Congenital Thrombocytopenia with Giant Platelets: a Defect in the Platelet Membrane

Summary: Three patients with congenital macrothrombocytic thrombocytopenia are described. The platelets had a reduced electrophoretic mobility, and the content of sialic acid was also abnormally low, suggesting a defect in the platelet membrane. Platelets were rapidly removed from the circulation, possibly because the platelet membrane defect was associated with reduced electrostatic repulsive forces.