Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.
Tissue Factor Pathway Inhibitor (TFPI) is a serine protease inhibitor of the Factor VIIa/Tissue Factor (FVIIa/TF)-initiated clotting cascade. Mice expressing a mutant form of TFPI, in which its Kunitz–1 domain has been deleted (TFPIKu1δ/δ), die prematurely in embryogenesis between E9.5dpc and birth. These results provide a rationale for the absence of TFPI-deficient patients. This early mortality can be ameliorated by an accompanying heterozygous or homozygous deficiency in FVII. Thus, diminishment of FVII activity precludes the requirement for TFPI-mediated inhibition of the FVIIa/TF pathway during embryogenesis.