Platelet Disorders

Causes of inherited platelet function disorders

• Severe disorders of platelet function: Wiskott-Aldrich syndrome (WAS), Glanzmann's thrombasthenia (GT), Bernard-Soulier syndrome (BSS).
• Disorders of receptors and signal transduction: platelet cyclo-oxygenase deficiency, thromboxane synthase deficiency, thromboxane A2 receptor defect, ADP receptor defect.
• Disorders of platelet adhesion: von Willebrand's disease (vWD).
• Disorders of the platelet granules: idiopathic dense-granule disorder (d-storage pool disease), Hermansky-Pudlak syndrome, Chediak-Higashi syndrome, grey platelet syndrome (GPS), Paris-Trousseau/Jacobsen syndrome.
• Idiopathic alpha- and dense-granule storage pool disease.
• Disorders of phospholipid exposure; Scott syndrome

Von Willebrand's disease (vWD) - this is inherited as an autosomal dominant condition. There is deficient or defective production of vWF. This protein mediates platelet adhesion to the endothelium and protects factor VIII from degradation. There are a couple of well recognised variations. See separate article Von Willebrand's Disease.

Bernard-Soulier syndrome (BSS) - this is a deficiency of platelet glycoprotein Ib which mediates the early action of platelets on the subendothelial surface via the von Willebrand protein. It is a rare but severe bleeding disorder. The platelets are large. They may be as big as red blood cells and may be missed because most automatic counters do not count them as platelets.[4] See separate article Bernard-Soulier Syndrome.

Glanzmann's thrombasthenia (GT) - this results from a deficiency of the glycoprotein IIb/IIIa complex. Platelets fail to aggregate. The more severe type I results from a complete absence of the glycoprotein IIb/IIIa complex, while in the milder type II, some of the glycoprotein IIb/IIIa complex is retained. Both GT and BSS respond to platelet transfusion but this should be reserved for severe problems, as alloantibodies may form.

Grey platelet syndrome (GPS) - this is a rare autosomal recessive disorder with large platelets that appear grey. It is also called platelet alpha granule deficiency.[6]See separate article Grey Platelet Syndrome.

Congenital disorders of thromboxane and ADP metabolism - thromboxane and ADP play an important role in haemostasis. It is this pathway that is impaired by aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs). Congenital disorders of this pathway have been described.

A bone marrow or cord blood transplant is a process to replace unhealthy bone marrow with healthy bone marrow. Bone marrow transplants can be used to treat patients with:

• life-threatening blood cancers like leukemia
•diseases which result in bone marrow failure like aplastic anemia
• other immune system or genetic diseases

Research on transplant has led to improved survival rates over time, which has led to more patients being helped by this treatment. For many diseases, bone marrow transplant is the only cure at this time.