Home   Chapter Home   Jobs   Conferences   Fellowships   Books



Advertisement

Coagulation

Hereditary bleeding disorders

Prekallekrein deficiency


Reviewers: Kendall Crookston, M.D., Ph.D., University of New Mexico; Lizabeth Rosenbaum, MD, University of New Mexico; Julie Gober-Wilcox, M.D., Resident, University of New Mexico (see Reviewers page)
Revised: 21 November 2010, last major update October 2010
Copyright: (c) 2002-2010, PathologyOutlines.com, Inc.

Definition / General
=========================================================================

● Prekallikrein deficiency is a rare congenital disorder that causes an isolated prolonged PTT but is not associated with a bleeding tendency

Terminology
=========================================================================

● Also known as Fletcher factor deficiency

Epidemiology
=========================================================================

● Rare

Pathophysiology
=========================================================================

● Prekallikrein is a contact factor that complexes with high molecular weight kininogen and is cleaved by factor XII (Hageman factor) to produce kallikrein in the initial steps of the intrinsic pathway

Coagulation cascade

Etiology
=========================================================================

● Autosomal recessive inheritance
● Homozygous individuals have <1% activity
● Heterozygous individuals have 20%-60% of normal activity
● There are rare variants of abnormal prekallikrein molecules

Clinical features
=========================================================================

● No bleeding tendency
● Usually detected in asymptomatic individuals after the incidental finding of isolated prolonged PTT
● There have been anecdotal reports of prekallikrein deficiency and increased risk of arterial and venous thrombosis, but usually thrombotic risk factors were identified (Acta Haematol 2010;123:210)

Laboratory
=========================================================================

● Prolonged PTT that corrects after mixing study
● Normal PT, thrombin time and bleeding time
● Specific functional prekallikrein assay is diagnostic

Case reports
=========================================================================

● Prekallikrein deficiency resulting in mucosal hemorrhage (Am J Med Sci 2009;338:429)

Treatment
=========================================================================

● Typically not required

Differential diagnosis
=========================================================================

Factor XII deficiency
High molecular weight kininogen deficiency
● Acquired prekallikrein deficiency due to DIC or liver disease, rarely due to antibodies to prekallikrein

Additional references
=========================================================================

Consultative Hemostasis and Thrombosis (2007)

End of Coagulation > Hereditary bleeding disorders > Prekallekrein deficiency


This information is intended for physicians and related personnel, who understand that medical information is often imperfect, and must be interpreted in the context of a patient's clinical data using reasonable medical judgment. This website should not be used as a substitute for the advice of a licensed physician.

All information on this website is protected by copyright of PathologyOutlines.com, Inc. Information from third parties may also be protected by copyright. Please contact us at copyrightPathOut@gmail.com with any questions (click here for other contact information).