Coagulation
Hereditary bleeding disorders
Prekallikrein deficiency

Authors: Kendall Crookston, M.D., Ph.D., Lizabeth Rosenbaum, M.D. and Julie Gober-Wilcox, M.D. (see Authors page)

Revised: 28 April 2016, last major update October 2010

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PubMed Search: Prekallikrein deficiency

Cite this page: Prekallikrein deficiency . PathologyOutlines.com website. http://pathologyoutlines.com/topic/coagulationprekallikreindef.html. Accessed February 26th, 2017.
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
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
Treatment
  • Typically not required
Differential Diagnosis