Increased frequency of combined methylenetetrahydrofolate reductase C677T and A1298C mutated alleles in spontaneously aborted embryos

The pathogenesis of spontaneous abortion is complex, presumably involving the interaction of several genetic and environmental factors. The methylenetetrahydrofolate reductase (MTHFR) gene C677T and A1298C polymorphisms are commonly associated with defects in folate dependent homocysteine metabolism and have been implicated as risk factors for recurrent embryo loss in early pregnancy. In the present study we have determined the prevalence of combined MTHFR C677T and A1298C polymorphisms in DNA samples from spontaneously aborted embryos (foetal death between sixth and twentieth week after conception) and adult controls using solid-phase minisequencing technique. There was a significant odds ratio of 14.2 (95% CI 1.78-113) in spontaneously aborted embryos comparing the prevalence of one or more 677T and 1298C alleles vs the wild type combined genotype (677CC/1298AA), indicating that the MTHFR polymorphisms may have a major impact on foetal survival. Combined 677CT/1298CC, 677TT/1298AC or 677TT/1298CC genotypes, which contain three or four mutant alleles, were not detected in any of the groups, suggesting complete linkage disequilibrium between the two polymorphisms. The present finding of high prevalence of mutated MTHFR genotypes in spontaneously aborted embryos emphasises the potential protective role of periconceptional folic acid supplementation.     

Mutation A1298C of methylenetetrahydrofolate reductase: risk for early coronary disease not associated with hyperhomocysteinemia

Diminished activity of 5,10 methylenetetrahydrofolate reductase (MTHFR), a regulatory enzyme of homocysteine metabolism, may predispose to coronary artery disease (CAD). In a case-control study we determined the prevalence of two common MTHFR polymorphisms, C677T and A1298C, in 161 male patients under the age of 50 years with angiographically documented CAD and compared it to that in 211 healthy controls. Genotyping was also performed in a random population sample, consisting of 149 men and 121 women at an average age of 40 years. The studied group had classic risk factors of atherosclerosis but did not differ in fasting plasma homocysteine, folic acid, and vitamin B12 levels in either the control group or population sample. The frequency of the 1298C allele was significantly higher in CAD (0.304) than in controls (0.199) or the population sample (0.235). Allele 1298C showed a significant association with early-onset CAD both in homozygotes and in heterozygous carriers. These findings were further supported by comparisons with the population sample. Homozygosity for allele 677T showed a tendency to associate with CAD. Allele 1298C of MTHFR is associated with early-onset CAD (carriers- RR = 1.71, 95% CI: 1.13-2.59; homozygotes- RR = 3.09, 95% CI: 1.36-7.02), even when blood homocysteine levels are not elevated.     

The methylenetetrahydrofolate reductase C677T polymorphism is a major determinant of coffee-induced increase of plasma homocysteine: a randomized placebo controlled study

Some methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms are associated with hyperhomocysteinemia. Trials have shown a plasma homocysteine raising effect of coffee. We determined the effect of a daily intake of 600 ml coffee and a supplementation of 200 microg folic acid or placebo on plasma homocysteine (tHcy) with respect to the MTHFR C677T and A1298C polymorphisms. One hundred and twenty healthy, non-smoking men (22%) and women (78%) aged 29-65 years, took part in a controlled, randomized, blinded study with two intervention periods: i) a coffee-free period of three weeks, ii) 600 ml coffee/day and a supplement of 200 microg folic acid/d or placebo for four weeks. The results showed that tHcy at baseline was significantly higher for the 677TT genotype group compared to the 677CC genotype group (p=0.0045) and that this group responded with significantly larger increase in tHcy upon coffee exposure than the 677CC and 677CT genotype groups (p=0.0045 and p=0.0041, respectively). Supplementation with 200 microg folic acid compared to placebo reduced the tHcy increasing effect of coffee in the 677TT genotype group. The A1298C polymorphism did not affect tHcy concentration significantly at any stage in the study. In conclusion, the homocysteine increasing effect of coffee is particularly seen in individuals with the homozygous 677TT genotype. Supplementation with 200 microg folic acid/d decreases this tHcy increment.     

Dizygotic twinning is not associated with methylenetetrahydrofolate reductase haplotypes

BACKGROUND: Folate metabolism is critical to embryonic development, influencing neural tube defects (NTD) and recurrent early pregnancy loss. Polymorphisms in 5,10-methylenetetrahydrofolate reductase (MTHFR) have been associated with dizygotic (DZ) twinning through pregnancy loss. METHODS: The C677T and A1298C polymorphisms in MTHFR were genotyped in 258 Australasian families (1016 individuals) and 118 Dutch families (462 individuals) of mothers of DZ twins and a population sample of 462 adolescent twin families (1861 individuals). Haplotypes were constructed from the alleles, and transmission of the MTHFR haplotypes to mothers of DZ twins and from parents to twins in the adolescent twin families analysed. RESULTS: The C677T and A1298C were common in all three populations (frequencies > 0.29). There was strong linkage disequilibrium (D' = 1) between the variants, showing that specific combinations of alleles (haplotypes) were transmitted together. Three haplotypes accounted for nearly all the variation. There was no evidence of any association between MTHFR genotype and twinning in mothers of twins, or of the loss of specific MTHFR genotypes during twin pregnancies. CONCLUSIONS: It is concluded that variation in twinning frequency is not associated with MTHFR genotype.     

神经管畸形与MTHFRC677T、MTHFRA1298C、MSA2756G基因多态性的相关性研究

目的对MTHFRC677T、MTHFRA1298C、MSA2756G基因的多态性进行综合性分析,了解这3个基因多态性位点同神经管畸形发生的关系,明确神经管畸形发生的遗传学基础,为制定有效的预防及筛查方案提供依据.方法采用PCR-RFLP技术,对50例有两次或两次以上神经管畸形生育史的妇女及40例有正常生育史的妇女,MTHFRC677T、MTHFRA1298C、MSA2756G进行多态性研究.结果①MTHFRC677T及MTHFRA1298C基因型构成在病例组与对照组之间均存在显著性差异,而MSA2756G在两组之间无显著性差异.②MTHFR677TT、MTHFR1298CC和MS2756GGG中任意两种纯和突变并存时OR值明显增加.结论MTHFR677TT基因型和MTHFR1298CC基因型均可能是神经管畸形的危险因素;MS2756GG基因型虽不是独立危险因素,但与其它突变并存时会增加神经管畸形的危险性.     

Methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms and age of onset in schizophrenia: A combined analysis of independent samples

Methylenetetrahydrofolate reductase (MTHFR) is involved in the one‐carbon cycle, which is of importance for nucleotide synthesis and methylation of DNA, membranes, proteins and lipids. The MTHFR gene includes two common polymorphisms (rs1801133 or C677T; rs1801131 or A1298C) which both alter enzyme activity. The T‐allele of the C677T polymorphism has recently been associated with earlier age at onset of schizophrenia. In the present study we examined the association between the MTHFR C677T and A1298C polymorphisms and age at onset of schizophrenia in twelve samples consisting of 3,213 unrelated schizophrenia patients, including the original Scandinavian sample. There was no consistent relationship between MTHFR C677T, A1298C or combined 677T/1298C carriers and age of onset in schizophrenia when the results of each study were combined using meta‐analysis. The present results suggest that the investigated MTHFR polymorphisms do not influence age of onset in schizophrenia. © 2011 Wiley‐Liss, Inc.     

Serum homocysteine, vitamin B12, folic acid levels and methylenetetrahydrofolate reductase (MTHFR) gene polymorphism in vitiligo

The aim of this study was to determine serum vitamin B12, folic acid and homocysteine (Hcy) levels as well as MTHFR (C677, A1298C) gene polymorphisms in patients with vitiligo, and to compare the results with healthy controls. Forty patients with vitiligo and 40 age and sex matched healthy subjects were studied. Serum vitamin B12 and folate levels were determined by enzyme-linked immunosorbent assay. Plasma Hcy levels and MTHFR polymorphisms were determined by chemiluminescence and real time PCR methods, respectively. Mean serum vitamin B12 and Hcy levels were not significantly different while folic acid levels were significantly lower in the control group. There was no significant relationship between disease activity and vitamin B12, folic acid and homocystein levels. No significant difference in C677T gene polymorphism was detected. Heterozygote A1298C gene polymorphism in the patient group was statistically higher than the control group. There was no significant relationship between MTHFR gene polymorphisms and vitamin B12, folic acid and homocysteine levels. In conclusion, vitamin B12, folate and Hcy levels are not altered in vitiligo and MTHFR gene mutations (C677T and A1298C) do not seem to create susceptibility for vitiligo.     

MTHFR、MTRR基因多态性与反复流产的相关性分析

目的探讨叶酸代谢相关基因5,10-亚甲基四氢叶酸还原酶(MTHFR)、甲硫氨酸合成酶还原酶(MTRR)多态性与反复流产的关系,分析基因多态性对红细胞叶酸水平的影响。方法选取2016年12月至2018年6月来唐山市妇幼保健院遗传咨询门诊,要求进行常规孕前检查,汉族非妊娠健康女性424例为研究对象。依据不良孕产史分为两组,其中病例组216例和对照组218例。采集静脉血,提取DNA,荧光定量PCR法进行MTHFR、MTRR基因多态性检测。化学发光法进行红细胞叶酸定量检测。采用SPSS19.0软件进行统计学分析。比较两组MTHFR、MTRR基因多态性分布频率、不同基因类型红细胞叶酸水平。探讨基因多态性、红细胞叶酸水平与反复流产的关系。结果MTHFR A1298C和MTRR A66G两位点多态性在病例组和对照组间的分布,差异无统计学意义。MTHFR C677T位点多态性,在病例组中的分布频率明显高于对照组,差异具有统计学意义。病例组中MTHFR C667T位点TT型基因突变的患者红细胞叶酸水平远低于正常和杂合型。结论MTHFR C677T基因突变与反复流产的密切相关,MTHFR C667T位点TT型基因突变影响机体红细胞叶酸代谢水平。     

Genotype and haplotype distributions of MTHFR677C>T and 1298A>C single nucleotide polymorphisms: a meta-analysis

Common single nucleotide polymorphisms (SNPs; 677C>T and 1298A>C) in the methylenetetrahydrofolate reductase gene ( MTHFR) decrease the activity of the enzyme, leading to hyperhomocysteinemia, particularly in folate-deficient states. We calculate herein the haplotype frequencies of the MTHFR 677 and 1298 polymorphisms in pooled general populations derived from published data. We selected 16 articles that provided reliable data on combined MTHFR genotypes in general populations ( n = 5389). The combined data comprised the following totals for each genotype at nucleotide positions 677 and 1298: 838 CC/AA (i.e., 677CC/1298AA), 1225 CC/AC, 489 CC/CC, 1120 CT/AA, 1093 CT/AC, 8 CT/CC, 606 TT/AA, 10 TT/AC, and 0 TT/CC. The estimated haplotype frequencies, and the fractional contribution of each, were 677C/1298A, 0.37; 677C/1298C, 0.31; 677T/1298A, 0.32; and 677T/1298C, 0.0023 to 0.0034. Thus, a vast majority of 677T alleles and 1298C alleles are associated with 1298A alleles and 677C alleles, respectively. There may be an increased frequency of the very rare cis 677T/1298C haplotype in some parts of the United Kingdom and Canada, possibly due to a founder effect. Further studies on both SNPs are needed to determine their exact role in various clinical settings.     

No association of functional polymorphisms in methlylenetetrahydrofolate reductase and the risk and minor physical anomalies of schizophrenia in Korean population

Methylenetetrahydrofolate reductase (MTHFR), a critical enzyme in folate metabolism, plays an important role in DNA methylation. It has been suggested that abnormal DNA methylation contributes to the pathogenesis of schizophrenia and congenital anomalies. The previous findings regarding the genetic relationship between MTHFR and schizophrenia are controversial. This study investigated the association of the two functional polymorphisms of MTHFR, C677T and A1298C, with the risk for schizophrenia. Furthermore, we conducted an updated meta-analysis on the two polymorphisms. In addition, we investigated the relationship between the polymorphisms and minor physical anomaly (MPA), which may represent neurodevelopmental aberrations in 201 schizophrenia patients and 350 normal control subjects. There was no significant association between either of the two polymorphisms and the risk of schizophrenia (chi-square = 0.001, df = 1, P = 0.971 for C677T; chi-square = 1.319, df = 1, P = 0.251 for A1298C). However, in meta-analysis, the C677T polymorphism showed a significant association in the combined and Asian populations (OR = 1.13, P = 0.005; OR = 1.21, P = 0.011, respectively) but not in the Korean and Caucasian populations alone. Neither polymorphism was associated with MPAs measured by the Waldrop scale (chi-square = 2.513, df = 2, P = 0.285). In conclusion, the present findings suggest that in the Korean population, the MTHFR polymorphisms are unlikely to be associated with the risk for schizophrenia and neurodevelopmental abnormalities related to schizophrenia.     

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

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

Genotypes of the C677T and A1298C polymorphisms of the MTHFR gene as a cause of human spontaneous embryo loss

BACKGROUND Polymorphisms C677T and A1298C of the MTHFR gene have been implicated in fetal viability. In this study, we determined the allele and genotype frequencies of these polymorphisms in different populations, including spontaneous abortion (SA) fetal tissues, with the objective of evaluating their impact on fetal viability. METHODS 342 samples of fetal tissues, selected from SA occurring during the 1980s, 230 samples from subjects born in the 1980s and a third set of samples from 204 subjects born in the 1950s, were genotyped by using TaqMan probes. RESULTS The wild CC genotype of the C677T polymorphism showed a strong protective effect against abortion (0.03 in SA versus 0.47 in 1950s and 0.43 in 1980s) (P < 0.0001). Genotypes of three mutations in the combinations of polymorphisms for C677T and A1298C showed a very low frequency in the living population; however, the three mutations genotypes were over expressed in the SA group (0.02 in 1950s; 0.03 in 1980s and 0.17 in SA) (P < 0.0001). Samples with four mutations (n = 2) were found only in the SA group. CONCLUSIONS There is no linkage disequilibrium between C667T and A1298C polymorphisms. Fetal viability is directly related to the CC genotype as a protector while the three and four mutation MTHFR genotypes appear to be a determinant on fetal non-viability and SA.     

Polymorphisms of methylenetetrahydrofolate reductase and methionine synthase genes and bladder cancer risk: a case–control study with meta-analysis

Folate deficiency due to the methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MS) variants leads to carcinogenesis by affecting DNA synthesis, repair, and methylation. We hypothesized that the MTHFR C677T, A1298C, and MS A2756G polymorphisms are associated with risk of bladder cancer. In a case-control study of 239 bladder cancer cases and 250 cancer-free controls, we found that the MTHFR 677TT genotype was statistically significantly associated with an increased risk of bladder cancer compared with the 677CC genotype (OR = 2.06, 95% CI = 1.16-3.64). Furthermore, the TA haplotype was associated with a significantly increased bladder cancer risk (OR = 1.38, 95% CI = 1.05-1.81) than was the most common haplotype, CA (e.g., CA denotes MTHFR 677C -1298A). We also found that the combined genotypes with 4-6 variant (risk) alleles (i.e., MTHFR 677T, 1298A, and MS 2756G alleles) were associated with an increased risk of bladder cancer (OR = 1.62, 95% CI = 1.03-2.53) compared with those with 0-3 variants, and this increased risk was more pronounced among subgroup of older people (OR = 1.71, 95% CI = 1.03-2.83). A meta-analysis of seven studies did not show a significant risk of bladder cancer in the MTHFR polymorphisms. The MTHFR polymorphisms and their haplotypes appear to jointly contribute to risk of bladder cancer.     

Associations of MTHFR DNMT3b 4977 bp deletion in mtDNA and GSTM1 deletion, and aberrant CpG island hypermethylation of GSTM1 in non-obstructive infertility in Indian men

Methylenetetrahydrofolate (MTHFR) and DNMT3b play imperative roles in DNA synthesis and de novo methylation. GSTM1 is involved in detoxification of carcinogens. Mitochondrial DNA deletion has been associated with lower motility in human sperm. We analysed if polymorphisms in MTHFR (C677T and A1298C) and DNMT3b (C46359T) are associated with non-obstructive male infertility. We also analysed if folate, vitamin B(12), homocysteine (Hcy), 8'-hydroxy-2'-deoxygnanosine (8-OHdG) levels, dietary folate intake and mtDNA deletion (4977 bp) affects fertility, such interactions are modified by deletion and methylation of GSTM1. In this case-control study, we included 179 oligoasthenoteratozoospermia patients and 200 fertile men. Single-nucleotide polymorphism analysis was performed by PCR-restriction fragment length polymorphism. The MTHFR (C677T and A1298C) and DNMT3b (C46359T) frequencies did not differ significantly in two groups. GSTM1 in association with mtDNA 4977 deletion is significantly associated with infertility. Plasma folate and vitamin B(12) levels are decreased and total Hcy is elevated in infertile men. GSTM1 methylation status was investigated by methylation-specific PCR. Methylation is significantly correlated with GSTM1 reduced/loss of expression in infertile men. Infertile men have significantly higher 8-OHdG levels. Dietary folate intake is not linked with GSTM1 methylation. Low folate intake in association with CT + TT genotypes (C677T) has significant protective effect on GSTM1 methylation. Results indicate that micronutrients, 8-OHdG levels, mtDNA deletion and GSTM1 promoter methylation are frequent alterations in infertility.     

Association of methylenetetrahydrofolate reductase C677T and A1298C polymorphisms with myocardial infarction in Tunisian young patients

Myocardial infarction (MI) is an important clinical problem because of its large contribution to mortality. The objective of this study is to assess whether two methylenetetrahydrofolate reductase (MTHFR) polymorphisms, C677T and A1298C, were associated with MI among Tunisian patients. One hundred young patients (<47 years old) with MI were recruited and compared with 200 control subjects with no history of MI. The most common MI risk factors were investigated. Fasting plasma homocysteine levels were measured. Genotypes of the MTHFR C677T and A1298 polymorphisms were studied by polymerase chain reaction. The mean plasma homocysteine level in the study group was raised when compared with the control group. Homozygous MTHFR C677T mutation was observed in 2 (2 %) patients and in 17 (8.5 %) control subjects, whereas heterozygous MTHFR C677T mutation was detected in 82 (82 %) patients versus only 79 (39.5 %) in control subjects. The mean total homocysteine concentrations were significantly higher in individuals with the 677TT and CT genotypes. Our results indicate that C677T and A1298C MTHFR mutations and hyperhomocysteinemia contributed to the risk factors for MI.     

贵州荔波汉族与雷山苗族MTHFR基因多态性分布的比较

目的比较贵州汉族、苗族亚甲基四氢叶酸还原酶基因(MTHFR)多态性的分布情况,获取 MTHFR C677T和A1298C位点的群体遗传学数据.方法应用PCR-RLFP技术调查了贵州荔波汉族及雷山苗族MTHFR基因型的分布.结果汉族MTHFR 677位T等位基因频率为22.7%低于中国北方汉族,与苗族(10.64%)差异有显著性.苗族1298位C等位基因频率为48.66%高于有文献报道的种族和民族,与汉族(28.85%)差异有显著性.677TT/1298CC双杂合子的分布频率分别是16.66%,11.11%.在苗族还发现一例677TT/1298CC双纯合子.结论 MTHFR两个位点多态性在贵州汉族和苗族有民族差异;苗族A1298C位点C等位基因频率是有文献报道最高的民族.     

Methylenetetrahydrofolate reductase enzyme polymorphisms as maternal risk for Down syndrome among Turkish women

Advanced maternal age is the only fully accepted risk factor for trisomy 21, while most children with Down syndrome (DS) are born to younger mothers (<35 years). The relationship between chromosomal nondisjunction leading to aneuploidy and folate metabolism has drawn attention in the recent years. In this study, we examined the two polymorphisms in genes encoding the folate metabolizing enzyme methylenetetrahydrofolate reductase (MTHFR), namely, 677C > T and 1298A > C. The prevalence of these variant genotypes in mothers of DS children (case mothers) (n = 152) was compared with controls (n = 91). Frequencies of MTHFR 677C > T genotypes (CC, CT, and TT) and also combination of heterozygous and homozygous variant genotypes (CT or TT) (P = 0.28) demonstrated no difference between the case and control groups. Genotype frequencies of MTHFR 1298A > C (AA, AC, and CC) were similar among the case and control mothers. Variant genotypes of MTHFR 1298A > C (AC or CC) were also insignificant when compared between the two groups. This is yet the largest case-control study conducted for MTHFR 677C > T and also the first to investigate a possible relation with MTHFR 1298A > C. The data presented in this study fail to support the relationship between MTHFR 677C > T and 1298A > C polymorphisms and risk of having a child with DS.     

Prevalence of MTHFR gene polymorphisms (C677T and A1298C) among Tamilians

We have investigated the incidence of the C677T and A1298C methylene tetrahydrofolate reductase (MTHFR) gene single nucleotide polymorphisms (SNPs) in the South Indian Tamil Nadu population with a total number of 72 individuals. The MTHFR genotyping was performed using the polymerase chain reaction followed by restriction enzyme analysis. Homozygosity for the MTHFR A1298C SNP was detected in 15.3% (11/72) of the individuals tested, and 47.2% (34/72) were heterozygous for this SNP. Homozygosity for the C677T MTHFR SNP was detected in 1.38%(1/72), and the frequency of the C677T heterozygotes was 18.1%(13/72). When we analyzed the combined frequency of the two SNPs, the frequency of double heterozygosity was19.6%, and the frequency of double homozygosity was completely absent among the study group. The 'C' allele frequency for MTHFR A1298C was 0.389, and the 'T' allele frequency for C677T mutation was 0.104. Out of the 72 individuals included in the study, 52 were acute myocardial infarction (AMI) patients and 20 were healthy individuals with no documented history of heart disease. The results of this study indicate that the MTHFR A1298C SNP is more prevalent among the Tamilians when compared to the MTHFR C677T SNP, suggesting a possible role of MTHFR A1298C in the pathogenesis of heart diseases.     

MTHFR C677T, MTHFR A1298C, and OPG A163G polymorphisms in Mexican patients with rheumatoid arthritis and osteoporosis

MTHFR polymorphisms C677T and A1298C are associated with reduced MTHFR enzyme activity and hyperhomocysteinemia, which has been associated with osteoporosis. The A163G polymorphism in osteoprotegerin (OPG) has been studied in osteoporosis with controversial results. The objective of the present study was to investigate the association(s) among MTHFR C677T, MTHFR A1298C, and OPG A163G polymorphisms in Mexican patients with rheumatoid arthritis and osteoporosis. The femoral neck and lumbar spine bone mineral densities (BMDs) were measured in 71 RA patients, and genotyping for the three polymorphisms was performed via restriction fragment length polymorphism analysis. Patients with osteoporosis/osteopenia exhibited statistically significant differences in the genotype frequencies of MTHFR C677T as well as an association with femoral neck BMD; TT homozygotes had lower BMDs than patients with the CT genotype, and both of these groups had lower BMDs than patients with the CC genotype. The associations of the MTHFR C677T polymorphism with osteoporosis/osteopenia and femoral neck BMD suggest that these polymorphisms confer a risk of developing osteoporosis in patients with rheumatoid arthritis, a risk that may be reduced with folate and B complex supplementation.     

The clinical significance of methylenetetrahydrofolate reductase (MTHFR) polymorphisms in acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy. Genetic polymorphisms in the folate metabolic pathway may contribute to the susceptibility to childhood ALL because they affect the DNA synthesis, methylation, and repair. The most common polymorphisms are methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C. The current study aimed at detecting the frequency of these two genetic polymorphisms in de novo ALL patients, and to clarify their impact on the response to induction chemotherapy, as well as treatment toxicity. MTHFR C677T and A1298C polymorphisms were tested in 30 de novo ALL patients by restriction fragment length polymerase chain reaction technique. Thirty normal age- and sex-matched subjects were subjected to the same analysis as a control group. The frequency of MTHFR A1298C gene polymorphism was significantly lower in ALL patients than the controls thus showing a protective effect. The two polymorphisms had no effect on the response to induction chemotherapy. As regards the treatment toxicity, MTHFR C677T polymorphism was associated with marked thrombocytopenia, while A1298C polymorphism was associated with hepatic toxicity. Identifying predictors of methotrexate sensitivity may lead to the development of individualized treatment strategies with improved efficacy and reduced toxicity as well as adjusting the initial methotrexate dose.