Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.69 (APC)
 16,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report a case of hepatocellular carcinoma associated with portal vein thrombosis. Analysis of whole cellular DNA demonstrated heterozygosity for the factor V Leiden mutation. The patient also had marked protein C deficiency. The presence of the mutation associated with protein C deficiency may increase the risk of thrombosis in this patient with hepatocellular carcinoma.
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PMID:Portal vein thrombosis in association with factor V Leiden mutation in a patient with hepatocellular carcinoma. 921 50

The most common commercially available test measuring activated protein C (APC) resistance relies on the the anticoagulant response to added APC in an activated partial thromboplastin time (APTT) based method. Another method is a Russell Viper venom time (RVVT) based system. To improve the specificity for factor V Leiden of the APTT based method, pre-dilution of test plasma in FV-deficient plasma has recently been recommended. In this study we tested the relative suitabilities of the APTT-based system, the RVVT-based system and their corresponding assays modified by pre-dilution in FV-deficient plasma, for screening asymptomatic subjects, a group of thrombophilic patients (in particular those with low APC ratios), patients on oral anticoagulants, and patients with lupus anticoagulant (LAC). We found the RVVT-based assay to be superior to the APTT-based method in the separation of normals from those with FV Leiden mutation both in asymptomatic subjects and in the thrombophilic patient group. Both modified assays demonstrated a sensitivity and specificity of 100% for FV Leiden, as verified by genotyping in asymptomatic subjects, thrombophilic patients and patients on oral anticoagulants, with the modified RVVT-based assay giving better separation between normals and FV Leiden. Inhibition of phospholipid-dependent coagulation by LAC antibodies rendered the APTT-based system less suitable than the phospholipid-rich RVVT-based one, and as nine of the 20 LAC-positive patients were on warfarin, we showed only the modified RVVT assay to be a reliable predictor of factor V Leiden in this patient group.
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PMID:A comparison between two activated protein C resistance methods as routine diagnostic tests for factor V Leiden mutation. 921 78

Venous thromboembolism is a serious, potentially lethal health problem affecting one per 1,000 people annually. Major surgery, the use of oral contraceptives, complicated pregnancy, fractures, and immobilization increase the risk of thrombosis. In addition to these factors, thrombosis is associated with inherited deficiencies of antithrombin III, protein C, and protein S. Together these do not account for more than five to 10% of the cases. Hereditary activated protein C resistance has been recognized as a basis for a majority of cases of familial thrombosis. It accounted for more than a 10 times higher number than that of other known genetic defects. We describe a case of a young female who presented with a pulmonary embolism and was discovered to have activated protein C resistance. This patient had a heterozygous mutation for factor V Leiden and was taking oral contraceptives. This report underlines: 1) increased risk of venous thrombosis in oral contraceptive users who carry factor V Leiden mutation associated with functional resistance to the normal anticoagulation activities of protein C; 2) most episodes occurring in the young are minor, but pulmonary embolus can occur; 3) the importance of identifying other affected members of the family; and 4) the importance of anticoagulation prophylaxis at times of enhanced risk, particularly during pregnancy, postpartum, and major surgery.
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PMID:Life threatening pulmonary embolus in a factor V Leiden carrier on oral contraceptives: a case report. 923 27

Annually, 1 in 1,000 individuals is affected by venous thrombosis. Risk factors that are known to increase the risk of thrombosis may be either genetic or acquired, or have a combined origin. Many of these risk factors are very frequent, among which several have been recently identified, such as resistance to activated protein C by factor V Leiden, hyperhomocysteinemia, high levels of factors VIII, as well as the classical acquired risk factors, such as surgery and malignancies. When the prevalence of risk factors is high, it becomes likely that in some individuals two or more risk factors will be present simultaneously. The question "What happens to the risk in these circumstances?" is one involving interaction, also known as effect modification or synergy. In this article we review the prevalence and risk estimates for the various genetic and acquired risk factors for venous thrombosis, discuss the concept of interaction, and give an overview of the evidence for interaction of these risk factors.
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PMID:Risk factors for venous thrombosis: prevalence, risk, and interaction. 924 4

Familial thrombosis has long been considered as an autosomal dominant trait, caused by a dominant gene defect with a reduced penetrance for the disease. Recently, this view has changed and today familial thrombophilia is considered as a complex genetic disorder caused by the segregation of two or more gene defects (known and unknown) in a family. Here we briefly discuss the known genetic defects (protein C, protein S, and antithrombin deficiency and activated protein C resistance associated with factor V Leiden) with special focus on the relation between gene mutation and plasma abnormality and on the association between abnormality and thrombosis in affected families and in the population. Finally, the evidence is reviewed that indicates familial thrombosis as an oligogenetic disorder and on the basis of these data strategies are discussed for the identification of new genetic risk factors for thrombosis via a genetic approach.
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PMID:Familial thrombophilia: a complex genetic disorder. 924 10

Purpura fulminans is associated with homozygous protein C and homozygous protein S deficiency or may follow bacterial or viral infections. We present 2 children from 2 unrelated Arab families with purpura fulminans who were double heterozygotes for factor V Leiden inherited from their fathers and protein S deficiency inherited from their mothers. No previous thrombotic events have occurred in either patient or their respective family members. In one patient sepsis accompanied by disseminated intravascular coagulation appeared to be the trigger of purpura fulminans. In the other patient varicella infection preceded purpura fulminans and was also associated with disseminated intravascular coagulation. This report emphasizes the need for evaluation of hereditary defects in the inhibitory mechanisms of blood coagulation in patients with purpura fulminans at any age.
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PMID:Purpura fulminans induced by disseminated intravascular coagulation following infection in 2 unrelated children with double heterozygosity for factor V Leiden and protein S deficiency. 924 37

We describe a novel hemi-nested, allele specific whole blood PCR assay for detection of the factor V Leiden mutation associated with the plasma defect, activated protein C resistance. This assay utilizes 5 microliters of whole blood without prior DNA extraction. The hemi-nested design, employing an outer primer pair in combination with nested, allele specific primers obviates the need for restriction enzyme digestion. PCR reactions are analysed directly on agarose or polyacrylamide minigels. The assay confirmed the genotypes of 50 individuals previously categorized by PCR and Mn11 digestion, and has been subsequently utilized in the genotyping of 445 individuals referred for thrombosis studies.
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PMID:A hemi-nested, allele specific, whole blood PCR assay for the detection of the factor V Leiden mutation. 924 49

Recurrent fetal loss and other placental vascular pathologies of pregnancy have long been associated with antiphospholipid syndrome-an acquired autoimmune thrombophilic state. The number of known heritable thrombophilic disorders has grown rapidly in recent years with the identification of activated protein C resistance, factor V Leiden mutation and hyperhomocysteinemia as major causes of thrombosis. Data accumulated over the past two years suggest that heritable thrombophilia is associated with increased risk of fetal loss and pre-eclampsia. The present review discusses potential pathogenetic mechanisms for this association and evaluates reported therapeutic regimes for the prevention of fetal loss in women with thrombophilia.
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PMID:Thrombophilia and fetal loss. 924 90

The etiology of migrainous cerebral infarction is unknown, but may involve prothrombotic coagulation abnormalities. Therefore, we studied resistance to activated protein C and the presence of the Arg506Gln factor V Leiden mutation in 20 patients with migrainous cerebral infarction. Only one heterozygous carrier of the mutation was found, whereas other patients did not carry the mutation. This indicates that the factor V Leiden mutation is not a major risk factor for migrainous cerebral infarction.
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PMID:The factor V Leiden mutation (R506Q) is not a major risk factor for migrainous cerebral infarction. 925 78

Few studies of activated protein C resistance (APCR) and thromboembolism in childhood have been published. In the majority of childhood thromboses reported, the factor V Leiden mutation was associated with venous thromboses; however, one case report and three studies described arterial thromboembolism in infants and children due to the common mutation in the factor V gene. In one neonate purpura fulminans occurred, and heparin-induced thrombocytopenia type II was additionally documented. Two case reports and seven of nine studies reported associated clinical conditions together with inherited coagulation disorders. In three studies homozygous patients were mentioned. There are few studies describing the interaction between APCR and coagulation or the fibrinolytic system in symptomatic and nonsymptomatic infants. Compared with healthy brothers or sisters and a healthy age-matched control group, thrombin generation, D-dimer, PAI-1 activity, and t-PA antigen were found clearly elevated in children with APCR. In addition, infants and children with the Arg506-to-Gln mutation in the factor V gene showed significantly increased thrombomodulin concentrations along with normal protein C activities compared with relatives and healthy controls. No difference was recorded in these studies between heterozygous infants and children without vascular occlusion and patients who previously had suffered from thromboembolism. Until long-term data are available for the treatment of patients with APCR, such children should be treated in the same way as patients with deficiencies of protein C, protein S, or antithrombin.
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PMID:APC resistance in childhood thromboembolism: diagnosis and clinical aspects. 925 6


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