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)

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.

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.

The gene polymorphisms of MTHFR C677T and the susceptibility of chronic pulmonary heart disease / 天津医药

Objective To investigate the relationship between gene polymorphisms of homocysteine (Hcy), metabolic enzymes methylenetetrahydrofolate reductase MTHFR C677T and chronic pulmonary heart disease (CPHD). Methods The gene polymorphisms of MTHFR C677T were determined by the polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP)in CPHD patients (n=120) and healthy control (HC, n=120), and genotyping was carried on. The automatic biochemistry analyzer was used to detect the level of Hcy and other related biochemical indicators. Results There was significant difference in Hcy level between the CPHD group and HC group (P<0.05). The mutation frequencies of CC, CT and TT were 24.17%, 43.33%and 32.50%, 35.00%, 47.50%and 17.50%in the CPHD group and HC group. The mutation frequencies of allele C/T were 45.83%and 54.17%in HC group, and 58.75%and 41.25%in control group. There was significant difference in the overall frequency distribution between the three genotypes (χ2 =8.010, P<0.05). The frequency of T allele was significantly higher in CPHD group than that in control group (χ2=8.025,P<0.05). Conclusion The increased Hcy and its metabolic enzyme MTHFR C677T may be involved in the occurrence and development of CPHD.

Hyper-homocysteinemia Inducing Hyperuricemia: What are the Mechanisms?

Hyperuricemia is related to metabolic syndrome, and is defined as an over-production or under-excretion of uric acid (UA), with increased UA serum concentration. Among other causes, Hyper-homocysteinemia (H-Hcy) can be responsible for hyperuricemia. The mechanisms underlying the association between these two conditions are unclear, but increased UA serum levels can be a consequence of renovascular atherosclerosis, with reduced UA excretion. An alternative hypothesis is the over-production of UA from adenosine (originating from S-adenosyl-homocysteine). Genetic polymorphism (C677T) of methylenetetrahydrofolate reductase (MTHFR) may contribute. A possible mechanism is purines biosyinthesis originating from this gene variant. However, the results obtained from several studies and meta-analyses of the relationship between H-Hcy and hyperuricemia are ambivalent, and broader research is needed.

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.

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.

Detection and analysis of plasma homocysteine levels and its metabolism related indicators in patients with primary angle-closure glaucoma / 国际眼科杂志(Guoji Yanke Zazhi)

?AIM: To explore the relation of homocysteine ( Hcy ) and its metabolic related indicators with primary angle-closure glaucoma ( PACG) .?METHODS: In this study, a total of 150 PACG patients and 150 controls were enrolled. The patients with PACG were diagnosed by applanation tonometer, Humphrey perimetry ( HVF ) , optical coherence tomography ( OCT ) , gonioscope. The normal controls were recruited from physical examination center. Blood samples were collected and the plasma was used to determine homocysteine, vitamin B12 and folic acid. DNA was extracted to determine the methylenetetrahydrofolate reductase ( MTHFR ) C677TT genotype and gene polymorphism.?RESULTS:There was a statistically significant difference (t=2. 04,P=0. 04) in mean homocysteine levels between patients with PACG ( 16. 11 ± 1. 66μmol/L ) and controls (15. 74± 1. 52μmol/L). The level of vitamin B12 in PACG group was 248. 09 ± 119. 07pg/mL and the control group was 230. 21 ± 142. 93pg/mL. No statistically significant difference was found on the vitamin B12 level between the two groups ( t = 0. 84, P = 0. 40 ). The folic acid levels showed no statistically significant differences( t=1. 65,P=0.17) between the PACG group(12. 02±7. 81ng/mL) and the control group (13. 15 ± 6. 25ng/mL). The frequency distribution of the MTHFR C677T genotypes was found to be significantly associated (χ2 =6. 2,P<0. 05) with PCAG (CC 84. 7%, CT 4. 7%, TT 10. 7%) as compared to the controls (CC 94. 7%, CT 2. 0%, TT 3. 3%). The frequency distribution of TT genotypes of MTHFR C677T in the PACG group was significantly higher than that in the control group. Moreover, our findings showed significant difference (χ2=14. 2,P<0. 05) between the allele frequency of the C677T single nucleotide polymorphism within the MTHFR gene in POAG patients ( T 87. 0%, C 13. 0%) and the control group(T 95. 7%,C 4. 3%) .?CONCLUSION: These results show that the Hcy level and the TT genotypes of MTHFR C677T were higher in the PACG patients than in controls. Therefore, our data suggests that high Hcy level and the related indicators are associated with high PACG risk.

Potential Risk Factors Associated With Vascular Diseases in Patients Receiving Treatment for Hypertension

BACKGROUND: Currently, the hypertension (HTN) patients undergo appropriate medical treatment, and traditional risk factors are highly controlled. Therefore, potential risk factors of atherosclerotic vascular diseases (AVD) and venous thromboembolisms (VTE) in HTN should be reconsidered. We investigated thrombophilic genetic mutations and existing biomarkers for AVD or VTE in HTN patients receiving treatment. METHODS: A total of 183 patients were enrolled: AVD with HTN (group A, n=45), VTE with HTN (group B, n=62), and HTN patients without any vascular diseases (group C, n=76). The lipid profile, homocysteine (Hcy) levels, D-dimers, fibrinogen, antithrombin, lupus anticoagulant, and anti-cardiolipin antibody (aCL) were evaluated. Prothrombin G20210A, Factor V G1691A, and methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C were analyzed. RESULTS: All patients revealed wild type prothrombin G20210A and Factor V G1691A polymorphisms. The frequency of MTHFR polymorphisms was 677CT (n=84, 45.9%); 677TT (n=46, 25.1%); 1298AC (n=46, 25.1%); and 1298CC (n=2, 1.1%). The MTHFR 677TT genotype tended to increase the odds ratio (OR) to AVD events in HTN patients (OR 2.648, confidence interval 0.982-7.143, P=0.05). The group A demonstrated significantly higher Hcy levels (P=0.009), fibrinogen (P=0.004), and platelet counts (P=0.04) than group C. Group B had significantly higher levels of D-dimers (P=0.0001), platelet count (P=0.0002), and aCL (P=0.02) frequency than group C. CONCLUSIONS: The MTHFR 677TT genotype and Hcy level could be potential risk factors associated with development of AVD in HTN patients receiving treatment. D-dimer and aCL might be useful to estimate the occurrence of VTE in them.

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.

MTHFR C677T Polymorphism, Homocysteine and B-Vitamins Status in a Sample of Chinese and Malay Subjects in Universiti Putra Malaysia

Introduction: Methylenetetrahydrofolate reductase (MTHFR) C677T is involved in folate and homocysteine metabolism. Disruption in the activity of this enzyme will alter their levels in the body. Methodology: This study assessed MTHFR C677T polymorphism and its relationship with serum homocysteine and Bvitamins levels in a sample of Chinese and Malays subjects in UPM, Serdang. One hundred subjects were randomly selected from among the university population. Folate, vitamin B12, B6, and homocysteine levels were determined using MBA, ECLIA, and HPLC, respectively. PCR coupled with HinfI digestion was used for detection of MTHFR C677T polymorphism. Results: The frequency of T allele was higher in the Chinese subjects (0.40) compared to the Malay (0.14). Folate, vitamin B12 and B6 levels were highest in the wild genotype in both ethnic groups. Subjects with heterozygous and homozygous genotype showed the highest homocysteine levels. The serum folate and homocysteine were mainly affected by homozygous genotype. Conclusion: MTHFR C677T polymorphism plays an important role in influencing the folate and homocysteine metabolism.

Polimorfismo C677T del gen de la metiltetrahidrofolato reductasa como factor de riesgo en mujeres con aborto recurrente / C677T polymorphism of the methylentetrahydrofolate reductase gene as risk factor in women with recurrent abortion

La patogénesis de los abortos espontáneos recurrentes es multifactorial; probablemente se debe a la interacción de varios factores ambientales y genéticos. El polimorfismo C677T del gen de la metiltetrahidrofolato reductasa (MTHFR), ha sido implicado como factor de riesgo para aborto espontáneo recurrente (AR). El objetivo de este trabajo fue investigar la asociación del polimorfismo C677T de la MTHFR como factor de riesgo en AR idiopático. Se analizaron 80 muestras de ADN, correspondientes a 30 mujeres con AR y a 50 mujeres controles. A través de la reacción en cadena de la polimerasa (PCR) se amplificó un fragmento de 198 pares de base (pb), el cual se sometió a digestión con la enzima de restricción HinfI, que reconoce el sitio de restricción creado por la transición C>T en la posición 677. La frecuencia alélica de la MTHFR en el grupo de estudio y control fue 35% y 33% respectivamente; para el alelo T y 65% y 67% respectivamente, para el alelo C. No se encontró diferencia significativa entre el alelo T ni el C al ser comparados en ambos grupos. No se demostró un factor predisponente entre el polimorfismo C677T de la MTHFR y el AR en la muestra estudiada.

The pathogenesis of recurrent spontaneous abortion is multifactorial, presumably involving the interaction of several genetic and environmental factors. The methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism has been implicated as risk factor for recurrent spontaneous abortion (RA). The main objective of this research was to investigate the association between the C677T polymorphism of the MTHFR gene as a genetic risk factor for idiopathic RA. Molecular analysis was performed in 80 DNA samples from 30 patients with RA and among 50 healthy control subjects. Using the Polymerase Chain Reaction (PCR), a 198 bp (bases pairs) fragment, was digested with the restriction enzyme HinfI, which can recognize the C > T substitution responsible for the polymorphism. 677T MTHFR allele frequencies for group with RA and the control group were 35% and 33%, respectively and 677C MTHFR allele frequencies were 65% and 67%, respectively. There was no significant difference in allele frequency between these two groups. The data presented in this study fail to support the relationship between MTHFR C677T polymorphism and risk in women with RA.

A Case-control Study on the Relationship between Methylenetetrahydrofolate Reductase C677T, A1298C and G1793A Polymorphism and the Risk of Stomach Cancer

PURPOSE: The methylenetetrahydrofolate reductase (MTHFR) play a central role in converting folate to methyl donor for DNA methylation. Genetic variation in folate metabolism are believed to contribute to the risk of acute lymphoblastic leukemia, colon, esophageal and stomach cancer, as well as cardiovascular and cerebrovascular disease. Generally, low folate level is known that it is associated with gastrointestinal neoplasm. Three common single nucleotide polymorphisms (SNPs) resulting in amino-acid changes (C677T/Ala222Val, A1298C/Glu428Ala and G1793A/Arg594Glu) has been described in MTHFR. We studied the relation of MTHFR C677T, A1298C and G1793A polymorphisms derived from stomach cancers and a control group in Korean people. METHODS: We performed a case-control study to examine the relationship between MTHFR C677, A1298C and G1793A polymorphism and the risk of stomach cancer. 124 individuals with stomach cancer and 288 healthy persons were analyzed. Blood sampling of each groups were performed, PCR-RFLP analyzed, as a results, MTHFR polymorphism genotypes of 677C/C, 677C/T, 677T/T, 1298AA, 1298AC, 1298CC, 1793GG, 1793GA and 1793AA were obtained. RESULTS: The genotype frequency of MTHFR C677T polymorphisms were 23.4% (CC), 51.6% (CT), 25.0% (TT), 76.6% (CT+TT) in case patients and 39.2% (CC), 36.8% (CT), 24.0% (TT), 60.8% (CT+TT) in control groups. The genotype frequency of MTHFR A1298C polymorphisms were 38.7% (AA), 54.0% (AC), 7.3% (CC), 61.3% (AC+CC) in case patients and 55.6% (AA), 40.3% (AC), 4.2% (CC), 44.4% (AC+CC) in control groups. The genotype frequency of MTHFR G1793A polymorphisms were 82.3% (GG), 16.9% (GA), 0.8% (AA), 17.7% (GA+AA) in case patients and 85.8% (GG), 11.8% (GA), 2.4% (AA), 14.2% (GA+AA) in control groups. 677TT and 677CT genotype was associated with a significantly increased risk for gastric cancer (adjusted OR=2.15, 95% confidence interval 1.16~3.95 in TT, adjusted OR=2.49, 95% CI 1.47~4.20 in CT) than the 677CC genotype, and 1298CC and 1298 AC genotype also was associated with a significantly increased risk for stomach cancer (adjusted OR=2.87, 95% CI 1.10~|7.49 in CC, adjusted OR= 2.07, 95% CI 1.31~3.26 in AC). But 1793AA and 1793GA genotypes were not association with a significantly increased risk for stomach cancer (adjusted OR=0.29, 95% CI 0.03~|2.47 in AA, adjusted OR=1.55, 95% CI 0.84~2.86 in GA) CONCLUSION: MTHFR C677T and A1298C polymorphism may influence stomach cancer, but MTHFR G1793A polymorphism need careful interpretation and confirmation in larger studies.

Methylenetetrahydrofolate Reductase C677T and A1298C Polymorphisms in Colorectal Cancer

PURPOSE: Recently, the role of vitamins, folate in particular, has been emphasized in the maintenance of health. Folate deficiency is known to give rise to developmental delay, pre-mature vascular disease, neural tube defects, acute leukemia, atherosclerotic vascular disease, delivery defects, breast cancers and gastrointestinal neoplasia. Methylenetetrahydrofolate reductase (MTHFR) is an essential enzyme in folate metabolism, and influences DNA synthesis and DNA methylation. Generally, a low folate level is known to be associated with gastrointestinal neoplasms. Also, the amino- acid-changing and enzyme-activity-reducing nucleotide polymorphism (677C-->T/Ala222Val) has been described in the MTHFR polymorphism and it brings about low enzyme activity, which may reduce DNA methylation and uracil misincorporation into DNA. These processes may be critical for the oncogenic transformation of human cells. Two common single nucleotide polymorphisms (SNPs) resulting in amino-acid changes (677C T/Ala222Val and 1298A C/Glu428Ala) have been described in MTHFR. We investigated the relation between the MTHFR C677T and A1298C polymorphisms derived from colorectal cancers and from controls in the Korean population. METHODS: One hundred forty-eight (148) individuals with colorectal cancer and 288 healthy persons were analyzed. Blood sampling of each group was performed by using a PCR- RFLP analysis, and MTHFR polymorphism genotypes of 677C/C, 677C/T, 677T/T, 1298AA, 1298AC, and 1298CC were obtained. RESULTS: The genotype frequencies of MTHFR C677T polymorphisms were 25.0% (CC), 48.0% (CT), 27.0% (TT), and 75.0% (CT+TT), respectively, in case patients and 39.2% (CC), 36.8% (CT), 24.0% (TT), and 60.8% (CT+TT) in controls. The genotype frequencies of MTHFR A1298C polymorphisms were 56.1% (AA), 372% (AC), 6.8% (CC), and 43.9% (AC+CC), respectively, in case patients and 55.6% (AA), 40.3% (AC), 4.2% (CC), and 44.4% (AC+CC) in controls. The 677TT and the 677CT genotypes were associated with significantly increased risks for colorectal cancer (adjusted OR=1.77 and 95% CI=1.02~3.04 in TT; adjusted OR=2.07 and 95% CI=1.28~3.35 in CT) than was the 677CC, genotype but the the 1298CC and 1298 AC genotypes were not associated with significantly increased risks for colorectal cancer (adjusted OR=1.75 and 95% CI= 0.71~4.26 in CC; adjusted OR=0.95 and 95% CI=0.62~1.45 in AC). CONCLUSIONS: The MTHFR C677T polymorphism may be influenced by colorectal cancer, but the role of the MTHFR A1298C polymorphism needs careful interpretation and confirmation in larger studies.