What is factor VII deficiency?

Updated: Oct 28, 2019
  • Author: Muhammad A Mir, MD, FACP; Chief Editor: Perumal Thiagarajan, MD  more...
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Answer

Answer

Factor VII is a vitamin K–dependent glycoprotein essential to the extrinsic pathway of coagulation. Deficiencies may be inherited as an autosomal recessive characteristic or acquired in association with vitamin K deficiency, sepsis, autoantibodies, and inhibitors. [93, 94] The prevalence of congenital deficiency is low, with only 729 individual cases.(involving 221 unique variants) in the factor VII gene described in the Factor VII Gene (F7) Variant Database as of 2019. [95]

The predisposition to bleeding is variable and to some extent depends on the amount of plasma factor VII activity, although this correlation is poor. [96] In congenital factor VII deficiency, the clinical picture is related to the levels of factor VII coagulant activity. Menorrhagia and metrorrhagia in females and mucosal bleeding and hemarthrosis in both sexes are the most frequent manifestations. Individuals homozygous for the mutation who have complete absence of factor VII activity in plasma usually die shortly after birth because of severe hemorrhage.

This defect produces prolonged PT, reduced factor VII activity, and normal aPTT. [97] True deficiencies are characterized by very low factor VII activity and low factor VII antigen. Other patients may have normal antigen levels but low activity. [98]

Clinical symptoms and factor VII activity levels in plasma correlate rather poorly. Patients may have prolonged PTs and a mixing study is helpful as rapid, sustained correction suggests a factor VII deficiency, but the final diagnosis is established by quantitative factor VII assays. Treatment consists of factor replacement with FFP, prothrombin complex concentrates, or factor VII concentrates. RFVIIa is a very useful alternative. Hunault and Bauer have reported several successfully treated patients. [96] Because of the short half-life of factor VIIa, repeated doses must be administered.


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