Glanzmann Thrombasthenia (GT) is a rare platelet disorder characterised by excessive bleeding even though patients may have normal platelet counts. It is an inherited autosomal recessive disorder which results in qualitative and quantitative defects in the platelet membrane glycoprotein GPIIb/IIIa.

GPIIb/IIIa is a heterodimeric glycoprotein which acts the th3e receptor for fibrinogen. Activation of platelets causes a conformational change in GPIIb/IIIa which allow fibrinogen and other adhesion molecules, including von Willibrand factor to bind. This is an important step platelet aggregation and fibrin clot formation. Patients who have defective or deficient GPIIb/IIIa have deduced capacity for clot formation and which leads to the excessive bleeding.

Laboratory tests for diagnosis of GT is a platelets flowcytometric test for expression of GPIIb/IIIa.

Management of GT patients involves both preventive measures and treatment of specific bleeding episodes. Preventative measures include avoidance of antiplatelet agents such as aspirin and other anti-inflammatory drugs (NSAIDs) and hormonal contraceptives to control excessive menstrual bleeding.

Severe bleeding is treated with platelet transfusion and/or Recombinant factor VIIa (rFVIIa). Transfusion is also indicated as cover for surgical procedures. Iron or folate supplements may be indicated if bleeding results in anaemia. As GT patients are likely to be on life long transfusion support, use of ABO, HLA and Kell blood group matched platelets is indicated to avoid alloimmunisation which makes it difficult to find compatible platelets in the future. HLA matched platelets should be used for such patients even if not currently sensitised. Regular transfusion does carry risks including TRALI, blood borne pathogens and other transfusion reactions.

Post transfusion patients can be tested for HLA and GPIIb/IIIa antibodies. A travelling control bled on the same day is usually included in the test.

In cases of persistent and recurrent life-threatening bleeding which are refractory to  current treatment, HSCT may be a clinical option. Gene therapy is currently experimental in this group of patients.