Serum homocysteine and folate levels in korean schizophrenic patients

Objective

This study was conducted to confirm the results of the authors'' previous research on schizophrenia manifesting high serum homocysteine and low folate levels. This study is anchored on a theory that a high serum homocysteine concentration affects schizophrenia by virtue of a neurotoxic mechanism, and on a report that some schizophrenia patients with high homocysteine levels benefited from high folate ingestion.

Methods

The serum homocysteine, folate, and vitamin B₁₂ levels of 236 normal-control-group subjects and 234 schizophrenia subjects who met the diagnostic criteria based on DSM-IV-TR were compared. The homocysteine levels were measured via fluorescence polarization immunoassay, and the folate and vitamin B₁₂ levels were determined via radioimmunoassay.

Results

The homocysteine levels of the patient group were significantly higher than those of the normal control group. The homocysteine level was more negatively correlated with the folate level in the schizophrenia group than in the control group. The percentages of female and male schizophrenia subjects manifesting high homocysteine levels were 33.8 and 51.5%, respectively. The percentage of schizophrenia subjects with low folate levels was 66.2%. In the low- and normal-folate-level groups, the patient group showed significantly higher homocysteine levels than the normal control group. The low-folate-level patient group particularly showed significantly higher homocysteine levels than the low-folate-level normal control group.

Conclusion

Some schizophrenia patients with high serum homocysteine levels may have the genetic defect of having low folate serum levels. In such cases, folate ingestion may be a good management modality for clinical improvement.     

C677T polymorphism of methylenetetrahydrofolate reductase gene affects plasma homocysteine level and is a genetic factor of late-onset Alzheimer's disease

Background: Elevated plasma homocysteine levels are known as a risk for atherosclerotic vascular disease and venous thrombosis and have been shown as a risk for late‐onset Alzheimer's disease (LOAD). Method: To examine the effect of genetic factors predisposing to elevated plasma homocysteine levels on the occurrence of LOAD, we determined the genotype of a C677T polymorphism of methylenetetrahydrofolate reductase (MTHFR) gene and a variable number tandem repeat (VNTR) spanning exon 13–intron 13 boundary of cystathionine β‐synthase (CBS) gene in patients with LOAD and community‐based control subjects. Results: Logistic regression indicated that the MTHFR‐T allele was a risk for LOAD (P < 0.05), independently from apolipoprotein E‐?4 (APOE‐?4) allele. Kaplan–Meier tests showed that in APOE‐?4 non‐carriers, individuals with the MTHFR‐TT genotype have occurences of LOAD earlier than those with the MTHFR‐CC genotype (P < 0.05). Multiple regression analysis indicates that MTHFR‐T allele increases plasma homocysteine levels (P = 0.0002), while the number of X chromosomes decreases (P = 0.01). Plasma homocysteine level was not correlated with age, plasma albumin reflecting nutritional condition, and the dose of APOE‐?4 allele. The CBS‐20 VNTR allele showed the same trend to increase plasma homocysteine level as the MTHFR‐T allele, but a risk effect for LOAD was not evident. Conclusion: A genetic propensity for elevated plasma homocysteine levels, explained by the MTHFR‐T allele encoding defective enzymatic function, is involved in the development of LOAD, particularly in APOE‐?4 non‐carriers, and that homocysteine metabolism could be a preventive target to LOAD in the elderly.     

The A677V methylenetetrahydrofolate reductase gene polymorphism and carotid atherosclerosis.

BACKGROUND AND PURPOSE: The alanine/valine (A/V) polymorphism at codon 677 of the 5,10 methylenetetrahydrofolate reductase (MTHFR) gene correlates with elevated levels of plasma homocysteine and with an increased risk of atherosclerotic cardiovascular disease. Our study was designed to assess the frequency of the A and V alleles in patients with asymptomatic severe carotid artery stenosis (CAS) assessed by extracranial duplex examination in comparison with age- and sex-matched subjects without carotid atherosclerosis. METHODS: Consecutive patients (n=48; 28 men, mean+/-SD age 67.1+/-11. 4 years) with asymptomatic severe (>75%) CAS were compared with subjects without CAS (n=26; 15 men, aged 61.2+/-11.5). The MTHFR genotype was analyzed by polymerase chain reaction followed by HinfI digestion. The chi(2) analysis and t test were used to compare the groups. RESULTS: The frequency of V alleles was significantly higher in the CAS group (0.47) compared with control subjects (0.27, chi(2) test; OR 2.4 [95% CI 1.1 to 5.3]; P<0.02). CONCLUSIONS: Our results indicate that the MTHFR A677V allele is significantly associated with severe CAS.     

Association of methylenetetrahydrofolate reductase A1298C polymorphism but not of C677T with multiple sclerosis in Tunisian patients

Background and objective

Multiple sclerosis (MS) is a chronic neurological disease characterized by central nervous system (CNS) inflammation and demyelination of nerve axons. The aim of this study was to investigate a possible association between the methylenetetrahydrofolate reductase (MTHFR) gene and multiple sclerosis in Tunisian patients.

Patients and methods

The genotyping of two missense variants of the methylenetetrahydrofolate reductase (MTHFR) gene, C677T and A1298C was performed in 80 multiple sclerosis patients and 200 healthy controls.

Results

No significant differences were found in the frequency of the MTHFR C677T polymorphism between MS patients and healthy controls. However, the genotype prevalence of the missense variant MTHFR A1298C was significantly different between patients and controls (A/C: 55% versus 7%, p < 10⁻³; C/C: 13.75% versus 0%, p < 10⁻³, respectively).

Conclusion

Although our preliminary findings suggest no association between the MTHFR C677T variants and MS, there is evidence to suggest a significant association between the MTHFR A1298C polymorphisms and MS.     

Distribution of 1298A>C polymorphism of methylenetetrahydrofolate reductase gene in patients with bipolar disorder and schizophrenia.

We investigated the genotype frequency of methylenetetrahydrofolate reductase (MTHFR) 1298A>C polymorphism in the group of patients with bipolar disorder type I (BDI) (n=200) and schizophrenia (n=200) and in the control group (n=300). Odds ratio (OR) for patients with BD and schizophrenia in 1298CC homozygous state was 3.768 (95% CI=1.752-8.104); P=0.0003; (P=0.0006 after Bonferroni correction) and 2.694; (95% CI=1.207-6.013); P=0.0123 (P=0.0246 after Bonferroni correction), respectively. The stratification of patients based on gender revealed significant association of 1298CC genotype with female patients only with BDI (OR=7.293; 95% CI=2.017-26.363; P=0.0005). Our results confirm association of BD and schizophrenia with the 1p36.3 MTHFR locus and with the methyl group transfer using folate-dependent one-carbon pathway.     

Association of the C677T and A1298C polymorphisms in the 5,10 methylenetetrahydrofolate reductase gene in patients with migraine risk

Although controversial, diminished activity of 5,10 methylenetetrahydrofolate reductase (MTHFR), a regulatory enzyme of homocysteine metabolism, may predispose to migraine in Turkish people. In a case-control study, we determined the prevalence of two common MTHFR polymorphisms,C677T and A1298C, in 102 migraine patients (23 migraine with aura, 70 migraine without aura and nine with tension-type headache) and compared it to that of 136 healthy controls. The frequencies of the T allele of MTHFR677 and the C allele of MTHFR1298 were significantly higher in the total migraine population (33.82%, 33.82%) than in controls (25.38% and 24.26%), respectively.The genotypes T677T and C1298C were the only genotypes significantly associated with migraine (OR=5.702; 95% CI=1.184-27.457; P=0.015) and (OR=8.933; 95% CI=1.953-40.869; P=0.001), respectively). Individuals with migraine with aura with C1298C and C677C/C1298C genotypes were even more profoundly associated with migraine risk than others (OR=14.105; 95% CI=2.417-82.320; P=0.0001) and (OR=10.050; 95% CI=1.580-63.907; P=0.003), respectively. However individuals with migraine without aura with T677T and C1298C genotypes showed the same susceptibility (OR=7.444; 95% CI=1.503-36.863); P=0.005). Patients with C1298C and C677C/C1298C genotypes may also predispose to tension-type headache (OR=8.375; 95% CI=0.685-102.458); P=0.049).     

Effect of the methylenetetrahydrofolate reductase gene polymorphisms on homocysteine, folate and vitamin B12 in patients with bipolar disorder and relatives

We investigated the effect of polymorphic variants of c.1298A>C (Glu429Ala) and c.677C>T (Ala222Val) in methylenetetrahydrofolate (MTHFR) gene on the total homocysteine (tHcy), folate and B12 levels in patients with bipolar disorder, first-degree relatives of patients, and controls. The c.677C>T and c.1298A>C polymorphisms in MTHFR were determined by polymerase chain reaction-restriction fragment length polymorphism in 197 bipolar patients, 278 relatives and 238 controls. tHcy and folate and vitamin B12 levels were measured by Fluorescence Polarization Immunoassay and Electrochemiluminescence, respectively. The tHcy was significantly increased in patients and relatives. In contrast, folate and B12 were significantly lower in patients and relatives. Gender was not considered as a significant determinant in the multivariate analysis. Genotypes of c.1298A>C and c.677C>T were correlated with tHcy, folate and B12. Patients and relatives carrying TT and/or AA and AC genotypes had elevated tHcy and reduced folate and B12 levels. High tHcy but low folate and vitamin B12 levels may be a risk factor for development of bipolar disorder.     

Association of the C677T and A1298C polymorphisms of methylenetetrahydrofolate reductase gene in patients with essential tremor in Turkey.

Essential tremor (ET) is a most common human movement disorder of unknown etiology. Previous reports have shown that the C677T polymorphism of methylenetetrahydrofolate reductase gene has been associated with neurodegenerative disorders. To investigate the role of methylenetetrahydrofolate reductase gene polymorphisms in essential tremor, we analyzed the alleles and genotypes of methylenetetrahydrofolate reductase (MTHFR) C677T and MTHFR A1298C in a total of 158 unrelated essential tremor patients and compared them with those of 246 unrelated healthy control subjects, using a polymerase chain reaction restriction fragment length polymorphism method. The allele frequency of MTHFR 677T was 35.76% in the essential tremor cases and 30.08% in the controls. We obtained statistically significant results for MTHFR677 and also for MTHFR1298. The MTHFR T677T genotype was overrepresented and was statistically significant. The T677T/A1298A and C677C/C1298C compound genotypes were similarly statistically significant. The C677C/A1298A compound genotype provided protection for essential tremor. In conclusion, the MTHFR 677T, 1298C alleles and MTHFR T677T genotype and T677T/A1298A, and C677C/C1298C compound genotypes are genetic risk factors for essential tremor in Turkey.     

The roles of methylenetetrahydrofolate reductase 677C>T and 1298A>C polymorphisms in moyamoya disease patients

Purpose

The methylenetetrahydrofolate reductase (MTHFR) 677C>T and 1298A>C polymorphisms, which are associated with hyperhomocysteinemia and nitric oxide (NO) deficiency (which is related to atherothrombosis and cerebral ischemia), have not been studied in moyamoya disease. A case-control study was performed to investigate whether the MTHFR 677C>T and 1298A>C polymorphisms contribute to moyamoya disease (MMD).

Methods

One hundred and seven Korean patients with MMD (mean age, 20.85?±?15.89 years; 66.4 % female) and 232 healthy control subjects (mean age, 23.99?±?16.16 years; 56.8 % female) were included. Genotyping for the MTHFR 677C>T and 1298A>C polymorphisms and measurements of homocysteine, folate, vitamin B₁₂, and NO in the cerebrospinal fluid (CSF) were performed. The statistical analysis was performed by multivariate linear regression and logistic regression.

Result

The MTHFR 677CT+TT genotype frequency was significantly increased with early-onset MMD (<10 years) compared with late-onset MMD (≥10 years) (adjusted odds ratio, 3.392; 95 % confidence interval, 1.294–8.893, P?=?0.013). The MTHFR 677C-1298C/677T-1298A diplotype (1.71?±?1.23 arbitrary units) presented significantly lower NO levels in the CSF compared with the 677C-1298A/677C-1298A diplotype (11.40?±?12.24 arbitrary units).

Conclusion

The MTHFR 677C>T and 1298A>C polymorphisms have restricted roles in the Korean MMD population. Therefore, further studies involving larger and more heterogeneous cohorts are needed to extend our understanding of the influence of polymorphisms in MTHFR and other thrombophilic genes on MMD.     

亚甲基四氢叶酸还原酶基因C677T多态性与先兆型偏头痛相关性的Meta分析

目的探讨亚甲基四氢叶酸还原酶(MTHFR)基因C677T多态性与先兆型偏头痛(MA)的相关性。方法检索1994年1月~2013年3月MEDLINE、EBSCO、EMBASE数据库及PubMed,以及中国医院知识仓库中文期刊全文库、中国生物医学文献数据库、维普、万方等中文数据库中关于MTHFR基因C677T多态性与MA相关性的文献,按纳入、排除标准选择文献,并采用RevMan 5软件进行Meta分析。结果共纳入18项病例对照研究,其中MA患者4276例,对照者27979例。各研究间具有很强的异质性(P0.05,I2=72%),采用随机效应模型分析。Meta分析显示,MTHFR基因TT基因型发生MA的风险明显高于CT+CC基因型(OR=1.33,95%CI:1.02~1.75,P0.01)。剔除不符合H-W遗传平衡定律的3篇文献后,总的分析结果依然稳定(OR=1.39,95%CI:1.02~1.88,P0.01)。在MA人群中所做种族分层分析结果显示,在地中海人种TT基因型增加了MA的发病风险,而在其他高加索人(包括北欧人种和印度雅利安人种)、芬兰人、土耳其人及日本人的研究并未显示出这种相关性。结论 MTHFR基因C677T多态性与MA相关,其TT基因型个体MA发病的风险增加。这在不同种族间存在一定差别。     

Plasma homocysteine and the methylenetetrahydrofolate reductase C677T gene variant: lack of association with schizophrenia.

Disturbances in methyl-carbon metabolism, which result in hyperhomocysteinemia, have been associated with schizophrenia. Homozygosity for the T677 allele of the methylenetetrahydrofolate reductase (MTHFR) gene, which encodes for a thermolabile enzyme associated with hyperhomocysteinemia, has been found to be increased in schizophrenic patients. We have investigated whether plasma homocysteine concentration and the frequency of C677T MTHFR variant were increased in schizophrenic inpatients of a psychiatric hospital (n=210) compared with controls (n=218). There were no significant differences in plasma homocysteine concentrations between the schizophrenia and the control group. The distributions of T allele and TT genotype frequencies were similar in both groups (40% and 15%). These results show that impaired homocysteine metabolism is unlikely in schizophrenia.     

A methylenetetrahydrofolate reductase gene polymorphism in multiple sclerosis

There have been several indications that cellular methylation pathways might be affected in multiple sclerosis (MS). We have investigated 150 MS patients for a biallelic polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene, since the less frequent of these alleles is functionally relevant and is associated with reduced enzymatic function. However, the distribution of alleles and genotypes was found to be close to identical in MS patients and healthy controls, regardless of subgroup analysis after clinical form or HLA class II phenotype. We conclude that this polymorphism does not influence susceptibility to MS.     

Effect of methylenetetrahydrofolate reductase 677 C-T, 1298 A-C, and 1317 T-C on factor V 1691 mutation in Turkish deep vein thrombosis patients

Possible effect of three common mutations in (MTHFR 677 C-T; 1317 T-C; 1298 C-A) and FV 1691 G-A mutation was studied in Turkish patients with thrombosis and compared with normal controls. The case-control study included 68 patients with the diagnosis of deep vein thrombosis and 66 controls, consecutively selected among subjects without personal and familial history of atherothrombosis. Patients with deep vein thrombosis were selected if Doppler ultrasonography was positive. Only, the comparison of factor V 1691 G-A mutation revealed statistically significant difference in control (6.06%) and deep vein thrombosis (23.5%) group. Risk assessment of double prothrombotic gene alterations revealed only FV 1691 G-A mutation as an independent risk factor for thrombosis (odds ratio 4.7 [1.5-15.0]), but our data suggested that MTHFR 677 has effect on its own (odds ratio 1.97 [0.6-2.7]) but may have synergy with FV 1691 G-A (odds ratio 8.12 [2.0-25.3]). However, MTHFR 1298 A-C and 1317 T-C does not have any effect; furthermore, being heterozygote at two different loci or homozygosity at least in a locus for 677 and 1298 revealed a significant increase (odds ratio 9 and 24 [1.3-59.3 and 2.3-240.3]) between these two groups.     

Role of methylenetetrahydrofolate reductase gene (MTHFR) 677C>T polymorphism in pediatric cerebrovascular disorders

Homozygosity for the methylenetetrahydrofolate reductase (MTHFR) 677C>T mutation (MTHFR TT) has been linked to an increased risk for stroke, coronary artery disease, and migraine headaches. The authors analyzed the potential link between MTHFR 677C>T homozygosity and childhood stroke. A true association might facilitate screening, recurrence risk stratification, and treatment in patients with cerebrovascular disease. They performed a retrospective chart review of children tested for the MTHFR 677C>/T mutation; 533 patients underwent MTHFR testing, and 8% were homozygous for the MTHFR 677C>T mutation. There was no difference in the cohort compared with the prevalence in the general population. This suggests that the MTHFR 677 C>T polymorphism played a minimal role or no role in stroke risk. However, the data suggest that the MTHFR TT genotype may influence migraine susceptibility in children because there was a higher proportion of migraine patients (28.6%) with the MTHFR TT homozygous genotype.     

Acute stroke in relation to homocysteine and methylenetetrahydrofolate reductase gene polymorphisms

AIM: Some methylenetetrahydrofolate reductase (MTHFR) gene mutations cause hyperhomocysteinemia and homocystinuria. These may be important risk factors for cardio and cerebrovascular diseases. We investigated whether the MTHFR C677T and A1298C polymorphisms contribute to hyperhomocysteinemia and increase the risk factor for stroke. METHODS: A total of 203 acute stroke patients and 55 controls were recruited. Polymorphisms were determined by using polymerase chain reaction-restriction fragment length polymorphism (RFLP) and plasma total homocysteine levels were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS AND CONCLUSIONS: There were no significant differences between C677T and A1298C genotypes and allele frequencies in the stroke patients and controls. Total plasma homocysteine level was higher in the 677TT and 1298AA genotypes in stroke patients and especially small-vessel disease patient subgroup. Age, number of males, systolic-diastolic blood pressures, creatinine, vitamin B(12) and homocysteine levels were significantly high among stroke patients. Age, sex, systolic blood pressure and HDL-C were determined as risk factors for homocysteine levels. We also determined that the effect of A1298C polymorphism on homocysteine was not as high as that of C677T polymorphism in acute stroke patients. We conclude that the MTHFR genotype may be a modest risk factor for stroke in Turkish population.     

亚甲基四氢叶酸还原酶基因C677T多态与2型糖尿病脑梗死的关系

目的　探讨亚甲基四氢叶酸还原酶 (methylenetetrahydrofolate reductase,MTHFR)基因 C6 77T多态与中国东北汉族 2型糖尿病患者合并脑梗死的关系。方法　应用聚合酶链反应 -限制性片段长度多态性 (PCR-RFL P)方法检测了对照组、2型糖尿病无大血管病变组和 2型糖尿病脑梗死组共 2 0 8名的 MTHFR基因 C6 77T多态性分布。结果　经 χ2检验 ,MTHFR基因各基因型频率在对照组、2型糖尿病组和 2型糖尿病脑梗死组之间均无显著性差异 (P>0 .0 5 ) ;各等位基因频率在 3组人群中均无显著性差异 (P>0 .0 5 )。结论　未发现 MTHFR基因C6 77T多态与 2型糖尿病脑梗死之间存在相关关系。     

Homocysteine, methylenetetrahydrofolate reductase C677T polymorphism and cognitive impairment: the health in men study

High total plasma homocysteine (tHcy) has been associated with cognitive impairment in later life, but it is unclear if this association is causal or is due to confounding. The C677T polymorphism of the 5,10 methylenetetrahydrofolate reductase gene (MTHFR) increases basal tHcy, but its contribution to cognitive impairment has not been established. We designed this study to determine if tHcy is causally related to cognitive impairment in later life by investigating its association with high tHcy and the MTHFR-C677T polymorphism. We recruited 1778 older men from the Health in Men Study cohort and established caseness on the basis of the participants' scores on a Telephone Interview for Cognitive Status score 27 in 2008. Exposure to tHcy, gene status and other variables of interest were obtained from assessments 4-7 years earlier. Multivariate logistic regression showed that the odds of cognitive impairment increased with a doubling of tHcy (adjusted odds ratio, OR 1.36; 95% confidence interval, 95% CI 1.02-1.82). Compared with the wild CC genotype, participants with the MTHFR-TT genotype had 46% greater odds of cognitive impairment (OR 1.46, 95% CI 1.01-2.11, P=0.043). The results of this study are consistent with, but do not prove the hypothesis that high tHcy causes cognitive impairment in later life.