What is pediatric factor VII deficiency?

Updated: Jun 22, 2021
  • Author: Helge Dirk Hartung, MD; Chief Editor: Hassan M Yaish, MD  more...
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Inherited factor VII (FVII) deficiency is a rare autosomal recessive hemorrhagic disorder. [1, 2] Clinical bleeding can widely vary and does not always correlate with the level of factor VII coagulant activity measured in plasma.

Factor VII is one of the vitamin K–dependent coagulation factors synthesized in the liver. It is present in plasma in low concentrations (0.5 mcg/mL) and has a short circulating half-life of 3-4 hours. Plasma factor VII predominantly exists in the form of the inactive single-chain zymogen; however, approximately 1% circulates in the activated form (FVIIa). Activation of factor VII is the initiating event of in vivo coagulation. The ability of factor VIIa to cleave other clotting factors depends on binding to its cofactor tissue factor (TF), which is expressed on the surface of endothelial cells and monocytes in response to injury or inflammation. With formation of the TF/VIIa complex, factor VIIa rapidly activates clotting factors VII, IX, and X, initiating the coagulation cascade.

Factor VII plasma levels are influenced by both environmental and genetic factors. Dietary fat, age, obesity, and sex hormones influence factor VII levels. Five identified allelic polymorphisms also affect plasma levels of factor VII and factor VIIa, with variations of as much as 25-30% in levels of activity and antigen.

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