959 resultados para folic acid antagonist
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Les anomalies du tube neural (ATN) sont des anomalies développementales où le tube neural reste ouvert (1-2/1000 naissances). Afin de prévenir cette maladie, une connaissance accrue des processus moléculaires est nécessaire. L’étiologie des ATN est complexe et implique des facteurs génétiques et environnementaux. La supplémentation en acide folique est reconnue pour diminuer les risques de développer une ATN de 50-70% et cette diminution varie en fonction du début de la supplémentation et de l’origine démographique. Les gènes impliqués dans les ATN sont largement inconnus. Les études génétiques sur les ATN chez l’humain se sont concentrées sur les gènes de la voie métabolique des folates du à leur rôle protecteur dans les ATN et les gènes candidats inférés des souris modèles. Ces derniers ont montré une forte association entre la voie non-canonique Wnt/polarité cellulaire planaire (PCP) et les ATN. Le gène Protein Tyrosine Kinase 7 est un membre de cette voie qui cause l’ATN sévère de la craniorachischisis chez les souris mutantes. Ptk7 interagit génétiquement avec Vangl2 (un autre gène de la voie PCP), où les doubles hétérozygotes montrent une spina bifida. Ces données font de PTK7 comme un excellent candidat pour les ATN chez l’humain. Nous avons re-séquencé la région codante et les jonctions intron-exon de ce gène dans une cohorte de 473 patients atteints de plusieurs types d’ATN. Nous avons identifié 6 mutations rares (fréquence allélique <1%) faux-sens présentes chez 1.1% de notre cohorte, dont 3 sont absentes dans les bases de données publiques. Une variante, p.Gly348Ser, a agi comme un allèle hypermorphique lorsqu'elle est surexprimée dans le modèle de poisson zèbre. Nos résultats impliquent la mutation de PTK7 comme un facteur de risque pour les ATN et supporte l'idée d'un rôle pathogène de la signalisation PCP dans ces malformations.
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Introduction: the 5, 10-methylenetetrahydrofolate reductase (MTHFR) is an essential enzyme in folate metabolism; their polymorphisms have been associated with heart disease risk increase, obstetric problems, neural tube defects in fetuses and cancer susceptibility. This gene has a single nucleotide polymorphism, a C-T change at nucleotide 677, which affects significantly its enzymatic activity. Objective: because of the biological importance of this enzyme and the Colombian population genetic heterogeneity characteristic, a study was performed to determine allele and genotype frequencies of MTHFR C677T polymorphism in healthy individuals, taking into account that in Colombia there are only studies that have involved case-control methodology. Methods: we analyzed this polymorphism trough the amplification of the DNA of a 206 students sample population. Additionally, Colombian overall frequencies were calculated, using data from healthy controls reported in other studies. Results: a Hardy-Weinberg disequilibri m was found in the sample tested. For the Colombian data, we found that the global population was in equilibrium. Conclusion: T allele population frequency seems to be under positive selection pressure, which is reflected in the population allele increase, despite its deleterious effect. A Spanish study reported similar results and identified folic acid supplementation on expectant mothers as a probably cause of this change.
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Se realizó un estudio genético – poblacional en dos grupos etarios de población colombiana con la finalidad de evaluar las diferencias genéticas relacionadas con el polimorfismo MTHFR 677CT en busca de eventos genéticos que soporten la persistencia de este polimorfismo en la especie humana debido que este ha sido asociado con múltiples enfermedades. De esta manera se genotipificaron los individuos, se analizaron los genotipos, frecuencias alélicas y se realizaron diferentes pruebas genéticas-poblacionales. Contrario a lo observado en poblaciones Colombianas revisadas se identificó la ausencia del Equilibrio Hardy-Weinberg en el grupo de los niños y estructuras poblacionales entre los adultos lo que sugiere diferentes historias demográficas y culturales entre estos dos grupos poblacionales al tiempo, lo que soporta la hipótesis de un evento de selección sobre el polimorfismo en nuestra población. De igual manera nuestros datos fueron analizados junto con estudios previos a nivel nacional y mundial lo cual sustenta que el posible evento selectivo es debido a que el aporte de ácido fólico se ha incrementado durante las últimas dos décadas como consecuencia de las campañas de fortificación de las harinas y suplementación a las embarazadas con ácido fólico, por lo tanto aquí se propone un modelo de selección que se ajusta a los datos encontrados en este trabajo se establece una relación entre los patrones nutricionales de la especie humana a través de la historia que explica las diferencias en frecuencias de este polimorfismo a nivel espacial y temporal.
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Hyperhomocysteinemia has been related to various diseases, including homocystinuria, neurodegenerative and hepatic diseases. In the present study we initially investigated the effect of chronic homocysteine administration on some parameters of oxidative stress, named total radical-trapping antioxidant potential, total antioxidant reactivity, catalase activity, chemiluminescence, thiobarbituric acid-reactive substances, and total thiol content in liver of rats. We also performed histological analysis, evaluating steatosis, inflammatory infiltration, fibrosis, and glycogen/glycoprotein content in liver tissue sections from hyperhomocysteinemic rats. Finally, we evaluated the activities of aminotransferases in liver and plasma of hyperhomocysteinemic rats. Wistar rats received daily subcutaneous injection of Hcy from their 6th to their 28th day of life. Twelve hours after the last injection the rats were sacrificed, liver and plasma were collected. Hyperhomocysteinemia decreased antioxidant defenses and total thiol content, and increased lipid peroxidation in liver of rats, characterizing a reliable oxidative stress. Histological analysis indicated the presence of inflammatory infiltrate, fibrosis and reduced content of glycogen/glycoprotein in liver tissue sections from hyperhomocysteinemic rats. Aminotransferases activities were not altered by homocysteine. Our data showed a consistent profile of liver injury elicited by homocysteine, which could contribute to explain, at least in part, the mechanisms involved in human liver diseases associated to hyperhomocysteinemia. (C) 2009 ISDN. Published by Elsevier Ltd. All rights reserved.
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Aims: The premise that intrauterine malnutrition plays an important role in the development of cardiovascular and renal diseases implies that these disorders can be programmed during fetal life. Here, we analyzed the hypothesis that supplementation with mixed antioxidant vitamins and essential mineral in early life could prevent later elevation of blood pressure and vascular and renal dysfunction associated with intrauterine malnutrition. Main methods: For this, female Wistar rats were randomly divided into three groups on day 1 of pregnancy: control fed standard chow ad libitum; restricted group fed 50% of the ad libitum intake and a restricted plus micronutrient cocktail group treated daily with a combination of micronutrient (selenium, folate, vitamin C and vitamin E) by oral gavage. Key findings: In adult offspring, renal function and glomerular number were impaired by intrauterine malnutrition. and the prenatal micronutrient treatment did not prevent it. However, increased blood pressure and reduced endothelium-dependent vasodilation were prevented by the micronutrient prenatal treatment. Intrauterine malnutrition also led to reduced NO production associated with increased superoxide generation, and these parameters were fully normalized by this prenatal treatment. Significance: Our current findings indicate that programming alterations during fetal life can be prevented by interventions during the prenatal period, and that disturbance in availability of both antioxidant vitamins and mineral may play a crucial role in determining the occurrence of long-term cardiovascular injury. (C) 2009 Elsevier Inc. All rights reserved.
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Folate is shown to react with singlet-excited state of riboflavin in a diffusion controlled reaction and with triplet-excited state of riboflavin in a somewhat slower reaction with (3)k(q) = 4.8 x 10(8) L mol(-1) s(-1) in aqueous phosphate buffer at pH 7.4, ionic strength of 0.2 mol L(-1), and 25 degrees C. Singlet quenching is assigned as photo-induced reductive electron transfer from ground state folate to singlet-excited riboflavin, while triplet quenching is assigned as one-electron transfer rather than hydrogen atom transfer from folate to triplet-excited riboflavin, as the reaction quantum yield, phi = 0.32, is hardly influenced by solvent change from water to deuterium oxide, phi = 0.37. Cyclic voltammetry showed an irreversible two-electron anodic process for folate, E = 1.14 V versus NHE at a scan-rate of 50 mV s(-1), which appears to be kinetically controlled by the heterogeneous electron transfer from the substrates to the electrode. Main products of folate photooxidation sensitized by riboflavin were pterin-6-carboxylic acid and p-aminobenzoyl-L-glutamic acid as shown by liquid chromatographic ion-trap mass spectrometry (LC-IT-MS).
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Os defeitos de fechamento de tubo neural constituem uma das malformações mais freqüentes na espécie humana, apresentando alta morbi-mortalidade. Sua etiologia é considerada multifatorial, estando envolvidos fatores genéticos e ambientais. Estes fatores estão relacionados principalmente com o metabolismo da homocisteína. Realizamos um estudo de caso-controle com o objetivo de estudar os fatores bioquímicos e genéticos relacionados ao DTN na nossa população. Em pares de afetados com DTN e suas mães e pares de pacientes normais e suas mães foram avaliados dosagem de folato, vitamina B12, homocisteína e polimorfismos da enzima metileno tetraidrofolato redutase (MTHFR), C677T e A1298C. A dosagem de folato nos casos foi 11,37 ng/mL(±6,72) e nos controles 5,64 ng/mL(±4,16) (p<0,001). O folato sérico das mães foi 7,27 ng/mL (±4,48) e 3,90 ng/mL (±1,77) nas mães controles (p<0,001). A média de dosagem de vitamina B12 foi de 641,88 pg/mL ((±262,21) nos casos e 743,27 pg/mL (±433,52) nos controles (p= 0,205). A média de dosagem de vitamina B12 nas mães dos casos foi 354,75 pg/mL (±142,06) e 465,25 pg/mL (±194,91) nas mães controles (p=0,004). O nível de homocisteína plasmático médio foi 6,89 μmol/L(±4,48) para os casos e 5,41 μmol/L (±2,55) para os controles (p=0,099). Nas mães dos casos a dosagem média de homocisteína foi 7,23 μmol/L (±2,64) e 7,00 μmol/L (±2,24) nas mães controles (p=0,666). Não houve diferença entre a freqüência dos genótipos C677T e A1298C da MTHFR nos casos e controles e suas mães. Para o polimorfismo C677T as freqüências dos alelo C e T foram respectivamente 0,6585 e 0,3414 nos pacientes com DTN; 0,6590 e 0,3410 nos controles; 0,6460 e 0,3540 nas mães dos casos e 0,6136 e 0,3860 nas mães controles. Para o polimorfismo A1298C as freqüências dos alelos A e C foram respectivamente 0,7436 e 0,2564 nos pacientes com DTN; 0,7610 e 0,2390 nos controles; 0,8055 e 0,1945 nas mães dos casos e 0,8065 e 0,1935 nas mães controles. Identificamos que indivíduos homozigotos 677TT apresentam um maior nível de homocisteína e este é inversamente relacionado com os níveis de vitamina B12. Estes achados sugerem que uma alteração metabólica relacionada ao metabolismo da homocisteína e principalmente devido à diminuição da vitamina B12 seja um fator de risco para DTN na nossa população.
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Gene therapy, which involves the transfer of nucleic acid into target cells in patients, has become one of the most important and widely explored strategies to treat a variety of diseases, such as cancer, infectious diseases and genetic disorders. Relative to viral vectors that have high immunogenicity, toxicity and oncogenicity, non-viral vectors have gained a lot of interest in recent years. This is largely due to their ability to mimic viral vector features including the capacity to overcome extra- and intra-cellular barriers and to enhance transfection efficiency. Polyethyleneimine (PEI) has been extensively investigated as a non-viral vector. This cationic polymer, which is able to compact nucleic acid through electrostatic interactions and to transport it across the negatively charged cell membranes, has been shown to effectively transfect nucleic acid into different cell lines. Moreover, entrapment of gold nanoparticles (Au NPs) into such an amine-terminated polymer template has been shown to significantly enhance gene transfection efficiency. In this work, a novel non-viral nucleic acid vector system for enhanced and targeted nucleic acid delivery applications was developed. The system was based on the functionalization of PEI with folic acid (FA; for targeted delivery to cancer cells overexpressing FA receptors on their surface) using polyethylene glycol (PEG) as a linker molecule. This was followed by the preparation of PEI-entrapped Au NPs (Au PENPs; for enhancement of transfection efficiency). In the synthesis process, the primary amines of PEI were first partially modified with fluorescein isothiocyanate (FI) using a molar ratio of 1:7. The formed PEI-FI conjugate was then further modified with either PEG or PEGylated FA using a molar ratio of 1:1. This process was finally followed by entrapment of Au NPs into the modified polymers. The resulting conjugates and Au PENPs were characterized by several techniques, namely Nuclear Magnetic Resonance, Dynamic Light Scattering and Ultraviolet-Visible Spectroscopy, to assess their physicochemical properties. In the cell biology studies, the synthesized conjugates and their respective Au PENPs were shown to be non-toxic towards A2780 human ovarian carcinoma cells. The role of these materials as gene delivery agents was lastly evaluated. In the gene delivery studies, the A2780 cells were successfully transfected with plasmid DNA using the different vector systems. However, FA-modification and Au NPs entrapment were not determinant factors for improved transfection efficiency. In the gene silencing studies, on the other hand, the Au PENPs were shown to effectively deliver small interfering RNA, thereby reducing the expression of the B-cell lymphoma 2 protein. Based on these results, we can say that the systems synthesized in this work show potential for enhanced and targeted gene therapy applications.
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The imprecision of the frontier that separates those cognitive deficits inherent to the human physiological aging process from those which represent the early signs of nervous system degenerative pathologies ,very prevalent among the elderly, has brought attention to the need of studies aiming to establish clinical and/or laboratorial criteria to allow this differentiation. Elderly people living in poor and developing countries are frequently exposed to precarious socioeconomic conditions which facilitate the development of an array of pathologies which have metabolic and nutritional dysfunctions as the established or proposed etiological agents. The levels of certain micronutrients, such as the vitamins B12 and B9 (folic acid), and of some intermediary metabolites, such as homocysteine are being thought of as etiological factors and/or as biological markers of a group of alterations which affect the normal functioning of the nervous system with important reflexes upon cognitive performance. This study aims to investigate the influence of homocysteine, B12 vitamin and folic acid levels on the cognitive performance of the low income elderly population. This transversal study took place in Natal, Rio Grande do Norte State, Brazil, and involved 205 dwelling elderly people, users of the Programa de Saúde da Família, a public healthcare program, maintained by the city s health authorities. A multidimensional questionnaire was used to assess the socio-demographic aspects and the overall health and nutrition conditions. The cognitive performance was measured by the use of the Portuguese version of the Mini Mental State Exam (MMSE). The serum levels of homocysteine, B12 vitamin and folic acid were determined by chemiluminescence. The association between the socio-demographic and serum levels of Hcy, B12 vitamin and folic acid was determined by multiple linear regression. Serum levels higher than 13.5 μmol/l, indicative of hyperhomocysteinemia (HHcy), were found on 25.4% of the sample, being more prevalent in men (p<0.05). Deficitary levels of folic acid (<5ng/mol) and of B12 vitamin (<193 pg/ml) were found on 3.9% and 10.2% of the sample respectively. A negative correlation was found between cognitive performance with both age and HHcy and a positive correlation was found between cognitive performance and schooling. The isolated HHcy R2 values were an explanation to only 4% of the variance of the MMSE scores. However, when associated with schooling and age, this model explains about 25% of this association
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The congenital facial clefts are characterized by incomplete formation of the structures that separate the oral and nasal cavity. It is known that several environmental and genetic factors are involved in its development, among these, polymorphisms associated with folic acid metabolism have been investigated. In this sense, the objective was to observe the frequency of polymorphisms C677T and A1298C methylenetetrahydrofolate reductase gene (MTHFR), methionine synthase A2756G of (MTR), A66G of methionine synthase reductase (MTRR) A80G and the reduced folate carrier (RFC1) in patients with non-syndromic oral clefts, trying to match them with their development. Methods: We studied 140 patients with non-syndromic oral clefts and their mothers and 175 control subjects with their mothers, who underwent a questionnaire to obtain family information. Were collecting blood for DNA extraction from patients and their mothers to identify the genotypes of both by PCRRFLP, in addition to carrying out the determination of glucose, AST, ALT and serum creatinine, folic acid and vitamin B12 Serum and plasma homocysteine, and the hemogram. Results: Most patients have cleft lip and palate (55.8%), followed by isolated cleft palate (24.2%) and cleft lip (20%). Regarding gender, 62% of patients were male and 48% female and, after subdivision of the type of screwdriver according to sex was found a prevalence of males in the cracks of the type lip and palate (69 %) and lip (69.2%) and in the case of cleft palate was a female predominance (59%). The average concentration of serum folate in the group of mothers of cleft patients was significantly lower (13.8 ± 2.4 ng / mL) compared with the group of mothers of control subjects (18.8 ± 3.4 ng / mL) This was also observed for the group of cleft children as compared to controls, the dosage of folic acid had a significant difference with values of 15.6 ± 0.6 (ng / mL) and 17.9 ± 0.6 (ng / mL), respectively. For the biochemical measurements of glucose, AST, ALT and creatinine were not statistically different, nor was observed for haematological parameters performed. In assessing the frequency of polymorphisms C677T and A1298C MTHFR, A2756G MTR, MTRR A66G and A80G of the RFC1 there was no statistically significant difference in genotype distribution between cases and controls both for mothers and in the cleft. Conclusion: Although not observed association of polymorphisms with the development of cracks, the decrease in serum folate in the group of cleft patients and their mothers may reflect a disturbance in the metabolism of this metabolite, necessitating further studies such as studies methylation and expression to further elucidate the involvement of folate in the development of oral clefts
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The development of more selective and sensitive analytical methods is of great importance in different areas of knowledge, covering, for example, food, biotechnological, environmental and pharmaceutical sectors. The study aimed to employ the technique electroanalytical differential pulse voltammetry (DPV) as an innovative and promising alternative for identification and quantification of organic compounds. The organic compounds were investigated in this study oxalic acid (OA) and folic acid (FA). The electrochemical oxidation of oxalic acid has been extensively studied as a model reaction in the boundary between the organic and inorganic electrochemistry. Since the AF, an essential vitamin for cell multiplication in all tissues, which is essential for DNA synthesis. The AF has been investigated using analytical techniques, liquid chromatography and molecular absorption spectrophotometry. The results obtained during the experimental procedure indicated that the process of electrochemical oxidation of oxalic acid is strongly dependent on the nature of the anode material and the oxidation mechanism, which affects their detection. Efficient removal was observed in Ti/PbO2 anodes, graphite, BDD and Pt 90, 85, 80 and 78% respectively. It was also shown that the DPV employing glassy carbon electrode offers a fast, simple, reliable and economical way to determine the AO during the process of electrochemical oxidation. Furthermore, electroanalytical methods are more expensive than commonly used chromatographic analysis and other instrumental methods involving toxic reagents and higher cost. Compared with the classical method of titration and DPV could be a good fit, confidence intervals and detection limits confirming the applicability of electroanalytical technique for monitoring the degradation of oxalic acid. For the study of AF was investigated the electrocatalytic activity of the carbon paste electrode for identification and quantification in pharmaceutical formulations by applying the DPV. The results obtained during the experimental procedure showed an irreversible oxidation peak at 9.1 V characteristic of FA. The carbon paste sensor showed low detection limit of 5.683×10−8 mol L-1 reducing matrix effects. The spectrophotometric analysis showed lower concentrations of HF compared with those obtained by HPLC and DPV. The levels of AF were obtained according to the methodology proposed by the Brazilian Pharmacopoeia. The electroanalytical method (DPV) proposed is cheaper than GC analysis commonly used by the pharmaceutical industry. The results demonstrated the potential of these electroanalytical techniques for future applications in environmental, chemical and biological sensors
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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INTRODUÇÃO: AIDS é uma doença causada pelo HIV que compromete o sistema imune do organismo. O advento da terapia antirretroviral (TARV) altamente eficaz promoveu melhora substancial do prognóstico da doença e da qualidade de vida dos pacientes com HIV/AIDS. Durante seu tratamento prolongado, notam-se algumas alterações hematológicas, dentre elas, anemia e macrocitose, bem como carências de micronutrientes, tais como, de vitamina B12 e ácido fólico. O objetivo do presente trabalho é relacionar a macrocitose e anemia ao uso de TARV, ou à deficiência de vitamina B12 ou de ácido fólico. MÉTODOS: Foram avaliados 110 pacientes HIV positivos, comparando-se aqueles em uso de TARV com zidovudina (AZT) (grupo 1), TARV sem AZT (grupo 2) ou sem uso de TARV (grupo 3). RESULTADOS: Os pacientes dos três grupos não apresentaram diferenças estatísticas significativas quanto aos níveis de hemoglobina (p = 0,584) e de ácido fólico (p = 0,956). Os pacientes do grupo 1 (G1) apresentaram volume corpuscular médio (VCM) aumentado quando comparado ao grupo 3 (G3) (p < 0,05), bem como do grupo 2 (G2) em relação ao G3 (p < 0,001). As dosagens de vitamina B12 do G1 e G3 foram menores do que as encontradas pelo G2 (p = 0,008). CONCLUSÕES: Conclui-se que os indivíduos em uso de TARV apresentaram macrocitose, embora não pudesse ser relacionada ao tipo de TARV ou a deficiência de vitamina B12. Entretanto, a deficiência de ácido fólico não esteve relacionada ao uso de TARV e nem à macrocitose.
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A homocisteína está envolvida na gênese da aterosclerose e, assim, é considerada um importante e prevalente fator de risco na doença arterial periférica. O estado nutricional vitamínico deficiente, em especial do folato, é a principal causa de hiper-homocisteinemia nesses casos. Embora ainda não haja consenso sobre a dose exata e a forma de utilização do folato em suplementos e sobre adequação alimentar ou fortificação de cereais para o tratamento da hiper-homocisteinemia, diversos estudos realizados em pacientes com doença vascular periférica mostraram que o folato, isoladamente, pode reduzir as concentrações de homocisteína, bem como a concentração de alguns marcadores biológicos do processo de aterosclerose. No entanto, estudos recentes não comprovaram esse benefício sobre o processo inflamatório associado à hiper-homocisteinemia. Desta forma, embora a utilização isolada do folato seja uma terapêutica custo-efetiva no controle da hiper-homocisteinemia, seu impacto na evolução das doenças arteriais ainda persiste inconclusivo. Esta revisão abordará os efeitos obtidos com as diversas formas de utilização do folato no tratamento da hiper-homocisteinemia.
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Background: Oral clefts are one of the most common birth defects with significant medical, psychosocial, and economic ramifications. Oral clefts have a complex etiology with genetic and environmental risk factors. There are suggestive results for decreased risks of cleft occurrence and recurrence with folic acid supplements taken at preconception and during pregnancy with a stronger evidence for higher than lower doses in preventing recurrence. Yet previous studies have suffered from considerable design limitations particularly non-randomization into treatment. There is also well-documented effectiveness for folic acid in preventing neural tube defect occurrence at 0.4 mg and recurrence with 4 mg. Given the substantial burden of clefting on the individual and the family and the supportive data for the effectiveness of folic acid supplementation as well as its low cost, a randomized clinical trial of the effectiveness of high versus low dose folic acid for prevention of cleft recurrence is warranted.Methods/design: This study will assess the effect of 4 mg and 0.4 mg doses of folic acid, taken on a daily basis during preconception and up to 3 months of pregnancy by women who are at risk of having a child with nonsyndromic cleft lip with/without palate (NSCL/P), on the recurrence of NSCL/P. The total sample will include about 6,000 women (that either have NSCL/P or that have at least one child with NSCL/P) randomly assigned to the 4 mg and the 0.4 mg folic acid study groups. The study will also compare the recurrence rates of NSCL/P in the total sample of subjects, as well as the two study groups (4mg, 0.4 mg) to that of a historical control group. The study has been approved by IRBs (ethics committees) of all involved sites. Results will be disseminated through publications and presentations at scientific meetings.Discussion: The costs related to oral clefts are high, including long term psychological and socio-economic effects. This study provides an opportunity for huge savings in not only money but the overall quality of life. This may help establish more specific clinical guidelines for oral cleft prevention so that the intervention can be better tailored for at-risk women.