Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.2.1.22 (cystathionine beta-synthase)
 965 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

In order to determine if cystathionine beta-synthase (CBS) could separate groups of patients with various vascular disease, CBS activity was studied in cultured human skin fibroblasts from 30 subjects being either controls, atherosclerotic patients or patients having suffered a deep venous thrombosis. We found a tendency to a negative correlation between age and CBS activity in the control group only (r = -0.58, P = 0.08), with a tendency to lower CBS activities in the young patients with atherosclerotic (4.9) or venous disease (5.3) compared to the young control group (10.2). This could implicate higher levels of p-homocysteine with increased age as well as in young patients with atherosclerotic or thrombotic disease causing vascular damage. The results are important for the further discussion of the role of homocysteine as a risk factor for developing atherosclerotic and thrombogenic vascular disease and for finding a suitable screening method as prevention is by vitamin supplement only.
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PMID:Age and cystathionine beta-synthase activity in cultured fibroblasts from patients with arterial and venous vascular disease. 971 28

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

Objective Homocystinuria is an inborn error of amino acid metabolism caused by cystathionine beta-synthase deficiency that affects methionine metabolism. The clinical features are heterogeneous ranging from mental retardation, ectopia lentis, and osteoporosis to vascular events such as deep vein thrombosis, sagital sinus thrombosis, and myocardial infarction. Cerebral sinovenous thrombosis (CVST) is an unusual disorder in children and requires prompt and accurate management. Some causal factors for the development of CVST differ between children and adults. The majority of cases with CSVT are found to have an underlying cause for thrombosis like dehydration, infections, prothrombotic and hematologic disorders, malignancy and trauma. Although homocystinuria is usually associated with ischemic strokes, CVST as initial clinical presentation of homocystinuria is rare in children. In this article, we presented a 10-year old boy with seizure, hemiparesis, and ataxia due to CSVT caused by homocystinuria.
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PMID:Homocystinuria: A Rare Disorder Presenting as Cerebral Sinovenous Thrombosis. 2622 Nov 64