Overview

Platelet aggregation at sites of vascular injury is essential for the formation of the primary haemostatic plug. The mechanism of platelet aggregation under conditions of physiological flow is a complex multistep process, which requires the synergistic action of several different platelet receptors.1 Platelet aggregation disorders are conditions in which the platelets do not work the way they should.

Glanzmann thrombasthenia is an inherited platelet function disorder caused by an abnormality in the receptor for fibrinogen (also called the GpIIb/IIIa receptor). Receptors are proteins on the surface of the platelets that help the platelet interact with, and respond to, other blood cells or substances. Since the fibrinogen receptor is absent or does not work properly, the platelets do not stick to each other at the site of injury and it is difficult for the normal blood clot to form.2

Symptoms

This disorder causes moderate to severe bleeding symptoms:

• Bleeding from the mouth
• Bleeding with dental procedures
• Nose bleeds
• Bruising or small purplish red dots under the skin
• Bleeding for a long time after an injury or surgery
• Girls or women may have heavy periods
• Infant boys may have bleeding after circumcision3

Causes

Glanzmann thrombasthenia is an autosomal recessive disorder, meaning that both parents carry a genetic change (even though they themselves do not usually have the disorder), and pass this changed gene on to their child. Like many autosomal recessive disorders, it may be more frequent in areas of the world where marriage between relatives is more common. Glanzmann thrombasthenia affects both males and females.2