Efficacy and toxicity of methotrexate in early rheumatoid arthritis are associated with single‐nucleotide polymorphisms in genes coding for folate pathway enzymes

Objective

To determine associations of methotrexate (MTX) efficacy and toxicity with single‐nucleotide polymorphisms (SNPs) in genes coding for folate pathway enzymes in patients with early rheumatoid arthritis (RA).

Methods

Patients (n = 205) with active RA received MTX at an initial dosage of 7.5 mg/week, which was increased to 15 mg/week and combined with folic acid (1 mg/day) after 4 weeks. If the Disease Activity Score in 44 joints (DAS44) was >2.4 at 3 months, MTX was increased to 25 mg/week. MTX efficacy was evaluated at 3 and 6 months and compared for genotypes in 3 analyses: patients with and without good response (DAS44 ≤2.4), patients with and without good improvement (ΔDAS44 >1.2), and patients with and without moderate improvement (ΔDAS44 >0.6). The association between MTX‐related adverse drug events (ADEs) and genotype was evaluated by comparing genotypes between patients with and without ADEs, specifically pneumonitis, gastrointestinal ADEs, skin and mucosal ADEs, and elevated liver enzyme levels. The following SNPs were analyzed: methylenetetrahydrofolate reductase (MTHFR) 677C>T, MTHFR 1298A>C, dihydrofolate reductase (DHFR) −473G>A, DHFR 35289G>A, and reduced folate carrier 80G>A. In case of significant differences, odds ratios (ORs) were calculated.

Results

At 6 months, MTHFR 1298AA was associated with good improvement relative to 1298C (OR 2.3, 95% confidence interval [95% CI] 1.18–4.41), which increased with increased copies of the MTHFR 677CC haplotype. In contrast, MTHFR 1298C allele carriers developed more ADEs (OR 2.5, 95% CI 1.32–4.72).

Conclusion

Patients with MTHFR 1298AA and MTHFR 677CC showed greater clinical improvement with MTX, whereas only the MTHFR 1298C allele was associated with toxicity. In the future, MTHFR genotypes may help determine which patients will benefit most from MTX treatment.

     

Methylenetetrahydrofolate reductase polymorphisms, C677T and A1298C, are associated with methotrexate-related toxicities in Korean patients with rheumatoid arthritis

We investigated associations between the methylenetetrahydrofolate reductase (MTHFR) polymorphisms C677T and A1298C and methotrexate (MTX)-related toxicities in Korean patients with rheumatoid arthritis (RA) taking MTX. One hundred sixty-seven patients with RA were enrolled in a cross-sectional study and genotyped for the single-nucleotide polymorphisms C677T and A1298C in MTHFR. Alleles, genotypes, and haplotypes of the C677T and A1298C polymorphisms were not associated with specific MTX toxicities. However, among RA patients with the 1298CC genotype, the proportion who experienced at least one toxicity was significantly greater than the proportion of patients with 1298AA who did (P?=?0.043). In addition, the proportion of patients with the 677C/1298A haplotype who experienced toxicity was greater than the proportion of those with 677C/1298C who did (P?=?0.032, odds ratio?=?2.085, 95% confidence interval 1.058–4.106). In this study, MTHFR polymorphisms were associated with MTX toxicities in Korean patients with RA. Further study for association of MTHFR polymorphisms with MTX toxicities should be needed in larger RA population.     

Effect of polymorphisms in folate-related genes on in vitro methotrexate sensitivity in pediatric acute lymphoblastic leukemia

We studied whether common polymorphisms in genes involved in folate metabolism affect methotrexate (MTX) sensitivity. Ex vivo MTX sensitivity of lymphoblasts obtained from pediatric patients with acute lymphoblastic leukemia (ALL; n = 157) was determined by the in situ thymidylate synthase inhibition assay after either continuous (21 hours; TSI(50, cont)) or short-term (3 hours; TSI(50, short)) MTX exposure. DNA was isolated from lymphoblasts obtained from cytospin slides. Polymorphisms in methylenetetrahydrofolate reductase (MTHFR 677C>T, MTHFR 1298A>C), methionine synthase (MTR 2756A>G), methionine synthase reductase (MTRR 66A>G), methylenetetrahydrofolate dehydrogenase (MTHFD1 1958G>A), serine hydroxymethyl transferase (SHMT1 1420C>T), thymidylate synthase (TS 2R3R), and the reduced folate carrier (RFC 80G>A) were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) or real-time PCR. Patients with the MTHFR 1298AC variant or the MTRR 66 G-allele showed decreased in vitro MTX sensitivity measured under both test conditions. SHMT1 1420TT homozygotes only showed decreased MTX sensitivity in the TSI(50, cont). In conclusion, polymorphisms in the folate-related genes MTHFR, MTRR, and SHMT1 are related to MTX resistance in pediatric patients with ALL.     

Dietary factors and biomarkers involved in the methylenetetrahydrofolate reductase genotype-colorectal adenoma pathway

BACKGROUND & AIMS: Methylenetetrahydrofolate reductase (MTHFR) is involved in intracellular folate homeostasis and metabolism. We assessed 2 polymorphisms in the MTHFR gene (C677T and A1298C) in relation to colorectal adenoma recurrence and conducted analyses to investigate their joint effects with plasma and dietary markers of folate status. METHODS: We prospectively analyzed data from 1598 individuals genotyped for the C677T polymorphism and 1583 with data on A1298C. RESULTS: Among nonusers of multivitamin supplements, compared with wild-type carriage, higher odds of recurrence were observed for those with the 677 TT variant (odds ratio [OR], 1.66; 95% confidence interval [CI], 1.04-2.63) and a nonsignificant increase was observed among those with the 1298 CC variant (OR, 1.50; 95% CI, 0.93-2.40). Diplotype analyses among nonusers of multivitamins showed that individuals who carry the MTHFR 677TT_1298AA or 677CC_1298CC combination were significantly more likely to have a recurrence compared with those with the double wild-type (OR, 2.05 for TT_AA and 1.85 for CC_CC). Higher odds of recurrence were observed among participants with low folate intake or plasma folate and the 677 TT or 1298 CC variants compared with those with lower levels and the wild-type or heterozygous genotypes. Stronger associations were shown for the combination of high homocysteine and the 677 TT variant (OR, 2.29; 95% CI, 1.00-5.26) but not the 1298 CC variant (OR, 1.09; 95% CI, 0.39-3.01). CONCLUSIONS: We propose that the effect of the MTHFR genotypes on increasing risk of adenoma recurrence in the presence of a low folate status is through their increase in homocysteine concentrations, which in turn could result in DNA hypomethylation via pathways involving S-adenosylhomocysteine.     

Influence of methylenetetrahydrofolate reductase polymorphisms on efficacy and toxicity of methotrexate in patients with juvenile idiopathic arthritis

OBJECTIVE: To study the relationship of C677T and A1298C polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene to toxicity and efficacy of methotrexate (MTX) in patients with juvenile idiopathic arthritis (JIA). METHODS: Single nucleotide polymorphisms of the MTHFR gene were investigated by polymerase chain reaction and restriction enzyme analysis of DNA extracted from peripheral blood cells. The fasting plasma homocysteine concentration was analyzed by enzyme immunoassay. Clinical data of 58 patients with JIA treated with MTX were analyzed retrospectively. RESULTS: The 1298A/A genotype was present in 31 patients, 1298C/C in 4 patients, and 21 patients were heterozygous. The 677C/C genotype was present in 29 patients, 677 T/T in 3 patients, and 26 patients were heterozygous. In patients who presented the C allele of the A1298C polymorphism, improvement with respect to the number of swollen joints, the number of tender joints, and a decrease in erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels occurred more frequently than in 1298 A/A homozygous patients (p < 0.05 for ESR, p < 0.01 for CRP, chi-square test). There was no relationship between the C677T polymorphism and the efficacy of MTX treatment. Forty-two adverse events were noted in 26 patients; gastrointestinal symptoms were most common (n = 20), followed by elevated serum levels of transaminases (n = 19) and hair loss (n = 3). There was no cytopenia. Patients with the heterozygous genotype 677C/T exhibited adverse events more frequently than patients with the homozygous C/C genotype (65% vs 31%; p < 0.05, chi-square test). The A1298C polymorphism, however, was not associated with occurrence of adverse events. Plasma homocysteine was elevated in 6 patients with up to 16.9 mmol/l. No association was found to a specific genotype or to adverse events. CONCLUSION: These preliminary data suggest an association of the MTHFR 677C/C polymorphism to a higher tolerability of MTX, and of the 1298A/A to lower clinical efficacy of MTX therapy in JIA.     

Association of the MTHFR C677T and A1298C polymorphisms with methotrexate toxicity in rheumatoid arthritis: a meta-analysis

The aim of this study was to explore whether the C677T and A1298C polymorphisms of methylenetetrahydrofolate reductase (MTHFR) play a role in methotrexate (MTX) toxicity in rheumatoid arthritis (RA). MEDLINE and EMBASE database searches and subsequent manual searches were utilized to identify articles in which C677T and A1298C MTHFR polymorphisms were evaluated in RA patients taking MTX. A meta-analysis was conducted to identify associations between MTHFR polymorphisms and MTX toxicity. Twelve studies comprising a total of 2,288 RA patients were included in our meta-analysis. Meta-analysis revealed an association between the overall toxicity of MTX and the MTHFR 677TT genotype (odds ratio [OR]?=?1.615, 95 % confidence interval [CI]?=?1.185–2.200, p?=?0.002). Stratification by ethnicity indicated an association between the MTHFR 677TT genotype and the overall toxicity of MTX in East Asians (OR?=?1.583, 95 % CI?=?1.075–2.331, p?=?0.020). The toxicity of MTX also was found to be associated with the TT genotype in patients taking folate (OR?=?1.893, 95 % CI?=?1.283–2.793, p?=?0.001). Stratification by toxicity type indicated an association between the MTHFR 677TT genotype and any adverse effects (OR?=?1.716, 95 % CI?=?1.127–2.612, p?=?0.012). Meta-analysis stratified by toxicity type indicated an association between the MTHFR 1298CC genotype and any adverse effects (OR?=?0.501, 95 % CI?=?0.284–0.886, p?=?0.017). The results of our meta-analysis suggest that the MTHFR C677T and A1298C polymorphisms are associated with MTX toxicity in RA patients.     

Pharmacogenomic and metabolic biomarkers in the folate pathway and their association with methotrexate effects during dosage escalation in rheumatoid arthritis

OBJECTIVE: To evaluate the contribution of metabolites (methotrexate [MTX] and folate polyglutamate [PG] levels) and pharmacogenetic biomarkers in the folate pathway to the effects of MTX in patients with rheumatoid arthritis not previously treated with this antifolate. METHODS: Forty-eight MTX-naive adult patients were enrolled in a prospective longitudinal study. MTX therapy was initiated at 7.5 mg/week and was increased every 4-6 weeks until a therapeutic response was achieved. Response was assessed using the Disease Activity Score in 28 joints (DAS28). Red blood cell (RBC) MTX and folate PG levels were measured with 9 common polymorphisms in the folate pathway. Statistical analyses consisted of generalized linear models and multivariate regressions. RESULTS: After 6 months of therapy, the median weekly MTX dosage was 17.5 mg and the median decrease in the DAS28 was 2.0. There was a large interpatient variability in RBC MTXPG levels (median 35 nmoles/liter [interquartile range 28-51] at month 6). Patients with a lesser decrease in the DAS28 (fewer improvements) had lower RBC MTXPG levels (P < 0.05) despite the higher MTX dose administered (P < 0.05). RBC folate PG levels decreased significantly during treatment, and a lesser decrease in RBC folate PGs was associated with a lesser decrease in the DAS28 (P < 0.05). Primary side effects were gastrointestinal and neurologic in nature. Risk genotypes associated with toxicity were in gamma-glutamyl hydrolase (-401CC), 5-aminoimidazole-4-carboxamide ribonucleotide transformylase (347GG), methylenetetrahydrofolate reductase (1298AC/CC), methionine synthase (2756AA), and methionine synthase reductase (66GG). CONCLUSION: RBC MTXPG levels are a useful means by which to monitor therapy. The genetic associations presented generate hypotheses, and confirmation in independent cohorts is warranted.     

Methotrexate-induced mucositis in acute leukemia patients is not associated with the MTHFR 677T allele in Mexico

Methylenetetrahydrofolate reductase (MTHFR) has two common variants with reduced activity due to polymorphisms at nucleotides 677 and 1298. Both affect folate metabolism and thus remethylation of homocysteine, but are also thought to affect nucleotide synthesis and DNA methylation. Methotrexate (MTX), which interrupts folate metabolism, is used in the treatment of a variety of diseases including acute lymphoblastic leukemia (ALL), but exerts in some patients toxic effects on fast dividing tissues such as mucosal epithelia. The enhanced toxicity may be due to cooperative effects between MTX and MTHFR variants. Accordingly, it has been reported that carrying the 677T allele of the MTHFR is a risk factor for MTX-associated mucositis. As in the Mexican population, which is characterized by a high prevalence of the 677T MTHFR variant, several of its commonly associated defects have not been observed, we investigated the relationship between MTX toxicity and the 677T allele. Out of 28 patients with ALL (CC: 2, CT: 10, TT: 16), 16 had episodes of MTX-associated mucositis (CC: 0, CT: 6, TT: 10). Neither at the gene level nor at the genotype level was a significant association with mucositis found. It may be postulated that the risk of higher MTX toxicity in patients with decreased MTHFR activity could be neutralized by the normally folate rich diet in Mexico.     

类风湿关节炎患者MTHFR基因A1298C、C677T多态性与甲氨蝶呤疗效及不良反应的关系

目的探讨类风湿关节炎（RA）患者亚甲基四氢叶酸还原酶（MTHFR）基因A1298C（rs1801131）、C677T（rs1801133）单核苷酸多态性（SNPs）与甲氨蝶呤（MTX）疗效和不良反应的相关性。方法收集初治活动期RA患者78例，均口服MTX10—15mg／周。观察治疗0周、4周、8周、12周、24周临床症状及实验室指标变化，评价疗效及不良反应。采用实时荧光定量PCR方法检测基因型，分析各等位基因频率与MTX疗效及不良反应的相关性。结果MTHFRA1298C位点的C等位基因频率在治疗有效组明显高于治疗无效组（30．8％VS9．6％，P〈0．05）。C677T位点的T等位基因频率在有不良反应组与无不良反应组间差异有统计学意义（57．8％vs31．8％，P〈0．05）。结论MTHFR基因A1298C多态性与MTX的疗效相关，C677T多态性与MTX不良反应具有相关性。     

Methylenetetrahydrofolate reductase gene C677T and A1298C polymorphisms, plasma homocysteine, folate, and vitamin B12 levels and the extent of coronary artery disease

The question of whether mild hyperhomocysteinemia is a risk factor for coronary artery disease (CAD) has long been debated and is still unclear. We investigated whether there is a link between methylenetetrahydrofolate reductase (MTHFR) gene C677T and A1298C polymorphisms or plasma homocysteine and CAD. This is a case-control study that included 2,121 consecutive patients (cases) with angiographically proved CAD and 617 patients without CAD (controls). MTHFR gene C677T and A1298C polymorphisms, plasma homocysteine, folate, and vitamin B(12) concentrations were determined and coronary angiography was performed in all subjects. The distribution of MTHFR gene C677T genotypes in patients (or controls) was: CC-genotype in 915 cases, 43.1% (266 controls, 43.1%); CT-genotype in 955 cases, 45.0%, (283 controls, 45.9%); and TT-genotype in 251 cases, 11.9% (68 controls, 11.0%) (p = 0.84). The distribution of MTHFR gene A1298C genotypes in patients (or controls) was: AA-genotype in 973 cases, 45.9% (281 controls, 45.5%); AC-genotype in 905 cases, 42.7% (284 controls, 46.0%); and CC-genotype in 243 cases, 11.4% (52 controls, 8.5%) (p = 0.07). Patients with CAD had higher levels of plasma homocysteine (12.9 +/- 5.1 vs 11.9 +/- 4.5 micromol/L, p <0.001) and lower levels of folate (9.5 +/- 3.1 vs 9.9 +/- 3.8 ng/ml, p = 0.008) than controls. After adjustment for other risk factors for CAD, plasma homocysteine (p = 0.89), MTHFR gene C677T (p = 0.38), or A1298C polymorphisms (p = 0.13) were not independent correlates of CAD. This study demonstrated that MTHFR gene C677T or A1298C polymorphisms are not associated with the presence of angiographic CAD. Although there is an apparent association between elevated levels of homocysteine and CAD, this association is not independent of conventional cardiovascular risk factors.     

类风湿关节炎亚甲基四氢叶酸还原酶基因多态性与甲氨蝶呤疗效和不良反应的关系

目的 探讨类风湿关节炎(RA)患者亚甲基四氢叶酸还原酶(MTHFR)基因677CDT[rs1801133)、1298A/C(rs1801131)单核苷酸多态性(SNP)及其与甲氨蝶呤(MTX)治疗的疗效和不良反应相关性.方法 收集RA患者184例.分为单用MTX组、MTX联用其他改善病情抗风湿药(DMARD)组、非MTX的DMARD组,于治疗前及治疗后24周检查临床及实验室指标,评价疗效及不良反应.采用实时荧光定量聚合酶链反应(FQ-PCR)方法检测RA患者及100名健康对照组的MTHFR基因677C/T及1298A/C多态性,比较两组间基因型分布及等位基因频率.结果 677CC/CT/TT基因型分布在RA组(19%、67%、14%)与健康对照组(27%、56%、17%)基因型分布频率差异无统计学意义(P>0.05);1298AA/AC/CC基因型分布在RA组(66%、31%、3%)健康对照组(70%、30%、0%)基因型分布频率差异无统计学意义(P>0.05).677CC/CT/TT基因型分布在RA有心血管并发症组(6%、75%、19%)与正常对照组(27%、56%、17%)差异有统计学意义(P<0.05).在单用MTX治疗者巾,1298AA/AC/CC在MTX治疗有效组(54%、44%、2%)和无效组(90%、10%、O%)中差异有统计学意义(P<0.05),677CC/CT/TT在MTX有不良反应组(13%、71%、16%)和无不良反应组(48%、48%、4%)中差异有统计学意义(P<0.05).在MTX联用其他DMARD组,677CC/CT/TT在有不良反应组(9%、78%、13%)和无不良反应组(35%、50%、15%)中差异有统计学意义(P<0.05).结论 MTHFR基因677C/T及1298A/C多态性与RA发病无关;677 C/T多态性与RA心血管并发症的出现有关、与MTX治疗后的不良反应相关,1298 A/C多态性与MTX的疗效相关.     

Analysis of MTHFR polymorphisms and P16 methylation and their correlation with clinical–biological features of multiple myeloma

Background Low folate intake and changes in folate metabolism due to polymorphisms in the methylentetrahydrofolate reductase (MTHFR) gene have been associated with myelomagenesis. However, controversial data have been published regarding a protective role of variant alleles of MTHFR on MM.Patients and methods To investigate the influence of two common polymorphisms of MTHFR C677T and A1298C on the risk of multiple myeloma (MM), we performed a matched case-control study. The methylation status pattern of p16 was also addressed.Results The frequency each of 677 CC, 677CT, and 677TT was 31, 44, and 25%, respectively, whereas, the frequency each of 1298 AA, AC, CC was 48, 44, and 8% in MM patients. In the control group, the frequency each of 677CC, 677CT, and 677TT was 36, 45, and 19%, respectively, while the frequency each of 1298 AA, AC, CC was 37, 50, and 13%, respectively. No significant association between susceptibility to MM, 677, and 1298 MTHFR variants was detected. As regards p16 methylation, we confirmed a high prevalence of p16 methylation (40%) in patients affected by MM and demonstrated that MTHFR 677CC is associated with a higher prevalence of p16 hypermethylation.Conclusions Our data demonstrated that variant alleles did not play a key role neither in protection nor in increased risk for MM, suggesting that the effect of MTHFR on folate metabolism might be modified by diet intake. Moreover, our findings demonstrated that p16 hypermethylation might be a frequent genetic aberration in MM and may contribute with other molecular aberrations in the pathogenesis of this malignant disorder.     

Homocysteine and methylenetetrahydrofolate reductase C677T and A1298C polymorphisms in Tunisian patients with severe coronary artery disease

Elevation in homocysteine and methylenetetrahydrofolate reductase (MTHFR) gene variants, C677T and A1298C, have been linked with atherothrombosis. However their exact contribution to coronary artery disease (CAD) remains controversial. Moreover, data from Tunisian patients are scarse. We examined the association of MTHFR C677T and A1298C, and changes in plasma homocysteine in 352 Tunisian patients with angiographically-demonstrated CAD, and 390 age and gender-matched healthy subjects. Significantly higher frequency of 677T allele and homozygous 677T/T genotype were seen in patients vs. control subjects; the distribution of A1298C alleles and genotypes being comparable in the two groups. Specific MTHFR haplotypes comprising 677C/1298A (P < 0.001) and 677T/1298A (P < 0.001) were negatively and positively associated with CAD, respectively. Plasma homocysteine concentration was significantly higher in 677T/T genotype with respect to 677C/C and 677C/T genotypes in patients and controls, but homocysteine levels were generally comparable between both groups. Univariate analysis identified 677T/1298A (P = 0.033) haplotype to be positively associated with CAD, which remained significant by multivariate analysis after adjusting for a number of covariates (P = 0.038). MTHFR C677T, but not A1298C SNPs, is associated with CAD and with elevated homocysteine levels in a Tunisian population. The negative and positive association of the 1298A allele with CAD being indicative of a neutral (absent) effect of the A1298C SNP on disease pathogenesis.     

Identification of six methylenetetrahydrofolate reductase (MTHFR) genotypes resulting from common polymorphisms: impact on plasma homocysteine levels and development of coronary artery disease

Although three common MTHFR polymorphisms (C677T, A1298C, T1317C) have been reported, only polymorphism C677T has been investigated intensively as a risk factor for coronary artery disease (CAD). We investigated polymorphism frequencies, allelic associations and the effect of the resulting MTHFR genotypes on total plasma homocysteine (tHcy) levels and on coronary risk in a case-control study with 1000 angiographically confirmed Middle-European CAD patients and 1000 matched controls. Three out of four theoretically possible MTHFR haplotypes were detected: *1 (677C, 1298A), *2 (677T, 1298A), and *3 (677C, 1298C). The frequencies were *1: 36.4 and 34.4%; *2: 30.8 and 32.3%; and *3: 32.8 and 33.3%, in cases and controls, respectively. Only one patient was heterozygous for 1317C. None of the six resulting genotypes showed significant influence on tHcy levels. Moreover, there was no significant association with CAD risk or with disease severity or early disease manifestation. In the subgroup presenting with acute coronary syndromes, MTHFR genotypes *2/*3 and *3/*3 were surprisingly underrepresented (relative risk of *3/*3, 0.40; 95% confidence interval 0.20-0.79, P=0.009). We conclude from our genotype-based analysis that, in this well-fed Middle-European population, the observed common allelic variants of the MTHFR gene have no significant influence on tHcy levels or on the chronic process of CAD development.     

Polymorphisms of the methylenetetrahydrofolate reductase gene and clinical outcomes in HLA-matched sibling allogeneic hematopoietic stem cell transplantation

To evaluate whether the C677T and A1298C polymorphisms of 5,10-methylenetetrahydrofolate reductase (MTHFR) are related to the toxicity of methotrexate (MTX) used in allogeneic stem cell transplantation, we performed association analysis between these genetic polymorphisms and the clinical outcomes of patients treated using human leukocyte antigen-matched sibling stem cell transplantation. Patients (n=72) with hematological malignancy or aplastic anemia were given a short course of MTX as a graft-versus-host disease prophylaxis. Patients with the 677TT genotype showed higher total bilirubin levels (677TT vs 677CT vs 677CC, 14.5 vs 8.6 vs 3.8 mg/dl, respectively; p=0.07) and higher aspartic transaminase levels (677TT vs 677CT vs 677CC, 678.9 vs 156.6 vs 111.8 IU/l; p=0.04). Platelet recovery to 20,000/μl was slower for patients with the 677TT genotype than for patients with other genotypes (677TT, 59 days; 677CT, 26 days; 677CC, 26 days; p=0.0075). The influences of the C677T polymorphism on treatment-related mortality (TRM) were also analyzed. One-year cumulative TRMs for patients with the TT genotype and the other genotypes were 66 and 30% (p=0.04) and their respective 1-year overall survivals were 30 and 56% (p=0.11). No association was observed between the A1298C polymorphism and clinical outcome for any of the different genotypes. Therefore, patients at high risk of developing hepatic toxicity and with a poor likelihood of survival could be selected by genotyping MTHFR C677T before allogeneic stem cell transplantation.     

A common haplotype on methylenetetrahydrofolate reductase gene modifies the effect of angiotensin-converting enzyme inhibitor on blood pressure in essential hypertension patients--a family-based association study

Our recent study indicated that MTHFR C677T polymorphism may involve in genetic control of blood pressure response to treatment by benazepril, an ACE inhibitor. Currently, we proposed to further investigate whether short-term blood pressure response to benazepril, was modulated by haplotypes re-constructed from both C677T and A1298C polymorphisms in MTHFR gene. A total of 410 hypertensive patients recruited from 344 nuclear families were treated orally with benazepril at a daily dosage of 10 mg for 15 consecutive days. Blood pressures were measured at baseline and on the 16th day of treatment. In addition, 689 family members of these patients were also genotyped. Among these patients, the frequency of MTHFR A1298C AA, AC and CC genotypes was 74.4%, 23.9%, and 1.7%, respectively. The frequency of MTHFR C677T CC, CT and TT genotypes was 23.7%, 51.2%, and 25.1%, respectively. Only three haplotypes, 677T-1298A (50.8%), 677C-1298A (35.7%), and 677C-1298C (13.5%) were re-constructed. Multivariate regression models with generalized estimating equation (GEE) correction detected that the individuals carrying one copy of haplotype 677C-1298C had significantly lower diastolic and systolic blood pressure response (DeltaDBP and DeltaSBP) to benazepril treatment (p= 0.003 and p =0.043, respectively), in comparison to those without haplotype 677C-1298C. The results of family-based association test further confirmed that haplotype 677C-1298C was more frequently transmitted in subjects with either lower residual of DeltaDBP or DeltaSBP. For residual of DeltaDBP, the p-values are 0.007 in an additive model and 0.005 in a dominant model. For residual of DeltaSBP, the p-values are 0.009 in an additive model and 0.006 in a dominant model. Our findings suggest that MTHFR 677C-1298C haplotype modulate blood pressure responsiveness to shortterm treatment of ACE inhibitor in Chinese essential hypertensive patients.     

Methotrexate related adverse effects in patients with rheumatoid arthritis are associated with the A1298C polymorphism of the MTHFR gene

BACKGROUND: There is an association between C677T polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene and methotrexate related toxicity. OBJECTIVE: To examine the relations between the recently described A1298C polymorphism of the MTHFR gene, plasma homocysteine, methotrexate toxicity, and disease activity in patients with rheumatoid arthritis. DESIGN: A cross sectional study on 93 methotrexate treated patients with rheumatoid arthritis, comprising a clinical interview and physical examination to determine disease activity and methotrexate related adverse reactions. Genotype analysis of the MTHFR gene was carried out and fasting plasma homocysteine and serum folate concentrations were measured. The data were analysed using univariate analysis. Allele and genotype distributions were compared with those of a healthy control group. RESULTS: The frequency of the 1298CC genotype (24.7%) in the rheumatoid study group was greater than expected in the general population (12.8%, p<0.001). This genotype was associated with a significantly low rate of methotrexate related side effects. The odds ratio for side effects in patients with wild type 1298AA genotype v 1298CC genotype was 5.24 (95% confidence interval, 1.38 to 20). No correlation of disease activity variables or plasma homocysteine with MTHFR A1298C and C677T polymorphisms was observed. CONCLUSIONS: 1298CC polymorphism was more common in methotrexate treated rheumatoid patients than expected in the population, and was associated with a reduction in methotrexate related adverse effects. The A1298C polymorphism of the MTHFR gene may indicate a need to adjust the dose of methotrexate given to patients with rheumatoid arthritis.     

Polymorphisms in the methylenetetrahydrofolate reductase gene are associated with susceptibility to acute leukemia in adults

Reduction of 5,10-methylenetetrahydrofolate (methyleneTHF), a donor for methylating dUMP to dTMP in DNA synthesis, to 5-methyltetrahydrofolate (methylTHF), the primary methyl donor for methionine synthesis, is catalyzed by 5,10-methylenetetrahydrofolate reductase (MTHFR). A common 677 C --> T polymorphism in the MTHFR gene results in thermolability and reduced MTHFR activity that decreases the pool of methylTHF and increases the pool of methyleneTHF. Recently, another polymorphism in MTHFR (1298 A --> C) has been identified that also results in diminished enzyme activity. We tested whether carriers of these variant alleles are protected from adult acute leukemia. We analyzed DNA from a case-control study in the United Kingdom of 308 adult acute leukemia patients and 491 age- and sex-matched controls. MTHFR variant alleles were determined by a PCR-restriction fragment length polymorphism assay. The MTHFR 677TT genotype was lower among 71 acute lymphocytic leukemia (ALL) cases compared with 114 controls, conferring a 4.3-fold decrease in risk of ALL [odds ratio (OR = 0.23; 95% CI = 0.06-0.81]. We observed a 3-fold reduction in risk of ALL in individuals with the MTHFR 1298AC polymorphism (OR = 0.33; 95% CI = 0.15-0.73) and a 14-fold decreased risk of ALL in those with the MTHFR 1298CC variant allele (OR = 0.07; 95% CI = 0.00-1.77). In acute myeloid leukemia, no significant difference in MTHFR 677 and 1298 genotype frequencies was observed between 237 cases and 377 controls. Individuals with the MTHFR 677TT, 1298AC, and 1298CC genotypes have a decreased risk of adult ALL, but not acute myeloid leukemia, which suggests that folate inadequacy may play a key role in the development of ALL.     

Homocysteine and folate status in methotrexate-treated patients with rheumatoid arthritis

OBJECTIVE: To study (i) the influence of methotrexate (MTX) therapy on homocysteine and folate metabolism in patients with rheumatoid arthritis (RA), (ii) the influence of the C677T mutation in the methylenetetrahydrofolate reductase gene (MTHFR) on the change in plasma homocysteine levels during MTX treatment, and (iii) the interference of folate and homocysteine metabolism with the efficacy and toxicity of treatment with MTX. METHODS: The 113 patients enrolled in this study were participating in a 48-week, multicentre, double-blind, placebo-controlled study comparing the efficacy and toxicity of MTX treatment with and without folic or folinic acid supplementation. The MTX dose was 7.5 mg/week initially and increased to a maximum of 25 mg/week if necessary. Concentrations of total folate, 5-methyl tetrahydrofolate (in serum and in erythrocytes) and of homocysteine, cysteine and cysteine-glycine and the MTHFR genotype were determined before the start of the study, after 6 weeks, and after 48 weeks or on withdrawal from the study. Blood was drawn from fasting patients at a standardized time in the morning, 16 h after intake of MTX. The laboratory results were related to parameters of efficacy and toxicity of MTX treatment. RESULTS: Baseline values were distributed equally in the three treatment groups. The mean plasma homocysteine level (normal range 6-15 micromol/l) before the start of MTX was relatively high in all groups: 15.4 micromol/l [95% confidence interval (CI) 13.5 to 17.2] in the MTX plus placebo group (n=39), 14.3 micromol/l (95% CI 12.2 to 16.4) in the MTX plus folic acid group (n=35) and 15.9 micromol/l (95% CI 13.7 to 18.1) in the MTX plus folinic acid group (n=39). After 48 weeks of MTX therapy, the mean homocysteine level showed an increase in the placebo group (+3.6 micromol/l, 95% CI 1.7 to 5.6). In contrast, a decrease was observed in the groups supplemented with folic or folinic acid (folic acid, -2.7 micromol/l, 95% CI -1.4 to -4.0; folinic acid, -1.6 micromol/l, 95% CI -0.1 to -3.0). The differences in the change in plasma homocysteine level between the placebo group and each of the two folate-supplemented groups were statistically significant (P<0.0001), contrary to the difference between the folic and folinic acid groups (P=0.26). Linear regression analysis showed that the change in plasma homocysteine level was statistically significantly associated with folic or folinic acid supplementation (P=0.0001) but not with the presence or absence of the C677T mutation in the MTHFR gene. Homozygous mutants had a higher plasma homocysteine concentration at baseline. No relationship was found between the change in disease activity and the change in homocysteine concentration or the mean homocysteine concentration after 48 weeks of MTX therapy. Toxicity-related discontinuation of MTX treatment was not associated with the change in homocysteine concentration. CONCLUSIONS: Low-dose MTX treatment in RA patients leads to an increased plasma homocysteine level. Concomitant folate supplementation with either folic or folinic acid decreases the plasma homocysteine level and consequently protects against potential cardiovascular risks. No relationship was found between the change in homocysteine concentration and the presence or absence of the C677T mutation in the MTHFR gene. Homocysteine metabolism was not associated with efficacy or toxicity of MTX treatment.