se a mutação MTHFR C677Témais frequente em mulheres inférteis, e se pode ser associada com a ocorrência de infertilidade na população brasileira. Métodos Estudo de caso-controle, com avaliação de 130 mulheres com infertilidade atendidas em clínica privada no período de março de 2003 a março de 2005 (dados previamente publicados) e 260 mulheres férteis atendidas no ambulatório de planejamento familiar de nossa instituição no período de abril de 2012 a março de 2013. Análise dos dados Foram utilizados os testes de Qui-quadrado e Exato de Fisher para o estudo da associação entre a presença damutação MTHFR C677T e o antecedente de infertilidade. Resultados A frequência da mutação foi de 58,5% nos casos (n = 76) e de 49,2% nos controles (n = 128). Dentre os casos, 13 apresentavam esta mutação em homozigose (10%). Nos controles, a homozigose foi encontrada em 23 mulheres férteis (8,8%). Estas diferenças não foram estatisticamente significativas. Conclusões Este estudo sugere que a presença da mutação MTHFR C677T não constitui fator de risco para infertilidade, mesmo em casos de homozigose. Estudos complementares são necessários para ratificar se a investigação desta mutação deve ser considerada desnecessária em mulheres com infertilidade.

Tailoring Nutritional Advice for Mexicans Based on Prevalence Profiles of Diet-Related Adaptive Gene Polymorphisms.

Diet-related adaptive gene (DRAG) polymorphisms identified in specific populations are associated with chronic disorders in carriers of the adaptive alleles due to changes in dietary and lifestyle patterns in recent times. Mexico's population is comprised of Amerindians (AM) and Mestizos who have variable AM, European (EUR) and African genetic ancestry and an increased risk of nutrition-related chronic diseases. Nutritional advice based on the Mexican genome and the traditional food culture is needed to develop preventive and therapeutic strategies. Therefore, we aimed to provide a prevalence profile of several DRAG polymorphisms in the Mexican population, including Central West (CW) Mexico subpopulations. Geographic heat maps were built using ArcGIS10 (Esri, Redlands, CA, USA) software, based on the published data of the MTHFR C677T (rs1801133), ABCA1 Arg230Cys (rs9282541), APOE T388C (rs429358)/C526T (rs7412), LCT C-13910T (rs4988235) polymorphisms and AMY1 copy number variation (CNV). Also, new data obtained by allelic discrimination-real-time polymerase chain reaction (RT-PCR) assays for the MTHFR, ABCA1, and APOE polymorphisms as well as the AMY1 CNV in the CW Mexico subpopulations with different proportions of AM and EUR ancestry were included. In the CW region, the highest frequency of the MTHFR 677T, ABCA1 230C and APOE ε4 adaptive alleles was observed in the AM groups, followed by Mestizos with intermediate AM ancestry. The LCT-13910T allele frequency was highest in Mestizos-EUR but extremely low in AM, while the AMY1 diploid copy number was 6.82 ± 3.3 copies. Overall, the heat maps showed a heterogeneous distribution of the DRAG polymorphisms, in which the AM groups revealed the highest frequencies of the adaptive alleles followed by Mestizos. Given these genetic differences, genome-based nutritional advice should be tailored in a regionalized and individualized manner according to the available foods and Mexican traditional food culture that may lead to a healthier dietary pattern.

Influence of vitamin intake and MTHFR polymorphism on the levels of DNA damage in tobacco farmers.

BACKGROUND: Genetic damage may occur spontaneously under normal metabolic circumstances, inadequate intake of nutrients, and excessive exposure to environmental mutagens. OBJECTIVES: To evaluate the influence of the intake of micronutrients vitamin B12, vitamin B6, and folate and of the polymorphism methylenetetrahydrofolate reductase (MTHFR) C677T on the induction of DNA damage in tobacco farmers. METHODS: The study involved 66 men and 44 women engaged in tobacco cultivation in the region of Venâncio Aires (Rio Grande do Sul state, Brazil). Peripheral blood samples were collected to analyze DNA damage using the Comet assay, the micronucleus (MN) test and MTHFR C677T polymorphism. Dietary intake was evaluated based on the mean values obtained from three 24-h diet recall questionnaires, and nutrient intake data were computerized and estimated in the Food Processor SQL 10.9 program. The statistical tests used to generate the stated results were Kruskal-Wallis test, Exact Fisher's test, and multivariate linear regression analysis. RESULTS: DNA damage was significantly higher in individuals who had an inadequate intake of folate, vitamin B12, and vitamin B6 (P < 0.01) assessed by Comet assay. In relation to MN test results, buccal cells showed MN frequency higher in individuals with inadequate intake of vitamin B6 (P < 0.01). No difference was observed in MN lymphocytes frequency. No significant association was detected between MTHFR C677T polymorphism and DNA damage in tobacco farmers. CONCLUSION: Our results suggest that folate, vitamin B12, and vitamin B6 deficiency may be associated with genotoxic effect in individuals exposed to pesticides.

Methylene tetrahydrofolate reductase, transforming growth factor-ß1 and lymphotoxin-α genes polymorphisms and susceptibility to rheumatoid arthritis.

BACKGROUND: Rheumatoid arthritis is a widely prevalent autoimmune disorder with suggested genetic predisposition. OBJECTIVES: The aim of this study is to detect the pattern of genetic polymorphism of methylene tetrahydrofolate reductase (MTHFR C677 T and A1298 C), transforming growth factor-ß1 (TGF-ß1 T869 C) and lymphotoxin-α (LT-α A252G) in patients having rheumatoid arthritis and correlate these patterns to disease activity and serum levels of tumor necrosis factor-alpha (TNF-α), B-Cell Activating Factor (BAFF), and osteopontin. METHODS: A total of 194 subjects, 90 controls and 104 patients with rheumatoid arthritis were genotyped for MTHFR C677 T and A1298 C, TGF-ß1 T869 C and LT-α A252G polymorphisms using a methodology based on PCR-RFLP. Also serum levels of TNF-α, osteopontin and BAFF were measured by ELISA kits. RESULTS: The CT genotype and T allele of MTHFR C677 T and GG genotype and G allele of LT-α A252G are associated with the risk of RA and with higher levels of the pro-inflammatory cytokine, TNF-α in patients with rheumatoid arthritis. CONCLUSION: Our findings suggest that there is association between MTHFR C677 T and LT-α A252G genes polymorphisms and increased risk of RA in this sample of Egyptian population.

Methylene tetrahydrofolate reductase, transforming growth factor-ß1 and lymphotoxin-α genes polymorphisms and susceptibility to rheumatoid arthritis / Polimorfismos dos genes metilenotetrahidrofolato redutase, fator de crescimento transformador β1 e linfotoxina-α e susceptibilidade à artrite reumatoide

ABSTRACT Background: Rheumatoid arthritis is a widely prevalent autoimmune disorder with suggested genetic predisposition. Objectives: The aim of this study is to detect the pattern of genetic polymorphism of methylene tetrahydrofolate reductase (MTHFR C677 T and A1298 C), transforming growth factor-β1 (TGF-β1 T869 C) and lymphotoxin-α (LT-α A252G) in patients having rheumatoid arthritis and correlate these patterns to disease activity and serum levels of tumor necrosis factor-alpha (TNF-α), B-Cell Activating Factor (BAFF), and osteopontin. Methods: A total of 194 subjects, 90 controls and 104 patients with rheumatoid arthritis were genotyped for MTHFR C677 T and A1298 C, TGF-β1 T869 C and LT-α A252G polymorphisms using a methodology based on PCR-RFLP. Also serum levels of TNF-α, osteopontin and BAFF were measured by ELISA kits. Results: The CT genotype and T allele of MTHFR C677 T and GG genotype and G allele of LT-α A252G are associated with the risk of RA and with higher levels of the pro-inflammatory cytokine, TNF-α in patients with rheumatoid arthritis. Conclusion: Our findings suggest that there is association between MTHFR C677 T and LT-α A252G genes polymorphisms and increased risk of RA in this sample of Egyptian population.

RESUMO Antecedentes: A artrite reumatoide é uma doença autoimune amplamente prevalente com sugerida predisposição genética. Objetivos: Detectar o padrão de polimorfismo dos genes metilenotetrahidrofolato redutase (MTHFR C677 T e A1298 C), fator de crescimento transformador β1 (TGF-β1 T869 C) e linfotoxina-α (LT-α A252G) em pacientes com artrite reumatoide e correlacionar esses padrões com a atividade da doença e os níveis séricos de fator de necrose tumoral alfa (TNF-α), fator ativador de linfócitos B (BAFF) e osteopontina. Métodos: Foram genotipados 194 indivíduos – 90 controles e 104 com artrite reumatoide – à procura de polimorfismos dos genes MTHFR C677 T e A1298 C, TGF-β1 T869 C e LT-α A252G com uma metodologia baseada na PCR-RFLP. Mensuraram-se também os níveis séricos de TNF-α, osteopontina e BAFF com kits de Elisa. Resultados: O genótipo CT e o alelo T do MTHFR C677 T e o genótipo GG e alelo G do LT-α A252G estão associados ao risco de AR e a níveis mais elevados da citocina pró-inflamatória TNF-α em pacientes com artrite reumatoide. Conclusão Os achados do presente estudo sugerem que há associação entre os polimorfismos dos genes MTHFR C677 T e LT-α A252G e um risco aumentado de AR nessa amostra da população egípcia.

TGFBR2 mutation and MTHFR-C677T polymorphism in a Mexican mestizo population with cervico-cerebral artery dissection.

Spontaneous cervico-cerebral artery dissection (CCAD) is a common condition found among young patients with ischemic stroke. We examined the possible association between the polymorphism of methylenetetrahydrofolate reductase (MTHFR)-C677T and the gene mutation in transforming growth factor beta receptor II (TGFBR2) in a cohort of CCAD patients. One-hundred CCAD cases (65 males; mean age: 38.08 ± 10.68 years) and 100 matching controls were included. Ancestry informative markers (AIMs) were used to increase internal validity of the genetic analysis. Genotypes of the C677T polymorphism in the MTHFR gene were determined by polymerase chain reaction and restriction fragment length polymorphism; direct sequencing was used for a mutation analysis of the TGFBR2 gene. Associations were evaluated using a multivariate statistics, and Hardy-Weinberg equilibrium was analyzed. We also incorporated our data into a meta-analysis of the MTHFR-C677T. Sixty-three patients presented with vertebral and 37 with carotid artery dissection. Ancestry markers found a call rate on each over 95 %. All AIMs did not deviate from Hardy-Weinberg equilibrium (p > 0.05). The homozygous TT genotype was more frequent in cases (OR 2.04, CI 95 % 1.53-2.72, p = 0.005), whereas no significant difference was found on heterozygous CT genotype. TGFBR2 mutation was not present in our samples. In the meta-analysis of MTHFR/C677T variant, a total 613 cases and 1547 controls were analyzed; we found a moderate association for the recessive model genotype (OR 2.04, CI 95 % 1.53-2.72; p = 0.342; Z = 4.83; I (2) = 11.3). This study supports a positive association between the MTHFR-C677T polymorphism and genetically confirmed Mexican mestizo CCAD patients.

Polimorfismo C677T de la enzima 5, 10-metilenetetrahidrofolato reductasa (MTHFR) y enfermedad cardiovascular / C677T polymorphism of 5, 10-methylenetetrahydrofolate reductase (MTHFR) and cardiovascular disease

Introducción: existe evidencia sobre la relación entre niveles elevados de homocisteína (Hcy) en plasma y riesgo de enfermedad cardiovascular (ECV). El polimorfismo C677T del gen que codifica la enzima 5,10-metilenetetrahidrofolato reductasa (MTHFR) es considerado un determinante genético para la concentración de homocisteína. Vitaminas como el ácido fólico, B12, B2 y B6 participan en el metabolismo de este aminoácido. Objetivo: explorar la evidencia bibliográfica sobre el polimorfismo C677T, el riesgo de enfermedad cardiovascular y aquellos nutrientes que puedan prevenirla.Materiales y Método: se realizó una búsqueda de publicaciones en bases de datos electrónicas MEDLINE, EMBASE y Google académico. Se incluyeron aquellos artículos que contenían las palabras claves o una combinación de ellas, durante 1994-2015. Resultados: 15 artículos fueron incluidos. Se evidenció un aumento del riesgo de ECV en portadores del polimorfismo C677T. El ácido fólico es un importante determinante de la concentración de Hcy en plasma. Portadores homocigotos TT mostraron una disminución del nivel de Hcy en respuesta a la suplementación con vitaminas B12, B2 y B6.Conclusión: los trabajos analizados mostraron la relación entre la menor actividad de la enzima MTHFR, el incremento de Hcy y el riesgo de ECV. Los valores de Hcy en plasma se vieron influenciados por deficiencias de vitaminas del grupo B, siendo éstas un importante determinante de su concentración plasmática en el genotipo TT.

Polimorfismo C677T del gen de la metilentetrahidrofolato reductasa en madres de niños afectados con defectos del tubo neural / C677T polymorphism of the methylentetrahydrofolate reductase gene in mothers of children affected with neural tube defects.

Los defectos del tubo neural (DTN) son las alteraciones congénitas más frecuentes del sistema nervioso central. El mecanismo de transmisión hereditario de los DTN aislados es multifactorial, se debe a la interacción de factores ambientales y genéticos. El polimorfismo 677C>T del gen de la metilentetrahidrofolato reductasa (MTHFR) ha sido implicado como factor de riesgo para DTN. El objetivo de este trabajo fue investigar la asociación del polimorfismo 677C>T del gen de la MTHFR como factor de riesgo en los DTN. Se analizaron muestras de ADN de 52 madres con antecedente de al menos un hijo con DTN y de 119 madres controles. A través de la reacción en cadena de la polimerasa se amplificó un fragmento de 198 pb, el cual se sometió a digestión con la enzima HinfI. La frecuencia alélica de la MTHFR en los grupos problema y control fue de 51,92% y 34,45%; para el alelo T y 48,08% y 65,55%; para el C respectivamente. Se encontró diferencia significativa entre las frecuencias del alelo T y del alelo C (p: 0,002), así como entre las frecuencias genotípicas (p: 0,007) al ser comparadas en ambos grupos. El odds ratio (OR) para el genotipo TT vs CC se estimó como OR: 4,9 [IC 95%: 1,347-6,416] p: 0,002; CT+TT vs CC: OR: 2,9 [IC 95%: 1,347-6,416] p: 0,005; TT vs CT+CC: OR: 2,675 [IC 95%: 1,111-6,441] p: 0,024. Los presentes datos aportan una asociación significativa entre el polimorfismo 677C>T de la MTHFR y riesgo aumentado en las madres con antecedente de hijos con DTN.

Neural tube defects (NTD) are the most common congenital anomalies of the central nervous system, with a multifactorial pattern of inheritance, presumably involving the interaction of several genetic and environmental factors. The methylenetetrahydrofolate reductase (MTHFR) gene 677C>T polymorphism has been implicated as a risk factor for NTD. The main objective of this research was to investigate the association of the 677C>T polymorphism of the MTHFR gene as a genetic risk factor for NTD. Molecular analysis was performed in DNA samples from 52 mothers with antecedent of NTD offspring and from 119 healthy control mothers. Using the Polymerase Chain Reaction, a 198 bases pairs fragment was digested with the restriction enzyme HinfI. 677T MTHFR allele frequencies for the problem and the control groups were 51.92% and 34.45%, respectively, and 677C MTHFR allele frequencies were 48.08% and 65.55%, respectively. There were significant differences in allele (p: 0.002) and genotype (p: 0.007) frequencies between these two groups. The odds ratio (OR) to the TT genotype vs the CC genotype was estimated as OR: 4.9 [95% CI: 1,347-6.416] p: 0.002; CT+TT vs CC: OR: 2.9 [95% CI: 1.347-6.416] p: 0.005; TT vs CT+CC: OR: 2.675 [95% CI: 1,111-6.441] p: 0.024. The data presented in this study support the relationship between MTHFR 677C>T polymorphism and risk in mothers with antecedent of NTD offspring.

Comparison of homocysteinemia and MTHFR 677CT polymorphism with Framingham Coronary Heart Risk Score / Comparación de homocisteinemia y polimorfismo 677CT MTHFR con el Escore Framingham de Riesgo Coronario

Objective: The Framingham Coronary Heart Disease Risk Score is an important clinical tool. The aim of this cross-sectional study was to compare plasma homocysteine levels and polymorphism 677CT MTHFR with this score to determine the utility of these new biomarkers in clinical practice. Methods: Plasma homocysteine levels determined by chemiluminescence and polymorphism 677CT MTHFR, detected by PCR-RFLP, were compared with Framingham coronary risk score in a cross-sectional survey on 68 men and 165 women. Results: Coronary heart disease risk augmented with an increase in the quartile of plasma homocysteine. In the 2nd, 3rd and 4th quartile of plasma homocysteine, men showed significantly (P < 0.001) higher risk than women. For the highest quartile of plasma homocysteine, OR of high-risk (10-year risk ≥ 20%) compared with the lowest quartile was 17.45 (95% CI: 5.79-52.01). Frequencies of CT and TT genotype and T allele were not over-represented in the individuals with score ≥ 10%. The higher plasma homocysteine concentrations in individuals with score ≥ 10% with respect to those with low risk (P < 0.005 and P < 0.001) were not due to the presence of T allele. The T allele (CT + TT genotypes) of the MTHFR C677T polymorphism was not significantly associated with an increased risk of coronary disease (OR = 1.09, 95% CI = 0.50-2.39, P = 0.844). Conclusions: The present study demonstrated an association between plasma homocysteine levels and the severity of coronary heart disease estimated with the Framingham coronary risk score, and this association appeared to be independent on the genotype of MTHFR. We postulate that plasma homocysteine is effective enough, considered even in isolation.

Objetivo: La puntuación del riesgo coronario de Framingham es una importante herramienta clínica. El objetivo del presente estudio transversal fue comparar los niveles plasmáticos de homocisteína plasmática y el polimorfismo 677CT de la MTHFR con esta herramienta para determinar la utilidad de estos nuevos biomarcadores en la práctica clínica. Métodos: Los niveles de homocisteína plasmática determinados por quimioluminiscencia y el polimorfismo 677CT MTHFR por PCR-RFLP fueron comparados con la puntuación del riesgo coronario de Framingham en un estudio transversal sobre 68 hombres y 165 mujeres. Resultados: El riesgo de enfermedad coronaria aumentó con el incremento en los cuartiles de homocisteína plasmática. En el segundo, tercero y cuarto cuartil de homocisteína plasmática los hombres mostraron significativamente (p < 0.001) mayor riesgo que las mujeres. Para el cuartil más alto de homocisteína plasmática, la OR de riesgo alto (riesgo a 10 años ≥ 20%) comparado con el cuartil más bajo fue 17,45 (IC 95%: 5,79-52,01; p < 0.001). Las frecuencias de los genotipos CT y TT y del alelo T no estuvieron aumentados en los individuos con una puntuación ≥ 10%. Las mayores concentraciones de homocisteína plasmática en los individuos con una puntuación ≥ 10% respecto a los de bajo riesgo (p < 0.005 y p < 0.001) no se debieron a la presencia del alelo T. El alelo T (genotipos CT + TT) del polimorfismo MTHFR C677T no estuvo significativamente asociado con mayor riesgo de enfermedad coronaria (OR = 1.09, IC 95% = 0.50-2.39, p = 0.844). Conclusiones: El presente estudio mostró una asociación entre los niveles de homocisteína plasmática y la severidad de la enfermedad coronaria estimada con el algoritmo de puntuación de riesgo coronario de Framingham y esta asociación resultó ser independiente del genotipo de MTHFR. Postulamos que la homocisteína plasmática es lo suficientemente eficaz, estudiada incluso aisladamente.

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

OBJECTIVE: The Framingham Coronary Heart Disease Risk Score is an important clinical tool. The aim of this cross-sectional study was to compare plasma homocysteine levels and polymorphism 677CT MTHFR with this score to determine the utility of these new biomarkers in clinical practice. METHODS: Plasma homocysteine levels determined by chemiluminescence and polymorphism 677CT MTHFR, detected by PCR-RFLP, were compared with Framingham coronary risk score in a cross-sectional survey on 68 men and 165 women. RESULTS: Coronary heart disease risk augmented with an increase in the quartile of plasma homocysteine. In the 2nd, 3rd and 4th quartile of plasma homocysteine, men showed significantly (P<0.001) higher risk than women. For the highest quartile of plasma homocysteine, OR of high-risk (10-year risk≥20%) compared with the lowest quartile was 17.45 (95% CI: 5.79-52.01). Frequencies of CT and TT genotype and T allele were not over-represented in the individuals with score≥10%. The higher plasma homocysteine concentrations in individuals with score≥10% with respect to those with low risk (P<0.005 and P<0.001) were not due to the presence of T allele. The T allele (CT+TT genotypes) of the MTHFR C677T polymorphism was not significantly associated with an increased risk of coronary disease (OR=1.09, 95% CI=0.50-2.39, P=0.844). CONCLUSIONS: The present study demonstrated an association between plasma homocysteine levels and the severity of coronary heart disease estimated with the Framingham coronary risk score, and this association appeared to be independent on the genotype of MTHFR. We postulate that plasma homocysteine is effective enough, considered even in isolation.

Homocisteína, polimorfismos MTHFR C677T, A1298C y variables clínico-bioquímicas en población mexicana / Homocysteine, MTHFR C677T and A1298C polymorphisms, and clinical and biochemical variables in the mexican population / Homocisteína, polimorfismos MTHFR C677T, A1298C e variáveis clínico-bioquímicas em população mexicana

El objetivo del trabajo consistió en analizar la relación del nivel sérico de homocisteína (Hcy) con los polimorfismos de la metilentetrahidrofolato reductasa MTHFR C677T y A1298C y variables clínicas y bioquímicas en población mexicana. Se determinó el nivel de Hcy (inmunoensayo) y de polimorfismos (PCR/RFLP) en 102 individuos de la población general. El genotipo 677TT mostró asociación significativa con el peso corporal (r=0,012) y el genotipo 1298CC tuvo tendencia a asociarse con el IMC (r~0,06). Los valores séricos de Hcy en mujeres (51/102) fueron 8,33±1,86 µmol/L y en hombres (51/102) 11,64±4,15 µmol/L. La Hcy mostró asociación positiva con peso corporal (r=0,004) y asociación negativa con Hb y Hto (r=0,001). Se encontró mayor nivel de Hcy en individuos fumadores (r=0,009) y una tendencia hacia hiperhomocisteinemia en alcohólicos y en mujeres menopáusicas. No se evidenció asociación de Hcy con los polimorfismos MTHFR C677T y A1298C, sin embargo, el análisis con el modelo de herencia dominante para el polimorfismo C677T (TT+CT vs. CC) mostró un efecto semidominante (r<0,10). En este estudio, la presencia de los polimorfismos MTHFR C677T y A1298C no representó ser un factor de riesgo significativo para hiperhomocisteinemia, sin embargo, se encontraron diferencias que puntualizan la posible dependencia de los niveles de Hcy en relación con los genotipos modificados con diversos factores ambientales.

The objective of the current work was to analyze the relationship of serum homocysteine (Hcy) with MTHFR C677T and A1298C polymorphisms and clinical and biochemical variables in the Mexican population. Hcy (immunoassay) levels and polymorphism (PCR/RFLP) levels were determined in 102 individuals from the general population. The 677TT genotype showed significant association with body weight (r=0.012) and the 1298CC genotype tended to be associated with BMI (r~0.06). Serum levels of Hcy in women (51/102) were 8.33±1.86 µmol/L and in men (51/102) 11.64± 4.15 µmol/L. The Hcy was positively as-sociated with body weight (r=0.004) and negatively with Hb and Hct (r=0.001). Higher levels of Hcy were found in smokers (r=0.009) and a tendency to hyperhomocysteinemia in alcoholics and in menopausal women. There was no association of Hcy with MTHFR C677T and A1298C polymorphisms, although the analysis with dominant inheritance model for the C677T polymorphism (TT + CT vs. CC) showed a semi-dominant effect (r<0.10). In this study, the presence of MTHFR C677T and A1298C polymorphisms did not represent a significant risk factor for hyperhomocysteinemia; however, those differences may point out the dependence of the relative levels of Hcy modifed genotypes on various environmental factors.

O objetivo deste trabalho foi analisar a relação do nível sérico de homocisteína (Hcy) com os polimorfismos da metilenotetrahidrofolato redutase MTHFR C677T e A1298C e variáveis clínicas e bioquímicas na po-pulação mexicana. Foi determinado o nível de Hcy (imunoensaio) e de polimorfismos (PCR/RFLP) em 102 indivíduos da população geral. O genótipo 677TT mostrou associação significativa com o peso corporal (r =0,012) e o genótipo 1298CC teve tendência a se associar com o IMC (r~0,06). Os níveis séricos de Hcy em mulheres (51/102) foram 8,33±1,86 µmol/L e em homens (51/102) 11,64±4,15 µmol/L. A Hcy mos-trou associação positiva com o peso corporal (r=0,004) e associação negativa com Hb e Hto (r=0,001). Encontraram-se níveis mais elevados de Hcy em fumantes (p=0,009) e uma tendência para hiperhomo-cisteinemia em alcoólatras e em mulheres na menopausa. Nenhuma associação se mostrou entre Hcy e os polimorfismos MTHFR C677T e A1298C, no entanto, a análise com modelo de herança dominante para o polimorfismo C677T (TT+CT vs. CC) mostrou um efeito semidominantes (r<0,10). Neste estudo, a presença dos polimorfismos MTHFR C677T e A1298C não representou ser um fator de risco significativo para a hiper-homocisteinemia, no entanto, foram encontradas diferenças que apontam a possível dependência dos níveis de Hcy relativos aos genótipos modificados com diversos fatores ambientais.

Homocisteína, polimorfismos MTHFR C677T, A1298C y variables clínico-bioquímicas en población mexicana / Homocysteine, MTHFR C677T and A1298C polymorphisms, and clinical and biochemical variables in the mexican population / Homocisteína, polimorfismos MTHFR C677T, A1298C e variáveis clínico-bioquímicas em populaþÒo mexicana

El objetivo del trabajo consistió en analizar la relación del nivel sérico de homocisteína (Hcy) con los polimorfismos de la metilentetrahidrofolato reductasa MTHFR C677T y A1298C y variables clínicas y bioquímicas en población mexicana. Se determinó el nivel de Hcy (inmunoensayo) y de polimorfismos (PCR/RFLP) en 102 individuos de la población general. El genotipo 677TT mostró asociación significativa con el peso corporal (r=0,012) y el genotipo 1298CC tuvo tendencia a asociarse con el IMC (r~0,06). Los valores séricos de Hcy en mujeres (51/102) fueron 8,33±1,86 Amol/L y en hombres (51/102) 11,64±4,15 Amol/L. La Hcy mostró asociación positiva con peso corporal (r=0,004) y asociación negativa con Hb y Hto (r=0,001). Se encontró mayor nivel de Hcy en individuos fumadores (r=0,009) y una tendencia hacia hiperhomocisteinemia en alcohólicos y en mujeres menopáusicas. No se evidenció asociación de Hcy con los polimorfismos MTHFR C677T y A1298C, sin embargo, el análisis con el modelo de herencia dominante para el polimorfismo C677T (TT+CT vs. CC) mostró un efecto semidominante (r<0,10). En este estudio, la presencia de los polimorfismos MTHFR C677T y A1298C no representó ser un factor de riesgo significativo para hiperhomocisteinemia, sin embargo, se encontraron diferencias que puntualizan la posible dependencia de los niveles de Hcy en relación con los genotipos modificados con diversos factores ambientales.(AU)

The objective of the current work was to analyze the relationship of serum homocysteine (Hcy) with MTHFR C677T and A1298C polymorphisms and clinical and biochemical variables in the Mexican population. Hcy (immunoassay) levels and polymorphism (PCR/RFLP) levels were determined in 102 individuals from the general population. The 677TT genotype showed significant association with body weight (r=0.012) and the 1298CC genotype tended to be associated with BMI (r~0.06). Serum levels of Hcy in women (51/102) were 8.33±1.86 Amol/L and in men (51/102) 11.64± 4.15 Amol/L. The Hcy was positively as-sociated with body weight (r=0.004) and negatively with Hb and Hct (r=0.001). Higher levels of Hcy were found in smokers (r=0.009) and a tendency to hyperhomocysteinemia in alcoholics and in menopausal women. There was no association of Hcy with MTHFR C677T and A1298C polymorphisms, although the analysis with dominant inheritance model for the C677T polymorphism (TT + CT vs. CC) showed a semi-dominant effect (r<0.10). In this study, the presence of MTHFR C677T and A1298C polymorphisms did not represent a significant risk factor for hyperhomocysteinemia; however, those differences may point out the dependence of the relative levels of Hcy modifed genotypes on various environmental factors.(AU)

O objetivo deste trabalho foi analisar a relaþÒo do nível sérico de homocisteína (Hcy) com os polimorfismos da metilenotetrahidrofolato redutase MTHFR C677T e A1298C e variáveis clínicas e bioquímicas na po-pulaþÒo mexicana. Foi determinado o nível de Hcy (imunoensaio) e de polimorfismos (PCR/RFLP) em 102 indivíduos da populaþÒo geral. O genótipo 677TT mostrou associaþÒo significativa com o peso corporal (r =0,012) e o genótipo 1298CC teve tendÛncia a se associar com o IMC (r~0,06). Os níveis séricos de Hcy em mulheres (51/102) foram 8,33±1,86 Amol/L e em homens (51/102) 11,64±4,15 Amol/L. A Hcy mos-trou associaþÒo positiva com o peso corporal (r=0,004) e associaþÒo negativa com Hb e Hto (r=0,001). Encontraram-se níveis mais elevados de Hcy em fumantes (p=0,009) e uma tendÛncia para hiperhomo-cisteinemia em alcoólatras e em mulheres na menopausa. Nenhuma associaþÒo se mostrou entre Hcy e os polimorfismos MTHFR C677T e A1298C, no entanto, a análise com modelo de heranþa dominante para o polimorfismo C677T (TT+CT vs. CC) mostrou um efeito semidominantes (r<0,10). Neste estudo, a presenþa dos polimorfismos MTHFR C677T e A1298C nÒo representou ser um fator de risco significativo para a hiper-homocisteinemia, no entanto, foram encontradas diferenþas que apontam a possível dependÛncia dos níveis de Hcy relativos aos genótipos modificados com diversos fatores ambientais.(AU)