<prompt> Glanzmann thrombasthenia is due to defect inGp Ib-IXGp IIbIIIaCD68Von Willebrand factor  <response>: Platelet Function Defects:- Defect in platelet adhesion:- Bernard Soulier syndrome,Von Willebrands disease Defect in platelet aggregation:- Glanzmann thrombasthenia, Afbrinogenemia Defect in platelet secretion:- Storage pool disorders,drugs NSAID induced Glanzmann thrombasthenia is due to defective platelet aggregation, due to defect in receptor Gp IIb-IIIa Bernard Soulier syndrome is due to defective platelet adhesion due to defect in Gp Ib-IX In the image shown above, agglutination is seen with theristocetin. There is no aggregation with ADP, adrenaline or collagen. Possible diagnosis:- Glanzmanns thrombasthenia or afibrinogenaemia In the image above, there is lack of agglutination with ristocetin, but agglutination occurs with other agonists. Possible diagnosis:- Von Willebrand Disease vWD or Bernard Soulier Syndrome BSS. vWD is differentiated from BSS by repeating the platelet aggregometry after adding cryoprecipitate. After adding cryoprecipitate which contains von Willebrand factor, agglutination occurs with ristocetin.Then a diagnosis of vWD can be made. BSS - Disorder of platelet adhesion, due to defect in Ib-IX receptor Glanzmann thrombasthenia - Disorder of platelet aggregatation, due to defect in IIb-IIIa receptor. Glanzmanns thrombasthenia GT is an autosomal recessive inherited platelet function defect characterized by normal platelet count, prolonged bleeding time and abnormal clot retraction. Clot retraction test is a measurement of platelet function. Clot retraction test is abnormal in thrombocytopenia, thrombasthenia and polycythemia Ref:- Robbins Basic Pathology 9th Edition; Pg num:- 660 