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Rare Platelet Disorders


There exist a number of rare platelet bleeding disorders. People with these rare disorders will find specialized treatment at an HTC under the care of a hematologist. 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.

There’s much we don’t know about platelet disorders. In some cases, patients may only know they have an "unspecified" platelet disorder.

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 specific problem may result in rare platelet disorders, such as:

  • 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 from even a small cut
    • Laboratory tests are needed to diagnose BSS. Some people with BSS have only slightly lower-than-normal platelet counts. Interestingly, under a microscope, the platelets of people with BSS are much larger than normal
  • 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
    • Laboratory tests are necessary to diagnose GT. In people with GT, the platelet count is normal. Under a microscope, their platelets are normal in size and shape. Blood tests are available to check for deficiency of glycoprotein IIb/IIIa in the platelets
  • 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. Blood tests are needed to diagnose SPD