Hereditary bleeding disorders

High molecular weight kininogen deficiency / assay

Last author update: 1 July 2011
Last staff update: 22 September 2020

Copyright: 2002-2024,, Inc.

PubMed Search: High molecular weight kininogen deficiency/assay

Julie Kim Harrington, M.D.
Jeremy C. Parsons, M.D.
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Cite this page: Crookston K, Rosenbaum LS, Gober-Wilcox J. High molecular weight kininogen deficiency / assay. website. Accessed February 23rd, 2024.
Definition / general
  • High molecular weight kininogen deficiency is a rare congenital disorder inherited as an autosomal recessive trait, not associated with a bleeding diathesis
  • Typically discovered in individuals with an isolated prolonged PTT
  • High molecular weight kininogen is also known as Fitzgerald factor, Williams factor and Flaujeac factor
  • High molecular weight kininogen is a protein produced by the liver (with no inherent catalytic activity) that is involved in the early steps of the intrinsic coagulation pathway; it functions as a cofactor and binds with prekallikrein and factor XI to help facilitate their activation by factor XIIa
  • The kininogens (low and high molecular weight) are also involved in the kinin-kallikrein system and function to inhibit thrombin activation of platelets and stimulate liberation of nitric oxide, prostacyclin and tissue plasminogen activator
Clinical features
  • Not associated with bleeding
  • Isolated prolonged PTT
  • Negative lupus anticoagulant
  • Specific assay to test for deficiency uses high molecular weight kininogen deficient plasma mixed with patient plasma; a PTT is performed and is compared to a standard curve of high molecular weight kininogen vs. PTT
  • Interference occurs in these assays if patient is on heparin, hirudin or argatroban, possibly danaparoid
  • Lower levels in newborns, increase to adult levels by age 6 months
Case reports
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