Rare Platelet Disorders

There exists a number of rare platelet bleeding disorders. Rare platelet disorders may be inherited or acquired after birth. These disorders can last a short time or be a chronic condition. On the positive side, platelet disorders are usually milder than the other types of bleeding disorders.

Platelets are tiny, irregularly shaped blood cell pieces (called fragments) that play an important role in clotting blood. When an injury occurs and a blood clot is needed, the platelets become sticky and help plug the site of the injury. They attract other proteins needed in the clotting process and they help form a stable clot. There are several ways or reasons that platelets may not work properly. The rare platelet disorders that can cause problems include:

  • Bernard-Soulier Syndrome (BSS): a very rare platelet disorder that causes a deficiency of glycoprotein lb, the receptor for vWF, which is important in clot formation. A person with BSS can bleed for a very long time before a clot forms. In fact, it may take more than 20 minutes for the bleeding to stop even a small cut.


  • Glanzmann’s Thrombasthenia (GT): an extremely rare bleeding disorder in which the platelets lack glycoprotein IIb/IIIa, the binding sites for vWF, on the surface. In people with GT, platelets do not adhere or stick to each other as they should. Bleeding continues significantly longer than normal.


  • Platelet Storage Pool Disease (SPD): a name given to several rare disorders in which the platelet granules are affected. During the process of making a platelet plug, the platelets change shape. Chemicals inside the granules are pushed out (called secretion) into the bloodstream, signaling other platelets to the plug. In SPD, a certain type of granule in the platelets may be missing or be abnormal. The result: the body takes longer to form a clot. SPD usually causes mild to moderate bleeding.