Quebec platelet disorder


Quebec Platelet Disorder is a rare, autosomal dominant bleeding disorder described in a family from the province of Quebec in Canada.

Presentation

Individuals with QPD are at risk for experiencing a number of bleeding symptoms, including joint bleeds, hematuria, and large bruising. In 2010, the genetic cause of QPD has been determined as a mutation involving an extra copy of the uPA gene The mutation causes overproduction of an enzyme that accelerates blood clot breakdown.

Pathophysiology

The disorder is characterized by large amounts of the fibrinolytic enzyme urokinase-type plasminogen activator in platelets. Consequently, stored platelet plasminogen is converted to plasmin, which is thought to play a role in degrading a number of proteins stored in platelet α-granules. These proteins include platelet factor V, Von Willebrand factor, fibrinogen, thrombospondin-1, and osteonectin. There is also a quantitative deficiency in the platelet protein multimerin 1. Furthermore, upon QPD platelet activation, u-PA can be released into forming clots and accelerate clot lysis, resulting in delayed-onset bleeding.

Diagnosis

Treatment

History

The discovery was found by a team of doctors at McMaster University, led by Dr. Catherine Hayward, a hematologist.