Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.5.7.1 (methylenetetrahydrofolate reductase)
 2,116 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To study genetic mutations of methylenetetrahydrofolate reductase (MTHFR) C677T and cystathionine-beta-synthase (CBS) T833C related to homocysteine metabolism in patients with ischemic stroke, the MTHFR gene C677T gene mutation and the CBS T833C gene mutation were detected by PCR-RFLP or ARMS method in 74 patients with ischemic stroke and 83 normal people for control. Results showed that the frequencies of MTHFR T homogenetic type (2.7%) , heterogenetic type (51.4%) and T allele (28.4%) in ischemic group were higher than those in control group (1.2%, 39.8% and 21.1%, respectively). The frequencies of CBS C homogenetic type (13.5%) and C allele (43.9%) in ischemic group were higher than those in control group (6.0% and 38.0%, respectively). Multiple Logistic Regression analysis showed that together with the T allele in MTHFR, the C allele in CBS and age were related to ischemic stroke (P<0.05). The odds ratios (OR) of the T allele in MTHFR C677T and the C allele in CBS T833C were 1.74 (95%CI 1.06-2.86) and 1.73 (95%CI 1.07-2.81) respectively. The study revealed that the genetic mutations of MTHFR C677T, CBS T833C,were related with the ischemic stroke. The genetic mutations of MTHFR C677T and CBS T833C may be genetic factors for ischemic stroke.
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PMID:[Genetic mutations of homocysteine metabolism related enzymes in patients with ischemic stroke]. 1564 7

Hyperhomocysteinemia is considered one of the most important cardiovascular risk factors increasing considerably the risk of stroke and myocardial infarction. With respect to endothelial function, direct effects of hyperhomocysteinemia on vascular endothelial cells have been demonstrated through the reduction of endothelial nitric oxide production. In this paper, we report the case of a young man with homozygote genotype mutated with 5-methylenetetrahydrofolate reductase (MTHFR) thermolabile variant who, in the absence of relational stress, developed an erectile dysfunction (ED) refractory to the vasoactive type-V phosphodiesterase (PDE5) inhibitor therapy. After one month of treatment with 5 mg/day folic acid and 1000 microg/day cyanocobalamin, the patient restarted the assumption of 50 mg sildenafil, obtaining satisfying erections during sexual intercourse. We suggest that hyperhomocysteinemia may interfere with penile blood supply and, thus, be responsible for ED. If this relationship is confirmed, plasma levels and urinary homocysteine (HCy) should be evaluated in selected young patients with vascular ED. Furthermore, careful attention should be given to the risk of ED when dealing with this metabolic disturbance.
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PMID:Might erectile dysfunction be due to the thermolabile variant of methylenetetrahydrofolate reductase? 1564 56

The authors report the case of a 39-year-old male patient who had an ischemic stroke (complete infarction of right anterior cerebral circulation) and an acute myocardial infarction during the same year. Molecular study revealed he was homozygous for the 677C-->T mutation in the gene coding for methylenetetrahydrofolate reductase, a key enzyme of folate metabolism; deficiency of this enzyme is associated with increased cardiovascular risk and neurological lesions. Some considerations are put forward about hyperhomocysteinemia and the MTHFR 677C-->T mutation as cardiovascular risk factors.
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PMID:The methylenetetrahydrofolate reductase (MTHFR) 677C-->T mutation and cardiovascular risk--A case of ischemic stroke and acute myocardial infarction. 1577 69

Elevated plasma total homocysteine (HCY) level is a risk factor for coronary heart disease and ischemic stroke. We investigated relationships between polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene, and plasma levels of HCY and folate in patients of Mongolian races who suffered from cerebral ischemia (CI, n = 42) or cerebral hemorrhage (CH, n = 20) and in the 24 age-matched controls. The incidences of both homozygous and heterozygous MTHFR gene mutations in CI (26 and 43%) and in CH (25 and 60%) were significantly higher than those in the controls (8 and 25%). Homozygous MTHFR gene mutation was associated with reduced plasma folate levels, but not with increased plasma HCY levels. Among the subjects with homozygous MTHFR gene mutation, plasma folate levels in CH was significantly lower than those in CI and controls. MTHFR gene mutation in CH was found to be as common as that in CI and was associated with reduced plasma folate levels in the both. In homozygous MTHFR gene mutation, the plasma folate level was profoundly reduced in CH as compared with CI and controls, suggesting that subjects with low plasma folate levels have a predisposition to intracerebral bleeding.
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PMID:Methylenetetrahydrofolate reductase gene polymorphisms in patients with cerebral hemorrhage. 1582 63

The present review focuses on the B-vitamins, i.e. folate, vitamin B12, vitamin B6 and riboflavin, that are involved in homocysteine metabolism. Homocysteine is a S-containing amino acid and its plasma concentrations can be raised by various constitutive, genetic and lifestyle factors, by inadequate nutrient status and as a result of systemic disease and various drugs. Hyperhomocysteinaemia is a modest independent predictor of CVD and stroke, but causality and the precise pathophysiological mechanism(s) of homocysteine action remain unproven. The predominant nutritional cause of raised plasma homocysteine in most healthy populations is folate insufficiency. Vitamin B12 and, to a lesser extent, vitamin B6 are also effective at lowering plasma homocysteine, especially after homocysteine lowering by folic acid in those individuals presenting with raised plasma homocysteine. However, riboflavin supplementation appears to be effective at lowering plasma homocysteine only in those individuals homozygous for the T allele of the C677T polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene. This gene codes for the MTHFR enzyme that produces methyltetrahydrofolate, which, in turn, is a substrate for the remethylation of homocysteine by the vitamin B12-dependent enzyme methionine synthase. Individuals with the MTHFR 677TT genotype are genetically predisposed to elevated plasma homocysteine, and in most populations have a markedly higher risk of CVD.
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PMID:B-vitamins, homocysteine metabolism and CVD. 1583 Nov 32

Pregnancy is considered to be a hypercoagulable state per se with an increased risk for cerebrovascular events, however cerebellar infarction has been rarely described in pregnant women. A nulliparous pre-eclamptic woman at 25 weeks' gestation was submitted to an echocardiographic exam that showed an impaired cardiac structure and function. After 2 h, the patient underwent caesarean section for diagnosis of haemolysis, elevated liver enzymes, low platelet (HELLP) syndrome. Afterwards her platelet count raised, and eight days later she developed nystagmus, ataxia, dysmetria and motor deficit in the right limbs and sensory impairment in the right side of the face and in the left limbs. Cerebral magnetic resonance imaging (MRI) demonstrated a right cerebellar and median posterior bulbar infarction. Colour-coded sonography of cerebral vessels showed an occlusion of the right vertebral artery. Coagulation pattern analysis evidenced double heterozygosis of the methylenetetrahydrofolate reductase (MTHFR) gene and single mutation of the prothrombin gene. This case report gives evidence of the importance of considering the different risk factors involved in stroke occurrence during pregnancy.
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PMID:Postpartum cerebellar infarction and haemolysis, elevated liver enzymes, low platelet (HELLP) syndrome. 1587 86

Hyperhomocysteinemia is a risk factor for ischemic stroke. We investigated five functional polymorphisms involved in homocysteine metabolism in each 159 stroke patients and controls. The folate-sensitive polymorphism methylenetetrahydrofolate reductase (MTHFR) c. 677 C > T (A222V) referred a non-significant risk of ischemic stroke (odds ratio: 1.20) in all patients, and homozygosity for MTHFR c. 677 C > T was associated with an earlier onset of stroke selectively in patients younger than 60 years (38 +/- 3 years vs. 45 +/- 1 years; P = 0.043). This study suggests that the investigated polymorphisms are no major risk factors for stroke, although MTHFR c. 677 C > T could be a minor factor of vulnerability especially in young patients (TT genotype), which might be helpful for the clinical work-up of stroke cases and for preventive dietary strategies.
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PMID:Common genetic variants of homocysteine metabolism in ischemic stroke: a case-control study. 1605 69

Although significant progress has been made in our understanding of sickle cell disease (SCD) and in the development of new therapies, many questions are still unanswered, and a cure remains elusive. This is particularly evident in the clinical heterogeneity of the disease. Studies have shown the importance of high hemoglobin F determinants and alpha-thalassemia as modifiers of disease severity, but these alone do not explain the diversity that is seen. This paper focuses on recent advances on the effect of nonglobin genetic modifiers on the SCD phenotype. The roles of polymorphic variants of (1) methylenetetrahydrofolate reductase gene in the pathogenesis of avascular necrosis, (2) factor V R485K and risk of venous thrombosis, and (3) UDP glucuronosyltransferase-1 polymorphism on serum bilirubin levels in SCD are discussed. Mention is made of genetic polymorphisms that might predispose to stroke. The application of gene expression profiling to the study of SCD is very promising and some preliminary data are provided.
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PMID:Sickle cell disease: a multigenic perspective of a single-gene disorder. 1610 9

The optimal anticoagulation following Fontan operation and its modifications remain controversial and it is even less well defined as regards patients with inherited thrombophilia. We present a case of a child with bidirectional Glenn anastomosis for double inlet left ventricle that suffered a stroke despite aspirin prophylaxis; the patient was combined homozygous for prothrombin G20210A mutation and for methylenetetrahydrofolate reductase C677T mutation as well. The family history was positive for fetal loss and premature cardiovascular disease. Large-scale studies are needed to evaluate whether carriers of thrombophilia mutations need more intense thromboprophylaxis.
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PMID:Stroke following Glenn anastomosis in a child with inherited thrombophilia. 1620 93

Although rare in children, stroke is becoming increasingly recognized as an important cause of morbidity and mortality with an annual incidence of approximately 3 per 100,000 per year. While several studies have documented the underlying mechanisms and pathogenesis related to stroke in adults, including genetic and acquired prothrombotic conditions, the data available on similar conditions in children is limited. Evidence suggests that mutations in methylenetetrahydrofolate reductase (MTHFR) appear to be linked with hyperhomocysteinemia (HHC) and cerebral-thrombotic events in children. While the C677T common missense mutation is the best-characterized MTHFR polymorphism, another common missense mutation, A1298C also exists. A recent study of children demonstrated that the homozygous form of C677T polymorphism occurred two-times as often in those with stroke versus healthy controls. In our retrospective chart review of 33 children seen at Children's Hospital of Orange County from January 1, 2000 to September 30, 2003 with the diagnosis of stroke, we examined both the C677T and A1298C polymorphisms for occurrence and type. In the subset (n=21), which excluded those with a confounding disorder, we observed a significant increase in the frequency of A1298C and C677T homozygosity (0.25 [p=0.01] and 0.20 [p=0.100], respectively); expected rate: (0.06 and 0.08, respectively). Our observed rates of heterozygosity for both MTHFR mutations (0.35 and 0.40, respectively) were consistent with expected rates (0.28 and 0.38, respectively). In all subjects, homocysteine (HC) levels were normal. The results of our study suggest that mutations in MTHFR are associated with pediatric stroke. However, additional studies are required to confirm our findings and to determine if this relationship is causal.
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PMID:Pediatric stroke and methylenetetrahydrofolate reductase polymorphisms: an examination of C677T and A1298C mutations. 1700 74


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