Is prekallikrein deficiency linked to an increased risk of blood clots?

Current evidence does not show a clear association between prekallikrein deficiency and thrombosis. Some case reports mention clotting events, but these are usually attributable to other risk factors such as age, immobility, or underlying cardiovascular disease. Regular cardiovascular risk assessment remains important.

Does a prolonged activated partial thromboplastin time (PTT) mean I will bleed more during surgery?

prolonged PTT in prekallikrein deficiency is usually an incidental laboratory finding and does not correlate with an increased bleeding risk. Most patients undergo surgery without special precautions beyond standard peri‑operative care. However, if you have a history of bleeding or are taking anticoagulants, your surgeon may review your coagulation profile and consider additional monitoring or prophylactic measures.

What special precautions should I take if I have prekallikrein deficiency?

There is no specific medication or diet required for prekallikrein deficiency alone. Avoid medications that can prolong clotting time (e.g., certain NSAIDs) if you have other bleeding risk factors. Inform all healthcare providers of your condition, especially before invasive procedures, so they can interpret your lab results correctly.

How is prekallikrein deficiency diagnosed and confirmed?

Initial screening is a prolonged PTT on routine coagulation testing. Confirmation requires a specific assay for prekallikrein activity or a plasma kallikrein activity test, followed by genetic testing for mutations in the KLKB1 gene. A qualified hematologist can order these specialized tests.

Prekallikrein deficiency

Prekallikrein deficiency is a rare blood condition that usually causes no health problems despite a prolonged activated partial thromboplastin time (PTT) on laboratory testing.

Overview

Prekallikrein deficiency is a blood condition that usually causes no health problems. In people with this condition, blood tests show a prolonged activated partial thromboplastin time (PTT), a result that is typically associated with bleeding problems; however, bleeding problems generally do not occur in prekallikrein deficiency. The condition is usually discovered when blood tests are done for other reasons.

A few people with prekallikrein deficiency have experienced health problems related to such as heart attack, stroke, a clot in the deep veins of the arms or legs (), nosebleeds, or excessive bleeding after surgery. However, these are common problems in the general population, and most affected individuals have other risk factors for developing them, so it is unclear whether their occurrence is related to prekallikrein deficiency.

Frequency

The prevalence of prekallikrein deficiency is unknown. Approximately 80 affected individuals in about 30 families have been described in the medical literature. Because prekallikrein deficiency usually does not cause any symptoms, researchers suspect that most people with the condition are never diagnosed.

Causes

Prekallikrein deficiency is caused by mutations in the KLKB1 gene, which provides instructions for making a protein called prekallikrein. This protein, when converted to an active form called plasma kallikrein in the blood, is involved in the early stages of . Plasma kallikrein plays a role in a process called the intrinsic coagulation pathway (also called the contact activation pathway). This pathway turns on (activates) proteins that are needed later in the clotting process. Blood clots protect the body after an injury by sealing off damaged blood vessels and preventing further blood loss.

The KLKB1 gene mutations that cause prekallikrein deficiency reduce or eliminate functional plasma kallikrein, which likely impairs the intrinsic coagulation pathway. Researchers suggest that this lack (deficiency) of functional plasma kallikrein protein does not generally cause any symptoms because another process called the extrinsic coagulation pathway (also known as the tissue factor pathway) can compensate for the impaired intrinsic coagulation pathway.

Learn more about the gene associated with Prekallikrein deficiency

KLKB1

Inheritance

This condition is inherited in an , which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Other Names for This Condition

Congenital prekallikrein deficiency
Fletcher factor deficiency
Fletcher trait
PKK deficiency

Additional Information & Resources

Genetic Testing Information

Genetic Testing Registry: Prekallikrein deficiency

Genetic and Rare Diseases Information Center

Congenital prekallikrein deficiency

Patient Support and Advocacy Resources

National Organization for Rare Disorders (NORD)

Catalog of Genes and Diseases from OMIM

PREKALLIKREIN DEFICIENCY; PKKD

Scientific Articles on PubMed

PubMed

References

Francois D, Trigui N, Leterreux G, Flaujac C, Horellou MH, Mazaux L, Vignon D, Conard J, de Mazancourt P. Severe prekallikrein deficiencies due to homozygous C529Y mutations. Blood Coagul Fibrinolysis. 2007 Apr;18(3):283-6. doi: 10.1097/MBC.0b013e328010bcde. Citation on PubMed
Girolami A, Allemand E, Bertozzi I, Candeo N, Marun S, Girolami B. Thrombotic events in patients with congenital prekallikrein deficiency: a critical evaluation of all reported cases. Acta Haematol. 2010;123(4):210-4. doi: 10.1159/000313361. Epub 2010 Apr 27. Citation on PubMed
Girolami A, Scarparo P, Candeo N, Lombardi AM. Congenital prekallikrein deficiency. Expert Rev Hematol. 2010 Dec;3(6):685-95. doi: 10.1586/ehm.10.69. Citation on PubMed
Nakao T, Yamane T, Katagami T, Shiota M, Izumi Y, Samori T, Hino M, Iwao H. Severe prekallikrein deficiency due to a homozygous Trp499Stop nonsense mutation. Blood Coagul Fibrinolysis. 2011 Jun;22(4):337-9. doi: 10.1097/MBC.0b013e3283444ddb. Citation on PubMed
Quail MT. Prekallikrein deficiency. J Pediatr Oncol Nurs. 2013 Jul-Aug;30(4):198-204. doi: 10.1177/1043454213487436. Epub 2013 Apr 29. Citation on PubMed
Wynne Jones D, Russell G, Allford SL, Burdon K, Hawkins GA, Bowden DW, Minaee S, Mumford AD. Severe prekallikrein deficiency associated with homozygosity for an Arg94Stop nonsense mutation. Br J Haematol. 2004 Oct;127(2):220-3. doi: 10.1111/j.1365-2141.2004.05180.x. Citation on PubMed