What is the pathophysiology of pediatric factor VII deficiency?

Updated: Jun 22, 2021
  • Author: Helge Dirk Hartung, MD; Chief Editor: Hassan M Yaish, MD  more...
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Answer

Inherited factor VII deficiency can be classified as type 1 or type 2, depending on the absence or presence of factor VII antigen in plasma. [3] Type 1 deficiencies result from decreased biosynthesis or accelerated clearance; type 2 abnormalities represent a dysfunctional molecule. More than 100 mutations, mostly missense mutations, have been identified in the factor VII gene located on chromosome 13. [4] Mutations have been identified throughout the gene, affecting all domains of the transcribed protein, most frequently the catalytic domain.

Correlations between the factor VII genotype, factor VII clotting activity and the clinical phenotype are not tight. Although individuals with the lowest factor VII levels are most likely to be symptomatic, patients with identical mutations may have marked differences in clinical bleeding, suggesting that other factors may contribute to the clinical manifestations of factor VII deficiency. Investigations to determine the contribution by factor VII polymorphisms, other hemostatic proteins, and environmental factors have not yielded specific predictors of bleeding risk. At present, classification based on clinical history (age and type of presentation) rather than on factor VII activity levels has proved to be more useful in predicting future risk of bleeding.


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