基因多态性对宜昌地区类风湿关节炎患者甲氨蝶呤疗效的影响

目的 探讨甲基四氢叶酸还原酶(MTHFR)和ATP结合盒转运蛋白1(ABCB1)等位基因在宜昌地区类风湿关节炎(RA)患者中分布情况,及其与甲氨蝶呤(MTX)治疗效果的相关性.方法 收集整理2016年1月-2019年6月宜昌某三甲医院基因检测室进行MTHFR C677T、MTHFR A1298C、ABCB1 C3435...     

MTHFR基因多态性与ALL患儿MTX血药浓度及严重毒副反应的相关性研究

目的:在儿童急性淋巴细胞白血病(ALL)患者中,探讨亚甲基四氢叶酸还原酶(MTHFR C677T和A1298C)基因多态性与甲氨蝶呤(MTX)化疗后44 h血药浓度和严重毒副反应间的相关性.方法:收集77例ALL患儿临床资料,监测MTX输注后44 h的血药浓度并进行MTHFR基因分型;分析MTHFR C677T基因型和...     

Pharmacogenetic relevance of MTHFR polymorphisms

The 5,10-methylenetetrahydrofolate reductase (MTHFR) is a key enzyme for intracellular folate homeostasis and metabolism. Two common MTHFR polymorphisms, C677T and A1298C, which lead to an altered amino acid sequence, have been associated with a decreased enzyme activity and susceptibility to cancer suggesting that these genetic variants may modulate the risk of several malignancies. C667T, and to a lesser extent A1298C polymorphisms, are also reported to influence the cytotoxic effect of fluoropyrimidines and antifolates providing support for their pharmacogenetic role in predicting the efficacy and the toxicity in cancer and rheumatoid arthritis patients. A combined polymorphisms and haplotype analysis may result in a more effective approach than a single polymorphism one. Moreover gene-nutrient/environmental and gene-racial/ethnic interactions have been shown to affect the impact of these MTHFR genetic variants. Further well-designed studies are needed to clarify the role of MTHFR polymorphisms to derive dose adjustment recommendations on the basis of the patient's genotype.     

Genetic polymorphisms in metabolic and cellular transport pathway of methotrexate impact clinical outcome of methotrexate monotherapy in Japanese patients with rheumatoid arthritis

The aim of this study was to investigate the impact of genetic polymorphisms in the metabolic and cellular transport pathway of methotrexate (MTX) on the clinical outcome of MTX monotherapy in Japanese rheumatoid arthritis (RA) patients. Fifty-five patients were treated with MTX monotherapy at a dose of 4-10 mg/week. The total concentration of MTX-polyglutamates (MTX-PGs) was measured at steady-state in red blood cells (RBCs) by high performance liquid chromatography. The genotype at 16 polymorphic sites in 11 genes (ABCB1, ABCG2, ABCC2, RFC1, PCFT, SLCO1B1, MTHFR, GGH, ATIC, MTR, and MTRR) was analyzed. No significant association between the total concentration of MTX-PGs in RBCs and clinical outcome was found. However, patients with the ABCB1 3435TT genotype had a significantly lower mean disease activity score (DAS) 28 than did patients with the ABCB1 3435CC genotype (p = 0.02). Similarly, patients with the ABCB1 2677AA/AT/TT genotypes had a significantly lower mean DAS28 than did patients with the ABCB1 2677GG/GA/GT genotypes (p = 0.04). The patients with the MTHFR 1298AA genotype had a significantly lower mean DAS28 than those with the MTHFR 1298AC/CC genotypes (p = 0.04). In conclusion, the ABCB1 3435C>T, ABCB1 2677G>A/T, and MTHFR 1298A>C polymorphisms influenced the efficacy of MTX monotherapy.     

677C > T and 1298A > C MTHFR polymorphisms affect arechin treatment outcome in rheumatoid arthritis

Despite the availability of several new agents for the treatment of rheumatoid arthritis (RA), arechin (hydroxychloroquine) remains the mainstay because of both cost-effectiveness and experience with its use. However, there is considerable variation in response to this drug, with toxicity limiting treatment in some patients. Methylenetetrahydrofolate reductase (MTHFR) is involved in the folate metabolism and has been shown to be polymorphic what affects the enzyme activity. To examine the association between 677C > T and 1298A > C MTHFR polymorphisms and arechin efficacy in the treatment of RA, a total of 50 RA patients, treated with arechin were analyzed. In univariate regression analysis model, MTHF R 677T allele was associated with significantly higher frequency of remission, whereas 1298C allele carriers showed a tendency to higher remission rate. In univariate regression analysis model, the presence of MTHFR 677T allele was associated with 2.3-fold higher frequency of remission. Multivariate regression analysis taking into the account the combined effect of MTHFR 677T and 1298C alleles revealed that both alleles were independent factors associated with increased frequency of remission. The results of our study suggest that 677T and 1298C alleles are independent factors associated with increased frequency of remission and the evaluation of C677C > T and A1298A> C MTHFR polymorphisms may be a useful tool to predict arechin treatment outcome in RA patients.     

Genetic determinants of methotrexate toxicity in rheumatoid arthritis patients: a study of polymorphisms affecting methotrexate transport and folate metabolism

Objective  Methotrexate (MTX) is a disease-modifying antirheumatic drug used in the treatment of rheumatoid arthritis (RA). Genetic polymorphisms of reduced folate carrier (RFC1 A80G), P-glycoprotein (MDR1 G2677T>A/C and C3435T), 5,10-methylenetetrahydrofolate reductase (MTHFR C677T and A1298C), thymidylate synthase (TS 2R→3R), methionine synthase (MS A2756G) and methionine synthase reductase (MTRR A66G) modify MTX transport and metabolic effects and may influence the treatment response. Methods  A genotyping approach was used to determine the studied polymorphisms in 213 RA patients. Results  We observed that 56 (26.3%) patients discontinued MTX treatment due to poor response and/or toxicity. RFC1 A80G and MDR1 C3435T polymorphisms increased the risk for overall MTX toxicity (P = 0.039, OR = 3.574, 95% CI = 1.065–11.993 and P = 0.032, OR = 7.801, 95% CI = 1.194–50.960 respectively), while MTHFR A1298C polymorphism had a protective effect on overall MTX toxicity (P = 0.027, OR = 0.170, 95% CI = 0.035–0.820). Conclusion  Our results suggest that genetic polymorphisms in the folate metabolic pathway and MTX transporters modify the toxicity but not the efficacy of MTX treatment.     

中国人群亚甲基四氢叶酸还原酶C677T多态性与急性淋巴细胞白血病关系的Meta分析

目的:探讨中国人群亚甲基四氢叶酸还原酶基因(MTHFR)C677T位点多态性与急性淋巴细胞白血病(ALL)易感性和甲氨蝶呤(MTX)化疗时毒副反应的关系。方法:检索以中国人群为研究对象ALL组和对照组MTHFR基因C677T位点多态性的OR值或RR值为效应指标的相关文献,符合入选标准的文献,应用RevMan 5.0软件对研究结果进行异质性检验和效应值合并,并进行敏感性分析和偏倚评估。结果:纳入MTHFR基因C677T位点多态性与ALL的文献共7篇,共计病例824例,对照1090例。TT+CT vs CC:固定效应模型OR=0.76,95%CI:0.63～0.91;随机效应模型OR=0.70,95%CI:0.52～0.93,TT vs CC+CT:固定效应模型OR=0.90,95%CI:0.70～1.15;随机效应模型OR=0.93,95%CI:0.53～1.61,漏斗图基本对称。MTHFR基因C677T位点多态性与MTX的毒副反应的文献共3篇,共计病例138例。TT+CT vsCC:固定效应模型OR=2.65,95%CI:1.28～5.49;随机效应模型OR=2.96,95%CI:0.66～13.32,TT vsCC+CT:固定效应模型OR=2.68,95%CI:1.14～6.29;随机效应模型OR=3.31,95%CI:0.57～19.21。结论:MTHFR基因677C→T突变对ALL的发生起着保护作用。MTHFR基因TT基因型与ALL的发生无显著的相关性。MTHFR基因多态性与MTX治疗的毒副反应无显著的相关性。更可靠的结论尚需大样本进行进一步研究。     

Methylenetetrahydrofolate reductase and reduced folate carrier-1 genotypes and methotrexate serum concentrations in patients with rheumatoid arthritis

We investigated the genotypes of methylenetetrahydrofolate reductase (MTHFR) and reduced folate carrier-1 (RFC-1), and the serum concentrations of methotrexate (MTX) in 100 outpatients with rheumatoid arthritis (RA). Frequencies of MTHFR C677T and A1298C were similar to those reported in Japanese RA patients, while frequencies of RFC-1 G80A genotypes differed from those reported in RA patients in the United States. No correlations were found between these genotypes and serum MTX levels.     

MTHFR基因1298、677位点多态性与急性淋巴细胞白血病患儿甲氨蝶呤化疗毒副反应的相关性探讨

的：探讨亚甲基四氢叶酸还原酶（MTHFR）基因1298以及677位点多态性与急性淋巴细胞白血病（ALL）患儿甲氨蝶呤（MTX）化疗毒副反应的相关性。方法：分析2014年7月至2017年10月在我院就诊的98例ALL患儿应用MTX化疗和恢复期的临床资料,比较677位点和1298位点基因突变后的不同基因型个体,在高剂量MTX化疗后的代谢水平以及毒副反应。结果：MTHFR C677T突变基因个体对比野生型的基因个体更易发生胃肠道反应,A1298C突变基因个体对比野生型的基因个体更易发生口腔黏膜损害; MTHFR基因的A1298C突变基因个体骨髓抑制的风险低于野生型的基因个体;A1298C突变基因携带个体延长了MTX代谢时间。结论：本研究为急性淋巴白血病患者化疗提供了筛查指标,从而在化疗周期中降低患儿黏膜毒副反应。在基因诊断和化验时提供个体样本筛查指标,从而订制更为有效的治疗方案。     

亚甲基四氢叶酸还原酶C677T与A1298C基因多态性在卡培他滨治疗中晚期结直肠癌患者的临床意义

目的 探讨亚甲基四氢叶酸还原酶（MTHFR）C677T与A1298C基因多态性在卡培他滨治疗中晚期结直肠癌（CRC）患者的安全性及有效性,为临床诊治CRC提供理论依据。方法 收集经病理诊断确诊的中晚期结直肠癌患者50例,用实时荧光定量PCR仪进行MTHFR C677T与A1298C基因多态性检测,观察不同基因型之间安全性及有效性的差异。结果 MTHFR C677T的CC、CT、TT基因型频率分别为46%、40%、14%,TT基因型恶心呕吐的发生率及有效率高于CC与CT基因型,差别具有统计学意义（P<0.05）。MTHFR A1298C的AA、AC、CC基因型频率分别为60%、34%、6%,CC基因型腹泻发生率高于AA与AC基因型,差别具有统计学意义（P<0.05）,MTHFR A1298 C中各基因型有效率差异无统计学意义。结论 MTHFR C677T与MTHFR A1298C基因多态性在卡培他滨治疗CRC患者具有较好的临床意义,但MTHFR A1298C与药物治疗有效率无关。     

GSTP1 and MTHFR polymorphisms are related with toxicity in breast cancer adjuvant anthracycline-based treatment

We have analyzed several members of drug-metabolizing enzymes (DMEs) and other polymorphisms in genes implicated in tumor aggressivity regarding possible links between specific genetic variability in systemic drug bioavailability and toxicity in breast cancer patients treated with adjuvant anthracycline-based treatment. PCR-RFLP and sequencing analyses technique were used for evaluating fourteen previously identified polymorphisms in 94 patients. GSTP1A>G and MTHFR 1298A>C genotypes remained as significant predictors in a multivariate logistic regression analysis. GSTP1 polymorphism was linked to haematological GIII-IV toxicity (P = 0.044, HR= 6.4, 95% CI = 1.05 to 39. Increased and significant HR was obtained for MTHFR-1298 AC+CC group when non-haematological toxicities GIII-IV toxicities were evaluated (HR = 24; 95% CI = 2.3 to 254), P = 0.008. Our results suggest that GSTP1 and MTHFR genotypes may be consider relevant and independent factors of toxicity in adjuvant anthracycline-based treatment of breast cancer.     

Methylenetetrahydrofolate reductase gene polymorphisms and response to fluorouracil-based treatment in advanced colorectal cancer patients

Methylenetetrahydrofolate reductase (MTHFR) controls intracellular CH2FH4 concentrations (required for optimal fluoropyrimidine efficacy) by irreversibly converting CH2FH4 into 5-methyltetrahydrofolate. MTHFR 677C>T and 1298A>C polymorphisms are linked to altered enzyme activity. Thus, mutated MTHFR tumours should, in theory, be more sensitive to 5-fluorouracil (5FU) than wild-type tumours. MTHFR polymorphisms in position 677 and 1298 were analysed in 98 colorectal cancer patients with unresectable liver metastases (57 men, 41 women, mean age 64 years) receiving 5FU-folinic acid. 677C>T and 1298A>C genotypes were determined simultaneously by melting curve analyses on liver metastases. 677C>T genotype distribution was 46.9% wt/wt, 34.7% wt/mut and 18.4% mut/mut; that of 1298A>C was 52.0% wt/wt, 35.7% wt/mut and 12.3% mut/mut. The response rate was not related to 1298A>C genotype but was significantly linked to 677C>T genotype (response rate: 40%, 21% and 56% in wt/wt, wt/mut and mut/mut, respectively; P = 0.040), with an increased response rate in mut/mut tumours relative to wt/wt (odds ratio = 1.88). Thymidylate synthase activity measured in metastases was a significant predictor of 5FU responsiveness and the addition of the 677C>T genotype improved model prediction. MTHFR 1298A>C polymorphism was significantly linked to specific survival, with homozygous mutated patients having the worst prognosis (P = 0.009, relative risk = 2.48 in mut/mut versus wt/wt). MTHFR 1298A>C genotype remained a significant predictor in a multivariate analysis including metastasis characteristics. The results suggest that MTHFR genotypes are relevant and independent factors of patient outcome in 5FU-based treatment of advanced colorectal cancer.     

叶酸代谢相关基因多态性与男性精子异常的相关性研究 #br#

摘要：目的 探讨男性 5,10-亚甲基四氢叶酸还原酶（MTHFR）基因和甲硫氨酸合成酶还原酶（MTRR）基因与精 子异常及不良孕产发生的相关性。方法 选择 2017年 1月—12月就诊于甘肃省妇幼保健院男科的汉族男性 929例, 其中患有精子异常症者（精子异常组）290例,妻子有不明原因不良孕产史者（不良孕产组）198例和有健康生育史者 （对照组）441例,所有入组者进行 MTHFR C677T、A1298C和 MTRR A66G位点的多态性检测,探讨其与精子异常和不 良孕产的相关性。结果 精子异常组和不良孕产组的 MTHFR C677T TT和 MTRR A66G AG、GG基因型频率均高于 对照组（P＜0.05）;不良孕产组的 MTHFR A1298C CC基因型频率高于对照组（P＜0.05）。多元 Logistic回归分析结果 显示,MTHFR C677T TT 和 MTRR A66G AG、GG 基因型是导致精子异常发生的独立危险因素（P＜0.05）;MTHFR C677T TT、MTHFR A1298 CC和 MTRR A66G AG、GG基因型是导致不良孕产发生的独立危险因素（P＜0.05）。结论 MTHFR C677T和 MTRR A66G位点的基因多态性分布与男性精子异常及不良孕产的发生有相关性,MTHFR C677T TT和 MTRR A66G AG、GG可能是精子异常及不良孕产发生的独立危险因素。     

Linkage disequilibrium between the 677C>T and 1298A>C polymorphisms in human methylenetetrahydrofolate reductase gene and their contributions to risk of colorectal cancer

A common polymorphism in a folate-metabolizing gene, methylenetetrahydrofolate reductase (MTHFR) 677C>T has been associated with reduced risk of colorectal cancer. In this study, we investigated whether a second common polymorphism of the gene, MTHFR 1298A>C, is an independent risk factor for colorectal cancer and if it is associated with plasma folate and total homocysteine (tHcy) levels. We also examined whether the 677C>T and 1298A>C polymorphisms are in linkage disequilibrium and whether combined heterozygosity confers additional (or reduced) risk of colorectal cancer. We conducted a nested case-control study of 211 incident colorectal cancer cases and 343 controls in the prospective Physicians' Health Study. The MTHFR 677C>T and 1298A>C polymorphisms were in linkage disequilibrium in this population. Compared to MTHFR 1298AA genotype, multivariate-adjusted relative risk of colorectal cancer was 0.73 (95% CI 0.37-1.43) for the MTHFR 1298CC genotype. The slight reduction in risk was not a result of its linkage disequilibrium with the 677C>T polymorphism. This polymorphism was not significantly correlated with the plasma folate and tHcy levels. The combined heterozygosity did not modify the cancer risk; nor did it change the plasma folate and tHcy significantly. We conclude that the MTHFR 1298A>C polymorphism is a less substantial independent risk factor for colorectal cancer compared to the 677C>T polymorphism.     

MTHFR基因多态性与下肢DVT的相关性研究

目的探讨N5,N10-亚甲基四氢叶酸还原酶(Methylenetetrahydrofolatereductase,MTHFR)基因多态性与我国东北地区人群下肢深静脉血栓形成(Deepvenousthrombosis,DVT)的关系。方法采用PCR-RFLP检测73例DVT患者和109名健康对照者MTHFRC677T、A1298C突变,计算患者组与对照组的基因型频率、等位基因频率以及突变与DVT的相关性。结果患者组677TT、677CT基因型频率和T等位基因频率分别为38.4%、49.3%和63%,明显高于对照组(分别为15.6%、46.8%和39%。χ2=19.393,P<0.01;χ2=20.200,P<0.01)。677TT和677CT基因型的个体比677CC基因型的个体发生DVT的相对危险分别约高7或3倍(ORTT=7.503,95%可信区间为2.931～19.207;ORTC=3.215,95%CI为1.391～7.434)。患者组与对照组MTHFR1298各基因型和等位基因分布无显著性差异(χ2=3.533,P>0.05;χ2=0.100,P>0.05),但1298CC677CC基因型的个体比1298AA、677CC基因型的个体发生DVT的相对危险约高16倍(OR=16.500,95%CI为1.353～201.290)。结论MTHFR基因C677T和A1298C突变可能为我国东北地区人群下肢DVT的危险因素。     

Polymorphisms in catechol-O-methyltransferase and methylenetetrahydrofolate reductase in relation to the risk of schizophrenia.

BACKGROUND: Evidence is emerging for the association of aberrant homocysteine-methylation cycle and increased risk of schizophrenia. METHODS: We examined the prevalence of the catechol-O-methyltransferase (COMT) 324G>A (Val108/158Met) and methylenetetrahydrofolate reductase (MTHFR) 677C>T polymorphisms in 252 patients with schizophrenia and 405 control subjects. All subjects were of Dutch ancestry. RESULTS: The COMT 324AA genotype was not associated with an increased risk of schizophrenia (odds ratio (OR)=1.38 [95% CI: 0.88-2.16], P=0.162), and the MTHFR 677TT genotype showed a nearly significant increased risk for schizophrenia (OR=1.65 [95% CI: 0.97-2.82], P=0.067). The odds ratio for schizophrenia associated with joint occurrence of the COMT 324AA and MTHFR 677TT genotype was 3.08 (95% CI: 1.08-8.76) (P=0.035). Increasing number of low enzyme activity alleles in the COMT and MTHFR genotype combinations were associated with an increased risk of schizophrenia (test for trend, P=0.017). CONCLUSIONS: Our findings do not support a major role for the COMT 324AA and MTHFR 677TT genotype alone, but the combination of both genotypes might increase schizophrenia susceptibility.     

MTHFR 677位基因多态性与大剂量MTX联合甲酰四氢叶酸钙治疗骨肉瘤关系的临床研究

目的研究骨肉瘤患者人群中MTHFR677的基因突变的频率分布,比较MTHFR677位基因突变与大剂量MTX联合甲酰四氢叶酸钙治疗骨肉瘤的临床疗效以及毒副反应的发生率的关系。方法选取我院住院治疗的骨肉瘤患者210例,采用RT-PCR方法检测分析MTHFR677位点基因突变在骨肉瘤中的分布频率,同时分析不同MTHFR677基因型患者的临床疗效与毒副反应。结果210例患者中,MTHFR677位CC野生型患者115例,频率为54．8％;677位CT型患者63例。突变频率为30％;677位TT型患者32例,突变频率为15．2％。MTHFR677位基因型不同的三组患者,肿瘤细胞坏死率差异无统计学意义（P〉0．05）。5年无瘤生存率差异无统计学意义（P〉0．05）。MTHFR677位发生CT或TT突变的患者,血尿发生比例明显升高,差异有统计学意义（P〈0．05）。结论大剂量的MTX联合甲酰四氢叶酸钙治疗骨肉瘤患者,不同MTHFR677位基因型患者出现肾毒副反应发生率有差异,尤其是MTFHR677位发生突变的患者出现肾脏毒副反应的发生率高于野生型。     

Interactions between the single nucleotide polymorphisms in the homocysteine pathway (MTHFR 677C>T, MTHFR 1298 A>C, and CBSins) and the efficacy of HMG-CoA reductase inhibitors in preventing cardiovascular disease in high-risk patients of hypertension: the GenHAT study

BACKGROUND: High homocysteine blood concentrations predispose to coronary artery disease and statins influence homocysteine levels. AIM: To study whether genes that regulate homocysteine metabolism interact with statins to modify the risk of coronary heart disease (CHD) and other cardiovascular outcomes. METHODS: The Genetics of Hypertension Associated Treatment is an ancillary study of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT). The genotyped population in the Lipid-Lowering Trial of Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial included 9624 participants randomly assigned to pravastatin or to usual care. The efficacy of pravastatin in reducing risk of all-cause mortality and CHD was compared among genotype strata (MTHFR 677 CC, CT, and TT, MTHFR 1298 AA, AC, and CC, CBSins DD and I) by examining an interaction term in a proportional hazards model. RESULTS: No evidence existed of a pharmacogenetic effect on statins with the MTHFR 1298 A>C genotype for CHD risk. However, in persons with the CC variant for the MTHFR 677 C>T genotype, a significantly protective effect against CHD [0.71 (95% CI 0.58-0.87)] was shown, although in the CT [1.25 (95% CI 0.97-1.61)] and TT groups [0.80 (95% CI 0.50-1.28)] there were no such effects (interaction hazard ratio P=0.004). The CBSins, I+ variant was associated with a significantly reduced risk for CHD among those on statin treatment [0.58 (95% CI 0.44-0.78)] whereas the DD genotype showed no effect of statin therapy [1.01 (95% CI 0.84-1.20; P=0.002 for interaction]. For the endpoint all-cause mortality, no significant differences in efficacy were noted. CONCLUSION: Polymorphisms in genes in the homocysteine pathway (MTHFR 677 C>T and CBSins) appear to modify the efficacy of pravastatin in reducing risk of cardiovascular events.     

类风湿关节炎患者转运蛋白基因多态性与甲氨蝶呤疗效及不良反应的相关性研究

目的探讨类风湿关节炎（RA）患者还原型叶酸载体（RFC-1）基因G80A及三磷酸腺苷结合盒转运体B1（ABCB1）基因C3435T单核苷酸多态性（SNP）与甲氨蝶呤（MTX）疗效与不良反应的相关性。方法采用实时荧光定量聚合酶链反应（FQ-PCR）法检测136例单用MTX的RA患者RFC-1基因G80A及ABCB1基因C3435T多态性,并与MTX治疗疗效和不良反应相关分析。结果 RFC-1基因G80A及ABCB1基因C3435T多态性与MTX治疗RA的不良反应无明显相关性（P〉0.05）;RFC-1基因G80A多态性与MTX治疗RA的疗效无明显相关（P〉0.05）,而ABCB1基因C3435T的多态性与疗效相关,携带有CC基因型的患者MTX疗效明显优于携带有TT或CT基因型的患者。CT和CC比较,（P=0.015,OR=4.189,95%CI为1.314~13.353）;TT和CC比较,（P=0.02,OR=5.941,95%CI为1.320~26.739）。结论 ABCB1基因C3435T多态性可能对RA患者应用MTX的疗效有预测作用。     

Exploratory analysis of four polymorphisms in human GGH and FPGS genes and their effect in methotrexate-treated rheumatoid arthritis patients

The enzyme folylpoly-gamma-glutamase synthethase (FPGS) plays an important role in the intracellular polyglutamation of the disease-modifying antirheumatic drug methotrexate (MTX) and the length of the polyglutamated MTX product correlates with the time that MTX resides in the cell. The glutamates are released from MTX by activity of the enzyme gamma-glutamyl-hydrolase (GGH), thereby allowing the efflux of MTX. GGH 452C>T has been associated with decreased catalytic activity and higher accumulation of long-chain MTX-polyglutamate. However, single nucleotide polymorphisms (SNPs) in FPGS and GGH genes have not yet been explored for association with MTX efficacy or toxicity. We selected for SNPs with frequencies higher than 10% or, in case of FPGS 114G>A, causing an amino acid change with no known frequencies. In this study, frequencies of two SNPs in FPGS (1994A>G and 114G>A, rs10106 and rs10760502, respectively) and GGH genes (452C>T and 16T>C, rs11545078 and rs1800909, respectively), were determined using a newly developed method in rheumatoid arthritis patients (n = 352) and in a group of healthy controls (n = 360). Next, the SNPs were associated with response to MTX in rheumatoid arthritis patients treated with MTX monotherapy. In rheumatoid arthritis patients, allele frequencies of FPGS 1994A>G were 0.534 (A) and 0.466 (G), and for FPGS 114G>A 0.714 (G) and 0.286 (A). Allele frequencies of GGH 16T>C were 0.737 (T) and 0.263 (C) and for GGH 452C>T 0.912 (C) and 0.088 (T). No significant differences in allele frequencies between rheumatoid arthritis patients and healthy controls were found. In addition, the SNPs were not associated with good clinical response to MTX. Only patients with the GGH 16C-allele and one or no copies of the GGH 452C-16T haplotype were associated with good clinical improvement at 3 months upon treatment with MTX. No associations with efficacy at 6 months and MTX-induced toxicity were found. Therefore we conclude that despite the positive association of the GGH 16C-allele and one or no copies of the GGH 452C-16T haplotype with good clinical improvement at 3 months upon treatment with MTX, the tested SNPs in GGH and FPGS genes are suggested not to be clinically important for MTX treatment outcome.