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.

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 blood clotting. 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 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.

This condition is inherited in an autosomal recessive pattern, 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.

Published Date: July 01, 2014
Published By: National Institutes of Health