1. Inherited disorders of platelet function
Ali Al Khader, M.D.
Faculty of Medicine
Al-Balqa’ Applied University

2. Introduction The primary hemostatic plug is now formed
Platelets bind via glycoprotein 1b (GpIb) receptors to von Willebrand factor (vWF) on exposed extracellular matrix (ECM)
…then they are activated shape change
granule release
…Released adenosine diphosphate (ADP) and thromboxane A2 (TxA2)
additional platelet aggregation through binding of platelet GpIIb-IIIa
receptors to fibrinogen
The primary hemostatic plug is now formed

3. 3 main groups Defects of adhesion…Bernard-Soulier syndrome
Defects of aggregation…Glanzmann thrombasthenia
Disorders of platelet secretion (release reaction)… = storage pool
disorders

4. Bernard-Soulier syndrome
Defective adhesion of platelets to subendothelial matrix
Caused by an inherited deficiency of the platelet membrane
glycoprotein complex Ib-IX
…this glycoprotein is a receptor for vWF
Often severe bleeding tendency

5. Glanzmann thrombasthenia
Defective platelet aggregation
Autosomal recessive
The platelets fail to aggregate in response to adenosine diphosphate
(ADP), collagen, epinephrine, or thrombin because of deficiency or
dysfunction of glycoprotein IIb-IIIa, an integrin that participates in
“bridge formation” between platelets by binding fibrinogen
Often severe bleeding tendency

6. Disorders of platelet secretion (release reaction)
Defective release of certain mediators of platelet activation, such as thromboxanes and granule-bound ADP

7. Just to remember Uremia is a cause of acquired platelet dysfunction
…It affects platelet adhesion, aggregation & release reaction

8. Thank You