A Genetic Variant of Factor IX with Decreased Capacity for Ca2+Binding

Abstract

A genetic variant of factor IX behaved 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 showed an increased electrophoretic mobility in the presence of Ca2+, a low affinity for adsorption to Al(OH)3 and a very low specific coagulant activity. This variant of factor IX was demonstrated in the plasma of a patient with severe hemophilia B and in the plasmas of a number of possible carriers from the probands'' pedigree.