Glanzmann's thrombasthenia is an abnormality of the platelets.[2] It is an extremely rare coagulopathy (bleeding disorder due to a blood abnormality), in which the platelets contain defective or low levels of glycoprotein IIb/IIIa (GpIIb/IIIa), which is a receptor for fibrinogen. As a result, no fibrinogen bridging of platelets to other platelets can occur, and the bleeding time is significantly prolonged.
The bleeding tendency in Glanzmann's thrombasthenia is variable,[3] some individuals having minimal bruising, while others have frequent, severe, potentially fatal hemorrhages. Moreover, platelet αIIbβ3 levels correlate poorly with hemorrhagic severity, as virtually undetectable αIIbβ3 levels can correlate with negligible bleeding symptoms, and 10%–15% levels can correlate with severe bleeding.[6] Unidentified factors other than the platelet defect itself may have important roles.[3]
Light transmission aggregometry is widely accepted as the gold standard diagnostic tool for assessing platelet function, and a result of absent aggregation with any agonist except ristocetin is highly specific for Glanzmann's thrombasthenia.[9] Following is a table comparing its result with other platelet aggregation disorders:
The subsequent studies, following Eduard Glanzmann's description of hemorrhagic symptoms and "weak platelets", demonstrated that these patients have prolonged bleeding times and their platelets failed to aggregate in response to activation. In the mid-1970s, Nurden and Caen[15] and Phillips and colleagues[16] discovered that thrombasthenic platelets are deficient in integrins αIIbβ3.
^Tholouli E, Hay CR, O'Gorman P, Makris M (2004). "Acquired Glanzmann's thrombasthenia without thrombocytopenia: a severe acquired autoimmune bleeding disorder". Br. J. Haematol. 127 (2): 209–13. doi:10.1111/j.1365-2141.2004.05173.x. PMID15461628. S2CID33436277.
^Glanzmann, WE (1918). "Hereditäre hämorrhagische Thrombasthenie. Ein Beitrag zur Pathologie der Blutplättchen.[Hereditary haemorrhagic thrombasthenia. A contribution to the pathology of platelets] (German)". Jahrbuch für Kinderheilkunde [Yearbook of Pediatrics]. 88 (1–42): 113–141.