Two cases of type II thrombasthenia (TA) were presented and investigated with special reference to the platelet-membrane glycoprotein abnormalities.
They were a 15-yr-old girl and a 33-yr-old woman suffering from bleeding tendeucy such as easy bruising, epistaxis and menorrhagia from infancy. They had quite similar platelet function abnormalities characterized by a markedly prolonged bleeding time without thrombocytopenia, and absent aggregation responses to ADP and other physiologic stimulating agents except for ristocetin or bovine factor VIII. Clot retraction and the interaction between platelets and polymerizing fibrin were normal. Tests of coaqulation/fibrinolysis were all normal. These results indicated that they were type II TA.
Analysis of platelet-membrane glycoproteins by one- or two-dimensional SDS-polyacrylamide gel electrophoresis revealed the corresponding abnormalities with type II TA, that is, not defective but decreased amounts of glycoprotein IIb and III (IIIa).
