Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0034065 (pulmonary embolism)
 14,979 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Severe hyperhomocysteinemia in its most frequent form, is caused by a homozygous enzymatic deficiency of cystathionine beta-synthase (CBS). A major complication in CBS deficiency is deep venous thrombosis or pulmonary embolism. A recent report by Mandel et al (N Engl J Med 334:763, 1996) postulated factor V Leiden (FVL) to be an absolute prerequisite for the development of thromboembolism in patients with severe hyperhomocysteinemia. We studied 24 patients with homocystinuria caused by homozygous CBS deficiency from 18 unrelated kindreds for FVL and for the 677C-->T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene and investigated their possible interaction in the risk of venous thrombosis. Thrombotic complications were diagnosed in six patients, of whom only one was a carrier of FVL. On the contrary, thermolabile MTHFR caused by the 677C-->T mutation, was frequently observed among homocystinuria patients, especially among those with thromboembolic complications: three of six homocystinuria patients who had suffered from a thromboembolic event had thermolabile MTHFR. These data indicate that FVL is not an absolute prerequisite and probably not even a major determinant of venous thrombosis in homocystinuria, but, interestingly, thermolabile MTHFR may constitute a significant risk factor for thromboembolic complications in this inborn error of methionine metabolism.
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PMID:Homozygous cystathionine beta-synthase deficiency, combined with factor V Leiden or thermolabile methylenetetrahydrofolate reductase in the risk of venous thrombosis. 949 Jun 85

Hyperhomocysteinemia is a risk factor of venous thromboembolism. The risk of recurrence in patients with hyperhomocysteinemia is unknown, and the optimal therapy for these patients after acute venous thromboembolism is uncertain. In a multicenter study, 264 patients with an objectively documented single episode of idiopathic venous thromboembolism were prospectively followed after discontinuation of oral anticoagulants. Patients were classified as hyperhomocysteinemic if their homocysteine levels exceeded the 95th percentile of the controls. The outcome events studied were objectively confirmed deep-vein thrombosis and/or pulmonary embolism. Homocysteine levels were elevated in 66 patients (25%) and normal in 198 patients (75%). Recurrent venous thromboembolism occurred in 12 of 66 patients with hyperhomocysteinemia (18.2%) and in 16 of 198 patients without hyperhomocysteinemia (8.1%). The cumulative probability of recurrence 24 months after discontinuation of oral anticoagulants was 19.2 percent (95 percent confidence interval 8.7-27) in patients with hyperhomocysteinemia and was 6.3 percent (95 percent confidence interval 2.4-10.1; p = 0.001) in those without hyperhomocysteinemia. The relative risk of recurrent thrombosis was higher in patients with hyperhomocysteinemia [RR 2.7 (1.3-5.8), p = 0.009]. Patients with hyperhomocysteinemia are at high risk of recurrent venous thromboembolism. The high prevalence of hyperhomocysteinemia in thrombosis patients together with the increased risk of recurrence warrants extended patient screening. The impact on the risk of recurrence of prolonged anticoagulation, supplementation of folate and vitamin B12, or both have to be investigated.
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PMID:Hyperhomocysteinemia is a risk factor of recurrent venous thromboembolism. 979 70

A 45-year-old man was admitted complaining of chest pain and pain and edema in the left lower extremity. Ultrasonography and venography results yielded a diagnosis of left femoral vein thrombosis, and pulmonary embolism was diagnosed later. Intravenous heparin therapy (10,000 IU/day) improved the patient's clinical signs. During this therapy, however, pain and edema of the right lower extremity developed, leading to a diagnosis of right femoral vein thrombosis. The patient was admitted to our hospital. At that time, coagulation studies showed an FDP level of 44.7 micrograms/ml and an FDP-DD level of 24.5 micrograms/ml. We surmised that the bilateral deep vein thrombosis had been caused by hyperhomocysteinemia (17.8 mumol/l). Genetic and other acquired risk factors for thrombophilia were ruled out. The patient's clinical signs again improved as a result of intravenous heparin therapy (15,000 IU/day), and FDP and FDP-DD levels returned to normal. We concluded that hyperhomocysteinemia is a risk factor for thrombosis and that it can generate thrombosis in other locations even during heparin therapy.
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PMID:[Hyperhomocysteinemia: development of deep vein thrombosis in another location during heparin anticoagulation therapy]. 1039 Aug 88

Homocysteine is a sulfur-containing amino acid intermediate involved in two metabolic pathways, in the remethylation to methionine and in the transsulfuration to cysteine. Severe hyperhomocysteinemia (> 100 mumol/l) is found in congenital homocystinuria. Moderate (15-30 mumol/l) or intermediate (> 30-100 mumol/l) hyperhomocysteinemia is caused by defects in genes encoding for enzymes of homocysteine metabolism or by inadequate intake of those vitamins that are involved in homocysteine metabolism (folic acid, cobalmin, and vitamin B6). Today, hyperhomocysteinemia should be considered an important risk factor for atherosclerotic vascular and venous thromboembolic diseases. Homocysteine-plasma levels above the 95th percentile were found to be associated with a 2 to 3-fold elevated relative risk for deep-vein thrombosis and pulmonary embolism. Moreover, mild hyperhomocysteinemia has been shown to be associated with a 2 to 4-fold increased relative risk for coronary artery disease, cerebrovascular disease, and peripheral arterial occlusive disease. Several mechanisms have been proposed by which hyperhomocysteinemia contributes to atherogenesis and thrombogenesis. Several studies have shown that hyperhomocysteinemia can be corrected by supplementation of folic acid, cobalamin and vitamin B6. Clinical trials are urgently needed which investigate the preventive effect of supplementation of these vitamins on thrombotic diseases.
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PMID:[Hyperhomocysteinemia: a risk factor for arterial and venous thrombosis]. 1061 53

Homocystinuria (HCU) due to cystathionine beta-synthase (CBS) deficiency leads to severe hyperhomocysteinemia (HHcy). Vascular events (VE) remain the major cause of morbidity and mortality in the untreated patients with HCU. The study on the natural history of untreated HCU disclosed that, at the time of maximal risk, in other words beyond 10 years old, there was one event per 25 years. Recent studies from Australia (n = 32), The Netherlands (n = 28), and Ireland (n = 24) have documented the effects of long-term treatment on the vascular outcome of a total of 84 patients with 1314 patient-years of treatment for HCU. The mean (range) age was 27.8 (2.5 to 70) years. Five VE were recorded during treatment; one pulmonary embolism, two myocardial infarctions, and two abdominal aneurysms. All five VE occurred in B6-responsive patients at a mean (range) age of 48.8 (30 to 60) years. In 1314 patient-years of treatment, 53 VE would have been expected if they remained untreated; instead only 5 were documented, relative risk = 0.091 (95% confidence interval [CI] 0.043 to 0.190; p < 0.001). Appropriate homocysteine-lowering therapy for severe HHcy significantly reduced the vascular risk in patients with HCU. VE were rare with treatment despite the fact that the post-treatment homocysteine levels were several times higher than the cutoff point for homocysteine in the normal population. The present findings may have relevance to the current concept of "mild HHcy" as a risk factor for vascular disease, with elevated plasma homocysteine levels considerably lower than that of the post-treatment levels in this group of reported patients.
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PMID:Vascular complications of severe hyperhomocysteinemia in patients with homocystinuria due to cystathionine beta-synthase deficiency: effects of homocysteine-lowering therapy. 1101 51

Atrophic gastritis is an autoimmune gastropathy in which there is destruction of gastric parietal cells. This results in intrinsic factor deficiency and disturbance in vitamin B12 absorption. Its clinical manifestationa are therefore the consequences of B12 deficiency and include anemia and neurological defect. In addition, lack of B12 results in metabolic changes, including disturbances of methionine metabolism and accumulation of homocysteine. In recent years, there has been increasing evidence suggesting that hyperhomocysteinemia is a risk factor for thrombo-embolic disease. We describe a 51-year-old man with atrophic gastritis, severe B12 deficiency and hyperhomocysteinemia. The initial clinical manifestation was pulmonary embolism, without either anemia or neurological signs. B12 deficiency should therefore be considered in patients being investigated for hypercoagulability.
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PMID:[Atrophic gastritis presenting with pulmonary embolism]. 1134 Nov 83

Authors discussed the known risk factors of venous thromboembolism (VTE), which is complex disease with two manifestations: deep venous thrombosis (DVT) and pulmonary embolism (PE). Acquired risk factors of VTE are following: age over 40 years, bed rest, surgery, trauma, cancer, myocardial infarction, ischemic stroke, use of oral contraceptives, hormone-replacement therapy, pregnancy and puerperium, previous VTE, long lasting travel and presence of antiphospholipid antibodies. Group of genetic defects predisposing to thromboembolic events are called thrombophilia. The best known causes of thrombophilia are: resistance to activated protein C (factor V Leiden), the prothrombin 20210A, protein C deficiency, protein S deficiency, antithrombin deficiency, hyperhomocysteinemia and abnormality in the fibrinolytic system. Genetic predisposition to thrombosis may be detected in up to one-third of patients with VTER and more than 50% of patients with familial thrombosis. Detection of factor V Leiden is important for patients: with recurrent incidences of VTE, with other known causes of thrombophilia and in members of families with frequent occurrence of VTE. It is important also to detect deficiency of: protein C, protein S and especially of antithrombin in patient with previous VTE, because such patients have 8 to 10 fold increase risk of next incident of VTE. Chronic prevention of thrombosis should be used in all these cases.
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PMID:[Risk factors of venous thromboembolism]. 1155 14

Venous thrombosis, whose main clinical presentations include deep vein thrombosis and pulmonary embolism, represents a major health problem worldwide. Numerous conditions are known to predispose to venous thrombosis and these conditions are commonly referred to as risk indicators or risk factors. Generally accepted or "classically" acquired risk factors for venous thromboembolism include advanced age, prolonged immobilisation, surgery, fractures, use of oral contraceptives and hormone replacement therapy, pregnancy, puerperium, cancer and antiphospholipid syndrome. In addition to these well-established risk factors for venous thrombosis, several lines of evidence that have emerged over the past few decades indicate a role of novel genetic risk factors, mainly related to the haemostatic system, in influencing thrombotic risk. The most significant breakthrough has been the confirmation of the concept that inherited hypercoagulable conditions are present in a large proportion of patients with venous thromboembolic disease. These include mutations in the genes that encode antithrombin, protein C and protein S, and the factor V Leiden and factor II G20210 A mutations. Moreover, plasmatic risk indicators, such as hyperhomocysteinemia and elevated concentrations of factors II, VIII, IX, XI and fibrinogen, have also been documented. This extensive list of genetic and acquired factors serves to illustrate that a single cause of venous thrombosis does not exist and that this condition should be considered as a complex or multifactorial trait. Complex traits can be understood by assuming an interaction between different mutations in candidate susceptibility genes. The risk that is associated with each genetic defect may be relatively low in isolation but the simultaneous presence of several mutations may dramatically increase disease susceptibility. Moreover, environmental factors may interact with one or more genetic variations to add further to the risk. The analysis of genetic risk factors and plasmatic factors, together with private life style and environmental factors, has contributed significantly to our understanding of the genetic predisposition to venous thrombosis.
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PMID:Genetic risk factors of venous thrombosis. 1170 18

An inborn error of metabolism, homocystinuria due to cystathionine beta-synthase deficiency, results in markedly elevated levels of circulating homocysteine. Premature vascular events are the main life-threatening complication. Half of all untreated patients have a vascular event by 30 years of age. We performed a multicenter observational study to assess the effectiveness of long-term homocysteine-lowering treatment in reducing vascular risk in 158 patients. Vascular outcomes were analyzed and effectiveness of treatment in reducing vascular risk was evaluated by comparison of actual to predicted number of vascular events, with the use of historical controls from a landmark study of 629 untreated patients with cystathionine beta-synthase deficiency. The 158 patients had a mean (range) age of 29.4 (4.5 to 70) years; 57 (36%) were more than 30 years old, and 10 (6%) were older than 50 years. There were 2822 patient-years of treatment, with an average of 17.9 years per patient. Plasma homocysteine levels were markedly reduced from pretreatment levels but usually remained moderately elevated. There were 17 vascular events in 12 patients at a mean (range) age of 42.5 (18 to 67) years: pulmonary embolism (n=3), myocardial infarction (n=2), deep venous thrombosis (n=5), cerebrovascular accident (n=3), transient ischemic attack (n=1), sagittal sinus thrombosis (n=1), and abdominal aortic aneurysm (n=2). Without treatment, 112 vascular events would have been expected, for a relative risk of 0.09 (95% CI 0.036 to 0.228; P<0.0001). Treatment regimens designed to lower plasma homocysteine significantly reduce cardiovascular risk in cystathionine beta-synthase deficiency despite imperfect biochemical control. These findings may be relevant to the significance of mild hyperhomocysteinemia that is commonly found in patients with vascular disease.
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PMID:Vascular outcome in patients with homocystinuria due to cystathionine beta-synthase deficiency treated chronically: a multicenter observational study. 1174 88

Fasting plasma homocysteine level and the related clinical findings were analysed in 240 consecutive patients with venous thromboembolism. Hyperhomocysteinemia, defined as a plasma level above 20 micromol/l (corresponding to the percentile 95th in the controls), was present in 11.2% of the patients. Plasma homocysteine level was similar in patients presenting with either deep venous thrombosis, pulmonary embolism or both conditions. It was significantly higher in patients with primary (unprovoked) VTE than in patients with secondary disease (associated with at least one risk factor): 12.3 vs. 9.55 micromol/l (p < 0.005). Mean homocysteine was higher in male than in female patients (14.51 vs. 12.9 micromol/l, p < 0.05) and increased significantly with age. Hyperhomocysteinemia was more frequent in patients with relapsing disease (14 of 76, 18.4%) than in those presenting with a single episode (13 of 164, 7.9%) (p = 0.034). Furthermore, hyperhomocysteinemia was correlated with reduced protein C level (p = 0.013). In a multivariate analysis, two factors were significantly associated with hyperhomocysteinemia: older age (p < 0.0001) and idiopathic occurrence (p < 0.02). Since the frequency of homozygous MTHFR thermolabile variant was rather similar in patients and controls, testing for C677T mutation was not helpful in screening VTE patients. However, the homozygous mutation was significantly more prevalent among hyperhomocysteinemia patients, confirming its role in the genesis of hyperhomocysteinemia. According to its prevalence, to the putative role in venous and arterial disease and the availability of an effective and low-cost corrective therapy, hyperhomocysteinemia deserves interest, especially in the elderly and in the patients with idiopathic VTE disease.
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PMID:Hyperhomocysteinemia and venous thromboembolism: a risk factor more prevalent in the elderly and in idiopathic cases. 1218 10


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