title: A genetic variant of factor IX with decreased capacity for Ca2+ binding.
abstract: A genetic variant of factor IX is described that behaves identically to PIVKA/IX (the precursor factor IX molecule induced by the absence of vitamin K or presence of vitamin K antagonists, acarboxy factor IX). It shows an increased electrophoretic mobility in the presence of Ca2+, a low affinity for adsorption to A1(OH)3 and a very low specific coagulant activity. This variant of factor IX has been demonstrated in the plasma of a patient with severe haemophilia B and in the plasmas of a number of possible carriers from the probands' pedigree.
mesh_terms: D001665:Binding Sites; D002118:Calcium / Q000097:blood*; D005164:Factor IX / Q000032:analysis / Q000235:genetics*; D014644:Genetic Variation; D002836:Hemophilia B / Q000097:blood / Q000235:genetics; D006801:Humans; D007122:Immunoelectrophoresis; D010375:Pedigree; D011498:Protein Precursors / Q000097:blood
chemical_list: D011498:Protein Precursors; D005164:Factor IX; D002118:Calcium