Sensitivity of human laryngeal squamous cell carcinoma Hep-2 to metrotexate chemoterapy

Aim: Methotrexate (MTX) is an antifolate agent that acts inhibiting purine and pyrimidine synthesis. The objective of the study was to evaluate the viability of Hep-2 human laryngeal cancer cells to the treatment with MTX chemotherapy in vitro. Methods: Cultured Hep-2 cells were treated with 0.25, 25.0 and 75 μM MTX for 24 h, and their viability was evaluated with Bcl-2-FITC antibody in flow cytometry. Results: The numbers of viable Hep-2 cells after 24 h treatment with 0.25, 25.0 and 75.0 uM MTX were 85.43%, 22.46% and 8.42%, respectively (p < 0.05). Therefore, MTX possesses a dose-dependent effect on viability of Hep-2 cells in vitro. Conclusion: The highest MTX concentration is associated with highest tumor cell sensitivity of human laryngeal cancer cells of Hep-2 line

19-base Pair Deletion Polymorphism Of The Dihydrofolate Reductase (dhfr) Gene: Maternal Risk Of Down Syndrome And Folate Metabolism [polimorfismo De Deleção De 19 Pares De Bases Do Gene Dihidrofolato Redutase (dhfr): Risco Materno Para Síndrome De Down E Metabolismo Do Folato]

Context and objective: Polymorphisms in genes involved in folate metabolism may modulate the maternal risk of Down syndrome (DS). This study evaluated the influence of a 19-base pair (bp) deletion polymorphism in intron-1 of the dihydrofolate reductase (DHFR) gene on the maternal risk of DS, and investigated the association between this polymorphism and variations in the concentrations of serum folate and plasma homocysteine (Hcy) and plasma methylmalonic acid (MMA). Design and setting: Analytical cross-sectional study carried out at Faculdade de Medicina de São José do Rio Preto (Famerp). Methods: 105 mothers of individuals with free trisomy of chromosome 21, and 184 control mothers were evaluated. Molecular analysis on the polymorphism was performed using the polymerase chain reaction (PCR) through differences in the sizes of fragments. Folate was quantified by means of chemiluminescence, and Hcy and MMA by means of liquid chromatography and sequential mass spectrometry. Results: There was no difference between the groups in relation to allele and genotype frequencies (P = 0.44; P = 0.69, respectively). The folate, Hcy and MMA concentrations did not differ significantly between the groups, in relation to genotypes (P > 0.05). Conclusions: The 19-bp deletion polymorphism of DHFR gene was not a maternal risk factor for DS and was not related to variations in the concentrations of serum folate and plasma Hcy and MMA in the study population.1284215218Freeman, S.B., Allen, E.G., Oxford-Wright, C.L., The National Down Syndrome Project: Design and implementation (2007) Public Health Rep, 122 (1), pp. 62-72Ramírez, N.J., Belalcázar, H.M., Yunis, J.J., Parental origin, nondisjunction, and recombination of the extra chromosome 21 in Down syndrome: A study in a sample of the Colombian population (2007) Biomedica, 27 (1), pp. 141-148James, S.J., Pogribna, M., Pogribny, I.P., Abnormal folate metabolism and mutation in the methylenetetrahydrofolate reductase gene may be maternal risk factors for Down syndrome (1999) Am J Clin Nutr, 70 (4), pp. 495-501Patterson, D., Folate metabolism and the risk of Down syndrome (2008) Downs Syndr Res Pract, 12 (2), pp. 93-97Biselli, J.M., Goloni-Bertollo, E.M., Zampieri, B.L., Genetic polymorphisms involved in folate metabolism and elevated plasma concentrations of homocysteine: Maternal risk factors for Down syndrome in Brazil (2008) Genet Mol Res, 7 (1), pp. 33-42Meguid, N.A., Dardir, A.A., Khass, M., MTHFR genetic polymorphism as a risk factor in Egyptian mothers with Down syndrome children (2008) Dis Markers, 24 (1), pp. 19-26Coppedè, F., Migheli, F., Bargagna, S., Association of maternal polymorphisms in folate metabolizing genes with chromosome damage and risk of Down syndrome offspring (2009) Neurosci Lett, 449 (1), pp. 15-19Pozzi, E., Vergani, P., Dalprà, L., Maternal polymorphisms for methyltetrahydrofolate reductase and methionine synthetase reductase and risk of children with Down syndrome (2009) Am J Obstet Gynecol, 200 (6), pp. 636e1-636e6Stanislawska-Sachadyn, A., Brown, K.S., Mitchell, L.E., An insertion/deletion polymorphism of the dihydrofolate reductase (DHFR) gene is associated with serum and red blood cell folate concentrations in women (2008) Hum Genet, 123 (3), pp. 289-295Johnson, W.G., Stenroos, E.S., Spychala, J.R., New 19 bp deletion polymorphism in intron-1 of dihydrofolate reductase (DHFR): A risk factor for spina bifida acting in mothers during pregnancy? (2004) Am J Med Genet A, 124 A (4), pp. 339-345Parle-McDermott, A., Pangilinan, F., Mills, J.L., The 19-bp deletion polymorphism in intron-1 of dihydrofolate reductase (DHFR) may decrease rather than increase risk for spina bifida in the Irish population (2007) Am J Med Genet A, 143 A (11), pp. 1174-1180Xu, X., Gammon, M.D., Wetmur, J.G., A functional 19-base pair deletion polymorphism of dihydrofolate reductase (DHFR) and risk of breast cancer in multivitamin users (2007) Am J Clin Nutr, 85 (4), pp. 1098-1102Gellekink, H., Blom, H.J., van der Linden, I.J., den Heijer, M., Molecular genetic analysis of the human dihydrofolate reductase gene: Relation with plasma total homocysteine, serum and red blood cell folate levels (2007) Eur J Hum Genet, 15 (1), pp. 103-109Miller, S.A., Dykes, D.D., Polesky, H.F., A simple salting out procedure for extracting DNA from human nucleated cells (1988) Nucleic Acids Res, 16 (3), p. 1215Dulucq, S., St-Onge, G., Gagné, V., DNA variants in the dihydrofolate reductase gene and outcome in childhood ALL (2008) Blood, 111 (7), pp. 3692-3700Haddad, R., Mendes, M.A., Höehr, N.F., Eberlin, M.N., Amino acid quantitation in aqueous matrices via trap and release membrane introduction mass spectrometry: Homocysteine in human plasma (2001) Analyst, 126 (8), pp. 1212-1215de Andrade, C.R., Fukada, S.Y., Olivon, V.C., Alpha1D-adrenoceptor-induced relaxation on rat carotid artery is impaired during the endothelial dysfunction evoked in the early stages of hyperhomocysteinemia (2006) Eur J Pharmacol, 543 (1-3), pp. 83-91Carvalho, V.M., Kok, F., Determination of serum methylmalonic acid by alkylative extraction and liquid chromatography coupled to tandem mass spectrometry (2008) Anal Biochem, 381 (1), pp. 67-73Fenech, M., The role of folic acid and Vitamin B12 in genomic stability of human cells (2001) Mutat Res, 475 (1-2), pp. 57-67Wang, X., Thomas, P., Xue, J., Fenech, M., Folate deficiency induces aneuploidy in human lymphocytes in vitro-evidence using cytokinesis-blocked cells and probes specific for chromosomes 17 and 21 (2004) Mutat Res, 551 (1-2), pp. 167-180Beetstra, S., Thomas, P., Salisbury, C., Turner, J., Fenech, M., Folic acid deficiency increases chromosomal instability, chromosome 21 aneuploidy and sensitivity to radiation-induced micronuclei (2005) Mutat Res, 578 (1-2), pp. 317-326Finkelstein, J.D., Martin, J.J., Homocysteine (2000) Int J Biochem Cell Biol, 32 (4), pp. 385-389Coppedè, F., Marini, G., Bargagna, S., Folate gene polymorphisms and the risk of Down syndrome pregnancies in young Italian women (2006) Am J Med Genet A, 140 (10), pp. 1083-1091Wang, S.S., Qiao, F.Y., Feng, L., Lv, J.J., Polymorphisms in genes involved in folate metabolism as maternal risk factors for Down syndrome in China (2008) J Zhejiang Univ Sci B, 9 (2), pp. 93-99Kalmbach, R.D., Choumenkovitch, S.F., Troen, A.P., A 19-base pair deletion polymorphism in dihydrofolate reductase is associated with increased unmetabolized folic acid in plasma and decreased red blood cell folate (2008) J Nutr, 138 (12), pp. 2323-2327van der Linden, I.J., Nguyen, U., Heil, S.G., Variation and expression of dihydrofolate reductase (DHFR) in relation to spina bifida (2007) Mol Genet Metab, 91 (1), pp. 98-103Barkai, G., Arbuzova, S., Berkenstadt, M., Heifetz, S., Cuckle, H., Frequency of Down's syndrome and neural tube defects in the same family (2003) Lancet, 361 (9366), pp. 1331-1335Guéant, J.L., Guéant-Rodriguez, R.M., Anello, G., Genetic determinants of folate and vitamin B12 metabolism: A common pathway in neural tube defect and Down syndrome? (2003) Clin Chem Lab Med, 41 (11), pp. 1473-1477Klee, G.G., Cobalamin and folate evaluation: Measurement of methylmalonic acid and homocysteine vs vitamin B(12) and folate (2000) Clin Chem, 46 (8 PART 2), pp. 1277-1283Galloway, M., Rushworth, L., Red cell or serum folate? Results from the National Pathology Alliance benchmarking review (2003) J Clin Pathol, 56 (12), pp. 924-926Bunduki, V., Dommergues, M., Zittoun, J., Maternal-fetal folate status and neural tube defects: A case control study (1995) Biol Neonate, 67 (3), pp. 154-159Kilbride, J., Baker, T.G., Parapia, L.A., Khoury, S.A., Iron status, serum folate and B(12) values in pregnancy and postpartum: Report from a study in Jordan (2000) Ann Saudi Med, 20 (5-6), pp. 371-376Zhang, T., Xin, R., Gu, X., Maternal serum vitamin B12, folate and homocysteine and the risk of neural tube defects in the offspring in a high-risk area of China (2009) Public Health Nutr, 12 (5), pp. 680-686Eser, B., Cosar, M., Eser, O., 677C>T and 1298A>C polymorphisms of methylenetetrahydropholate reductase gene and biochemical parameters in Turkish population with spina bifida occulta (2010) Turk Neurosurg, 20 (1), pp. 9-1

The MTR A2756G polymorphism is associated with an increase of plasma homocysteine concentration in Brazilian individuals with Down syndrome

Individuals with Down syndrome (DS) present decreased homocysteine (Hcy) concentration, reflecting a functional folate deficiency secondary to overexpression of the cystathionine ß-synthase gene. Since plasma Hcy may be influenced by genetic polymorphisms, we evaluated the influence of C677T and A1298C polymorphisms in the methylenetetrahydrofolate reductase gene (MTHFR), of A2756G polymorphism in the methionine synthase gene (MTR), and of A80G polymorphism in the reduced folate carrier 1 gene on Hcy concentrations in Brazilian DS patients. Fifty-six individuals with free trisomy 21 were included in the study. Plasma Hcy concentrations were measured by liquid chromatography_tandem mass spectrometry with linear regression coefficient r² = 0.9996, average recovery between 92.3 to 108.3% and quantification limits of 1.0 µmol/L. Hcy concentrations >15 µmol/L were considered to characterize hyperhomocystinemia. Genotyping for the polymorphisms was carried out by polymerase chain reaction followed by enzyme digestion and allele-specific polymerase chain reaction. The mean Hcy concentration was 5.2 ± 3.3 µmol/L. There was no correlation between Hcy concentrations and age, gender or MTHFR C677T, A1298C and reduced folate carrier 1 A80G genotype. However, Hcy concentrations were significantly increased in the MTR 2756AG heterozygous genotype compared to the MTR 2756AA wild-type genotype. The present results suggest that the heterozygous genotype MTR 2756AG is associated with the increase in plasma Hcy concentrations in this group of Brazilian patients with DS.344

Genetic variability of vascular endothelial growth factor and prognosis of head and neck cancer in a Brazilian population

Vascular endothelial growth factor (VEGF) is one of the most potent endothelial cell mitogens and plays a critical role in angiogenesis. Polymorphisms in this gene have been evaluated in patients with several types of cancer. The objectives of this study were to determine if there was an association of the -1154G/A polymorphism of the VEGF gene with head and neck cancer and the interaction of this polymorphism with lifestyle and demographic factors. Additionally, the distribution of the VEGF genotype was investigated with respect to the clinicopathological features of head and neck cancer patients. The study included 100 patients with histopathological diagnosis of head and neck squamous cell carcinoma. Patients with treated tumors were excluded. A total of 176 individuals 40 years or older were included in the control group and individuals with a family history of neoplasias were excluded. Analysis was performed after extraction of genomic DNA using the real-time PCR technique. No statistically significant differences between allelic and genotype frequencies of -1154G/A VEGF polymorphism were identified between healthy individuals and patients. The real-time PCR analyses showed a G allele frequency of 0.72 and 0.74 for patients and the control group, respectively. The A allele showed a frequency of 0.28 for head and neck cancer patients and 0.26 for the control group. However, analysis of the clinicopathological features showed a decreased frequency of the A allele polymorphism in patients with advanced (T3 and T4) tumors (OR = 0.36; 95%CI = 0.14-0.93; P = 0.0345). The -1154A allele of the VEGF gene may decrease the risk of tumor growth and be a possible biomarker for head and neck cancer. This polymorphism is associated with increased VEGF production and may have a prognostic importance

5-Methyltetrahydrofolate-homocysteine methyltransferase gene polymorphism (MTR) and risk of head and neck cancer

The functional effect of the A>G transition at position 2756 on the MTR gene (5-methyltetrahydrofolate-homocysteine methyltransferase), involved in folate metabolism, may be a risk factor for head and neck squamous cell carcinoma (HNSCC). The frequency of MTR A2756G (rs1805087) polymorphism was compared between HNSCC patients and individuals without history of neoplasias. The association of this polymorphism with clinical histopathological parameters was evaluated. A total of 705 individuals were included in the study. The polymerase chain reaction-restriction fragment length polymorphism technique was used to genotype the polymorphism. For statistical analysis, the chi-square test (univariate analysis) was used for comparisons between groups and multiple logistic regression (multivariate analysis) was used for interactions between the polymorphism and risk factors and clinical histopathological parameters. Using univariate analysis, the results did not show significant differences in allelic or genotypic distributions. Multivariable analysis showed that tobacco and alcohol consumption (P < 0.05), AG genotype (P = 0.019) and G allele (P = 0.028) may be predictors of the disease and a higher frequency of the G polymorphic allele was detected in men with HNSCC compared to male controls (P = 0.008). The analysis of polymorphism regarding clinical histopathological parameters did not show any association with the primary site, aggressiveness, lymph node involvement or extension of the tumor. In conclusion, our data provide evidence that supports an association between the polymorphism and the risk of HNSCC

Genetic Polymorphisms Modulate The Folate Metabolism Of Brazilian Individuals With Down Syndrome

Individuals with Down syndrome (DS) carry three copies of the Cystathionine β-synthase (CβS) gene. The increase in the dosage of this gene results in an altered profile of metabolites involved in the folate pathway, including reduced homocysteine (Hcy), methionine, S-adenosylhomocysteine (SAH) and S-adenosylmethionine (SAM). Furthermore, previous studies in individuals with DS have shown that genetic variants in genes involved in the folate pathway influence the concentrations of this metabolism's products. The purpose of this study is to investigate whether polymorphisms in genes involved in folate metabolism affect the plasma concentrations of Hcy and methylmalonic acid (MMA) along with the concentration of serum folate in individuals with DS. Twelve genetic polymorphisms were investigated in 90 individuals with DS (median age 1.29 years, range 0.07-30.35 years; 49 male and 41 female). Genotyping for the polymorphisms was performed either by polymerase chain reaction (PCR) based techniques or by direct sequencing. Plasma concentrations of Hcy and MMA were measured by liquid chromatography-tandem mass spectrometry as previously described, and serum folate was quantified using a competitive immunoassay. Our results indicate that the MTHFR C677T, MTR A2756G, TC2 C776G and BHMT G742A polymorphisms along with MMA concentration are predictors of Hcy concentration. They also show that age and Hcy concentration are predictors of MMA concentration. These findings could help to understand how genetic variation impacts folate metabolism and what metabolic consequences these variants have in individuals with trisomy 21. © Springer Science+Business Media B.V. 2012.391092779284Lejeune, J., Gautier, M., Turpin, R., Study of somatic chromosomes from 9 mongoloid children (1959) C R Hebd Seances Acad Sci, 248 (11), pp. 1721-1722Pogribna, M., Melnyk, S., Pogribny, I., Chango, A., Yi, P., James, J., Homocysteine metabolism in children with Down syndrome: In vitro modulation (2001) Am J Hum Genet, 69 (1), pp. 88-95Coppus, A.W., Fekkes, D., Verhoeven, W.M., Tuinier, S., Egger, J.I., Van Duijn, C.M., Plasma amino acids and neopterin in healthy persons with Down's syndrome (2007) J Neural Transm, 114 (8), pp. 1041-1045Biselli, J.M., Goloni-Bertollo, E.M., Haddad, R., Eberlin, M.N., Pavarino-Bertelli, E.C., The MTR A2756G polymorphism is associated with an increase of plasma homocysteine concentration in Brazilian individuals with Down syndrome (2008) Braz J Med Biol Res, 41 (1), pp. 34-40Licastro, F., Marocchi, A., Penco, S., Porcellini, E., Lio, D., Dogliotti, G., Does Down's syndrome support the homocysteine theory of atherogenesis? Experience in elderly subjects with trisomy 21 (2006) Arch Gerontol Geriatr, 43 (3), pp. 317-318Haddad, R., Mendes, M.A., Hoehr, N.F., Eberlin, M.N., Amino acid quantitation in aqueous matrices via trap and release membrane introduction mass spectrometry: Homocysteine in human plasma (2001) Analyst, 126, pp. 1212-1215De Andrade, C.R., Fukada, S.Y., Olivon, V.C., De Godoy, M.A., Haddad, R., Eberlin, M.N., Alpha1D-adrenoceptor-induced relaxation on rat carotid artery is impaired during the endothelial dysfunction evoked in the early stages of hyperhomocysteinemia (2006) Eur J Pharmacol, 543 (1-3), pp. 83-91Carvalho, V.M., Kok, F., Determination of serum methylmalonic acid by alkylative extraction and liquid chromatography coupled to tandem mass spectrometry (2008) Anal Biochem, 381 (1-3), pp. 67-73Measurement and use of total plasma homocysteine (1998) Am J Hum Genet, 63, pp. 1541-1543. , American Society of Human Genetics/American College of Medical Genetics Test and Technology Transfer Committee Working Group. ASHG/ACMG StatementKlee, G.G., Cobalamin and folate evaluation: Measurement of methylmalonic acid and homocysteinevs vitamin B (12) and folate (2000) Clin Chem, 46 (8 PART 2), pp. 1277-1283Miller, S.A., Dykes, D.D., Polesky, H.F., A simple salting out procedure for extracting DNA from human nucleated cells (1988) Nucleic Acids Res, 16 (3), p. 1215Dutta, S., Sinha, S., Chattopadhyay, A., Gangopadhyay, P.K., Mukhopadhyay, J., Singh, M., Cystathionineβ-synthase T833C/844INS68 polymorphism: A family-based study on mentally retarded children (2005) Behav Brain Funct, 1, p. 25Födinger, M., Dierkes, J., Skoupy, S., Röhrer, C., Hagen, W., Puttinger, H., Effect of glutamate carboxypeptidase II and reduced folate carrier polymorphisms on folate and total homocysteine concentrations in dialysis patients (2003) J Am Soc Nephrol, 14 (5), pp. 1314-1319Frosst, P., Blom, H.J., Milos, R., Goyette, P., Sheppard, C.A., Matthews, R.G., A candidate genetic risk factor for vascular disease: A common mutation in Methylenetetrahydrofolatereductase (1995) Nat Genet, 10 (1), pp. 111-113Hol, F.A., Van Der Put, N.M.J., Geurds, M.P.A., Blom, H.J., Molecular genetic analysis of the gene encoding the trifunctional enzyme MTHFD (methylenetetrahydrofolate-dehydrogenase, methenyltetrahydrofolate- cyclohydrolase, formyltetrahydrofolate synthetase) in patients with neural tube defects (1998) Clin Genet, 53 (2), pp. 119-125Pietrzyk, J.J., Bik-Multanowski, M., 776C>G polymorphism of the transcobalamin II gene as a risk factor for spina bifida (2003) Mol Genet Metab, 80 (3), p. 364Locke, A.E., Dooley, K.J., Tinker, S.W., Cheong, S.Y., Feingold, E., Allen, E.G., Variation in folate pathway genes contributes to risk of congenital heart defects among individuals with Down syndrome (2010) Genet Epidemiol, 34 (6), pp. 613-623Patterson, D., Cabelof, D.C., Down syndrome as a model of DNA polymerase beta haploinsufficiency and accelerated aging (2011) Mech Ageing Dev, , Epub Ahead of PrintFillon-Emery, N., Chango, A., Mircher, C., Barbé, F., Bléhaut, H., Herbeth, B., Homocysteine concentrations in adults with trisomy 21: Effect of B vitamins and genetic polymorphisms (2004) Am J Clin Nutr, 80 (6), pp. 1551-1557Ulvik, A., Ueland, P.M., Fredriksen, A., Meyer, K., Vollset, S.E., Hoff, G., Functional inference of the methylenetetrahydrofolatereductase 677C>T and 1298A>C polymorphisms from a large-scale epidemiological study (2007) Hum Genet, 121 (1), pp. 57-64Laraqui, A., Allami, A., Carrie, A., Coiffard, A.S., Benkouka, F., Benjouad, A., Influence of methionine synthase (A2756G) and methionine synthase reductase (A66G) polymorphisms on plasma homocysteine levels and relation to risk of coronary artery disease (2006) Acta Cardiol, 61 (1), pp. 51-61Feix, A., Fritsche-Polanz, R., Kletzmayr, J., Vychytil, A., Hörl, W.H., Sunder-Plassmann, G., Increased prevalence of combined MTR and MTHFR genotypes among individuals with severely elevated total homocysteine plasma levels (2001) Am J Kidney Dis, 38 (5), pp. 956-964Kluijtmans, L.A., Young, I.S., Boreham, C.A., Murray, L., McMaster, D., McNulty, H., Genetic and nutritional factors contributing to hyperhomocysteinemia in young adults (2003) Blood, 101 (7), pp. 2483-2488Mejia Mohamed, E.H., Tan, K.S., Ali, J.M., Mohamed, Z., TT genotype of the methylenetetrahydrofolate reductase C677T polymorphism is an important determinant for homocysteine levels in multi-ethnic Malaysian ischaemic stroke patients (2011) Ann Acad Med Singapore, 40 (4), pp. 186-191Nagele, P., Meissner, K., Francis, A., Födinger, M., Saccone, N.L., Genetic and environmental determinants of plasma total homocysteine levels: Impact of population-wide folate fortification (2011) Pharmacogenet Genomics, 21 (7), pp. 426-441Weisberg, I.S., Jacques, P.F., Selhub, J., Bostom, A.G., Chen, Z., Curtis Ellison, R., The 1298A→C polymorphism in methylenetetrahydrofolatereductase (MTHFR): In vitro expression and association with Homocysteine (2001) Atherosclerosis, 156 (2), pp. 409-415Bosco, P., Guéant-Rodriguez, R.M., Anello, G., Barone, C., Namour, F., Caraci, F., Methionine synthase (MTR) 2756 (A ->G) polymorphism, double heterozygosity methionine synthase 2756 AG/methionine synthase reductase (MTRR) 66 AG, and elevated homocysteinemia are three risk factors for having a child with Down syndrome (2003) Am J Med Genet A, 121 A (3), pp. 219-224Matteini, A.M., Walston, J.D., Bandeen-Roche, K., Arking, D.E., Allen, R.H., Fried, L.P.C., Transcobalamin-II variants, decreased vitamin B12 availability and increased risk of frailty (2010) J Nutr Health Aging, 14 (1), pp. 73-77Pajares, M.A., Pérez-Sala, D., Betainehomocysteine S-methyltransferase: Just a regulator of homocysteine metabolism? (2006) Cell Mol Life Sci, 63 (23), pp. 2792-2803Krajinovic, M., MTHFD1 gene: Role in disease susceptibility and pharmacogenetics (2008) Pharmacogenomics, 9 (7), pp. 829-832Li, F., Feng, Q., Lee, C., Wang, S., Pelleymounter, L.L., Moon, I., Human betaine-homocysteine methyltransferase (BHMT) and BHMT2: Common gene sequence variation and functional characterization (2008) Mol Genet Metab, 94, pp. 326-335Ueland, P.M., Choline and betaine in health and disease (2011) J Inherit Metab Dis, 34 (1), pp. 3-15Morin, I., Platt, R., Weisberg, I., Sabbaghian, N., Wu, Q., Garrow, T.A., Common variant in betaine-homocysteinemethyltransferase (BHMT) and risk for spina bifida (2003) Am J Med Genet, 119 A (2), pp. 172-176Weisberg, I.S., Park, E., Ballman, K.V., Berger, P., Nunn, M., Suh, D.S., Investigations of a common genetic variant in betaine-homocysteine methyltransferase (BHMT) in coronary artery disease (2003) Atherosclerosis, 167 (2), pp. 205-214Brouns, R., Ursem, N., Lindemans, J., Hop, W., Pluijm, S., Steegers, E., Polymorphisms in genes related to folate and cobalamin metabolism and the associations with complex birth defects (2008) Prenat Diagn, 28 (6), pp. 485-493Namour, F., Olivier, J., Abdelmouttaleb, I., Adjalla, C., Debard, R., Salvat, C., Transcobalamin codon 259 polymorphism in HT-29 and Caco-2 cells and in Caucasians: Relation to transcobalamin and homocysteine concentration in blood (2001) Blood, 97 (4), pp. 1092-1098Miller, J.W., Ramos, M.I., Garrod, M.G., Flynn, M.A., Green, R., Transcobalamin II 775G>C polymorphism and indices of vitamin B12 status in healthy older adults (2002) Blood, 100 (2), pp. 718-720Castro, R., Barroso, M., Rocha, M., Esse, R., Ramos, R., Ravasco, P., The TCN2 776CNG polymorphism correlates with vitamin B (12) cellular delivery in healthy adult populations (2010) Clin Biochem, 43 (7-8), pp. 645-649Fredriksen, A., Meyer, K., Ueland, P.M., Vollset, S.E., Grotmol, T., Schneede, J., Large-scale population-based metabolic phenotyping of thirteen genetic polymorphisms related to one-carbon metabolism (2007) Hum Mutat, 28 (9), pp. 856-865Aléssio, A.C., Höehr, N.F., Siqueira, L.H., Bydlowski, S.P., Annichino-Bizzacchi, J.M., Polymorphism C776G in the transcobalamin II gene and homocysteine, folate and vitamin B12 concentrations. Association with MTHFR C677T and A1298C and MTRR A66G polymorphisms in healthy children (2007) Thromb Res, 119 (5), pp. 571-577Riedel, B.M., Molloy, A.M., Meyer, K., Fredriksen, A., Ulvik, A., Schneede, J., Transcobalamin polymorphism 67A->G, but not 776C->G, affects serum holotranscobalamin in a cohort of healthy middle-aged men and women (2011) J Nutr, 141 (10), pp. 1784-1790Godbole, K., Gayathri, P., Ghule, S., Sasirekha, B.V., Kanitkar-Damle, A., Memane, N., Maternal one-carbon metabolism, MTHFR and TCN2 genotypes and neural tube defects in India (2011) Birth Defects Res A Clin Mol Teratol, 91 (9), pp. 848-856Lievers, K.J.A., Afman, L.A., Kluijtmans, L.A.J., Boers, G.H.D., Verhoef, P., Den Heijer, M., Polymorphisms in the Transcobalamin gene: Association with plasma homocysteine in healthy individuals and vascular disease patients (2002) Clin Chem, 48 (9), pp. 1383-1389Papoutsakis, C., Yiannakouris, N., Manios, Y., Papaconstantinou, E., Magkos, F., The effect of MTHFR (C677T) genotype on plasma homocysteine concentrations in healthy children is influenced by gender (2006) Eur J Clin Nutr, 60 (2), pp. 155-162De Laet, C., Wautrecht, J.C., Brasseur, D., Dramaix, M., Boeynaems, J.-M., Decuyper, J., Plasma homocysteine concentrations in a Belgian School-age population (1999) Am J Clin Nutr, 69, pp. 968-972Papoutsakis, C., Yiannakouris, N., Manios, Y., Papakonstantinou, E., Magkos, F., Schulpis, K.H., Plasma homocysteine concentrations in Greek children are influenced by an interaction between the methylenetetrahydrofolate Redustase C677T genotype and folate status (2005) J Nutr, 135, pp. 383-388Papandreou, D., Mavromichalis, I., Makedou, A., Rousso, I., Arvanitidou, M., Reference range of total serum homocysteine level and dietary indexes in healthy Greek schoolchildren aged 6-15 years (2006) Br J Nutr, 96 (4), pp. 719-724Monsen, A.L., Ueland, P.M., Homocysteine and methylmalonic acid in diagnosis and risk assessment from infancy to adolescence (2003) Am J Clin Nutr, 78 (1), pp. 7-21Shobha, V., Tarey, S.D., Singh, R.G., Shetty, P., Unni, U.S., Srinivasan, K., Vitamin B 12 deficiency & levels of metabolites in an apparently normal urban south Indian elderly population (2011) Indian J Med Res, 134 (4), pp. 432-439Agência Nacional de Vigilância Sanitária do Brasil, , http://e-legis.anvisa.gov.br/leisref/public, Accessed 02 May 2011Jacques, P.F., Selhub, J., Bostom, A.G., Wilson, P.W.F., Rosenberg, I.H., The effect of folic acid fortification on plasma folate and total homocysteine concentrations (1999) N Engl J Med, 340, pp. 1449-145

High frequencies of plexiform neurofibromas, mental retardation, learning difficulties, and scoliosis in Brazilian patients with neurofibromatosis type 1

A clinical study of Brazilian patients with neurofibromatosis type 1 (NF1) was performed in a multidisciplinary Neurofibromatosis Program called CEPAN (Center of Research and Service in Neurofibromatosis). Among 55 patients (60% females, 40% males) who met the NIH criteria for the diagnosis of NF1, 98% had more than six café-au-lait patches, 94.5% had axillary freckling, 45% had inguinal freckling, and 87.5% had Lisch nodules. Cutaneous neurofibromas were observed in 96%, and 40% presented plexiform neurofibromas. A positive family history of NF1 was found in 60%, and mental retardation occurred in 35%. Some degree of scoliosis was noted in 49%, 51% had macrocephaly, 40% had short stature, 76% had learning difficulties, and 2% had optic gliomas. Unexpectedly high frequencies of plexiform neurofibromas, mental retardation, learning difficulties, and scoliosis were observed, probably reflecting the detailed clinical analysis methods adopted by the Neurofibromatosis Program. These same patients were screened for mutations in the GAP-related domain/GRD (exons 20-27a) by single-strand conformation polymorphism. Four different mutations (Q1189X, 3525-3526delAA, E1356G, c.4111-1G>A) and four polymorphisms (c.3315-27G>A, V1146I, V1317A, c.4514+11C>G) were identified. These data were recently published