Acquired inhibitors to coagulation factors other than factor VIII are extremely rare. We describe a case of a 59-year-old woman with abnormal bleeding, diagnosed with concurrent inhibitor antibodies to factor VIII and IX by Bethesda testing. We demonstrate that anti-FVIII antibodies of a very high titre are capable of disturbing the aPTT-based Bethesda assay, resulting in falsely-positive antib...

Coagulation is initiated by the binding of factor VIIa to tissue factor, with resultant limited factor IX and X activation and thrombin production. Owing to the feedback inhibition of the factor VIIa/tissue factor complex by tissue factor pathway inhibitor (TFPI), additional factor X activation and thrombin generation must proceed through a pathway involving factors VIII, IX, and XI. Experiment...

The regulation of human Factor IXa was studied in vitro in human and mouse plasma and in vivo in the mouse. In human plasma, approximately 60% of the 125I-Factor IXa was bound to antithrombin III (ATIII) by 2 h, with no binding to alpha 2-macroglobulin or alpha 1-proteinase inhibitor, as assessed by gel electrophoresis and IgG- antiproteinase inhibitor-Sepharose beads. In the presence of hepari...

Three patients with Christmas disease whose plasma was shown to have a prolonged one-stage prothrombin time with ox brain thromboplastin have been investigated. These patients have an inhibitor for the reaction between factor X, factor VII, and ox brain extract. The abnormal constituent responsible for this inhibitor appears to be factor IX whuch is functionally inactive but antigenically indis...

background: heterogeneous mutations in the human coagulation factor ix gene lead to an x-linked recessive bleeding disorder known as hemophilia b. the disease is distributed worldwide with no ethnic or geographical priority. materials and methods: the aim of this study was to characterize the factor ix gene mutations in 28 unrelated iranian hemophilia b patients. polymerase chain reaction (pcr)...

Factor IX concentrates have been widely advocated in the treatment of haemophilic patients with factor VIII inhibitors. Five such patients were given the 'activated' factor IX concentrate--factor VIII inhibitor bypassing activity (Feiba)--for 14 separate bleeding episodes. In six of the episodes, including two with external blood loss, bleeding progressed in spite of treatment. In none of the o...

Background: Hemophilia B is an X-linked recessive coagulation disorder caused by factor IX deficiency.  Analysis of factor IX gene polymorphisms is considered the best approach for prenatal diagnosis and carrier detection of hemophilia B where the identification of gene mutation is not easily possible. Objective: To study the frequency of three factor IX-linked restriction fragment length polym...

The eighth edition of the haemophilia B database (http://www.umds.ac. uk/molgen/haemBdatabase.htm ) lists in an easily accessible form all known factor IX mutations due to small changes (base substitutions and short additions and/or deletions of <30 bp) identified in haemophilia B patients. The 1713 patient entries are ordered by the nucleotide number of their mutation. Where known, details are...

The structure of factor IX gene was analyzed in a hemophilia B patient with inhibitor. Genomic DNA, digested with a variety of restriction endonucleases, was hybridized with the cDNA and various genomic factor IX probes. A large subtotal deletion of the gene was observed. The borders of the deletion span from a approximately 125 nucleotide region within the last exon to an unknown domain at lea...