The data base below lists known point mutations and short deletions and additions in the factor IX gene, causing the bleeding disorder haemophilia B or Christmas disease (for reviews, see Brownlee 1988, Giannelli 1989, Thompson 1990, Green et al 1991a) These mutations result in a defective'clotting factor IX-a glycoprotein of 415 amino acid residues normally present in plasma and an essential c...

Hemophilia B is an X-chromosomal recessive disease due to deficiency of coagulation factor IX. Three monoclonal antibodies against factor IX were prepared and used to develop immunoradiometric assays (IRMAs) of factor IX antigen (IX-Ag). IX-Ag was measured in 65 normal individuals with one IRMA based on polyclonal anti-IX antibodies and two IRMAs based on three monoclonal anti-IX antibodies. On...

Bovine factor IX (Christmas factor) is a coagulation protein present in plasma in a precursor or inactive form. It is a glycoprotein (M, = 55,000) composed of a single polypeptide chain. Factor IX in the presence of calcium ions is converted to factor IX, by factor XI, (activated plasma thromboplastin antecedent) or a protease present in Russell’s viper venom. The activation of factor IX by the...

Human platelet glycoprotein Ib beta (GPIb beta) (M(r) 22,000) is part of the GPIb-V-IX system that constitutes the receptor for von Willebrand factor and mediates platelet adhesion in the arterial circulation. The four members of the receptor (GPs Ib alpha, Ib beta, V, and IX) share structural and functional features. Individually, GPIb beta contributes to surface expression of the receptor and...

Endothelium provides a specific binding site for Factor IX/IXa which can propagate activation of coagulation by promoting Factor IXa-VIII-mediated activation of Factor X. In this report the endothelial cell Factor IX/IXa binding site has been identified and the coagulant function of the receptor blocked. Studies using [3H]Factor IX derivatized with the photoaffinity labeling agent N-succinimidy...

introduction: duchene/ becker (dmd/bmd) muscular dystrophy is the most frequent neuromuscular disease in children which is inherited as an x-linked recessive trait. the disease is caused by partial deletion in dystrophin gene. we developed a rapid and robust method for direct identification of female carriers of deletions and duplications in the dystrophin gene, in order to prevent the affected...

Factor IX is a vitamin K-dependent blood clotting zymogen that is functionally defective or absent in patients with hemophilia B. A method of immunoaffinity chromatography has been developed for a one-step high yield purification of factor IX directly from plasma. The technique utilizes conformation-specific antibodies that bind solely to the metal-stabilized factor IX conformer, but not to the...

Factor IX is synthesized in a precursor form with a propeptide that contains the gamma-carboxylation recognition site, an element which directs the post-translational gamma-carboxylation of adjacent glutamic acid residues. After protein synthesis, the propeptide is cleaved to yield the mature Factor IX. To study propeptide processing, anti-proFactor IX antibodies were prepared using a synthetic...

The role of the factor IXa heparin-binding exosite in coagulation was assessed with mutations that enhance (R170A) or reduce (R233A) stability of the protease-factor VIIIa A2 domain interaction. After tissue factor (TF) addition to reconstituted factor IX-deficient plasma, factor IX R170A supported a 2-fold increase in velocity index (slope) and peak thrombin concentration, whereas factor IX R2...

The role of the factor IXa heparin-binding exosite in coagulation was assessed with mutations that enhance (R170A) or reduce (R233A) stability of the proteasefactor VIIIa A2 domain interaction. After tissue factor (TF) addition to reconstituted factor IX-deficient plasma, factor IX R170A supported a 2-fold increase in velocity index (slope) and peak thrombin concentration, whereas factor IX R23...