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

Thrombotic and thromboembolic complications are the main causes of morbidity and mortality in patients with homocystinuria. However, it is unusual for thrombosis and infarction to be the presenting feature leading to investigation for homocystinuria and cerebrovascular lesions in the first year of life. We describe a previously healthy 6-month-old infant who presented with a large middle-cerebral-artery territory infarction and died of massive brain swelling. Homocystinuria due to cystathionine beta-synthase (CBS) deficiency was diagnosed by metabolite analysis and confirmed by enzymatic activity measurement in a postmortem liver biopsy. Homocystinuria should be considered in the differential diagnosis of venous or arterial thrombosis, regardless of age, even in the absence of other common features of the disease. We recommend systematic metabolic screening for hyperhomocysteinemia in any child presenting with vascular lesions or premature thromboembolism.
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PMID:Fatal haemorrhagic infarct in an infant with homocystinuria. 1007