Inherited resistance to activated protein C (APC), which is caused by a single point mutation in the gene for factor V, is a common risk factor for thrombosis. In this study, the prevalence of APC resistance in 18 unrelated thrombosis-prone families with inherited protein S deficiency was investigated to determine its role as additional genetic risk factor for thrombosis. In addition, a detaile...

Protein Z (PZ) is a vitamin K-dependent factor identified in human plasma in 1984 characterized by an homology with other vitamin K-dependent factors (factor VII, IX, X, protein C). In contrast to these factors, PZ does not possess any enzymatic activity but is involved as a cofactor in the down-regulation of coagulation by forming a complex with the protein Z-dependent protease inhibitor (ZPI)...

Studies were performed on a French-Canadian family afflicted with a bleeding disorder exhibiting an autosomal dominant inheritance pattern and a severe bleeding diathesis after trauma. Clinical laboratory coagulation tests were unimpressive; the only persistent abnormalities include mild thrombocytopenia and moderately reduced Factor V clotting activities. Some individuals had prolonged Stypven...

A new case of combined factor V-VIII deficiency is reported with in vitro studies of factors V and VIII activation by thrombin. The normal activation of factors V and VIII demonstrated in the patient's plasma and the equivalent levels of factor VIII coagulant activity and coagulant antigen support the hypothesis that a quantitative rather than qualitative defect in factors V and VIII is present...

The type II and type III mutations at the FXI locus, which cause coagulation factor XI deficiency, have high frequencies in Jewish populations. The type III mutation is largely restricted to Ashkenazi Jews, but the type II mutation is observed at high frequency in both Ashkenazi and Iraqi Jews, suggesting the possibility that the mutation appeared before the separation of these communities. Her...

Protein Z (PZ) is a plasma vitamin K-dependent protein that functions as a cofactor to dramatically enhance the inhibition of coagulation factor Xa by the serpin, protein Z-dependent protease inhibitor (ZPI). In vitro, ZPI not only inhibits factor Xa in a calcium ion-, phospholipid-, and PZ-dependent fashion, but also directly inhibits coagulation factor XIa. In murine gene-deletion models, PZ ...

stroke, though rare in children is among the top 10 causes of death in childhood. incidence of ischemic and hemorrhagic stroke is the same in children .we report a case of hemorrhagic stroke in a two year old girl who presented with a limp, inability to stand on the left leg and left hemiparesia. her complaint began 10 days ago after a bout of left clonic seizure. she had been admitted to the h...