Thrombocytopathy due to a defect of the platelet membrane complex.

A new type of primary thrombocytopathy is described. Three main alterations were found: (1) a defect of the aggregation reaction with ADP, epinephrine and collagen and a normal response to ristocetin and arachidonic acid; (2) a moderate deficiency of platelet procoagulant activity, and (3) a combined hypertrophy of the two membrane systems of the platelet--the open canalicular and the dense tubular. The latter defect is shown as an abnormal membrane complex situated on one of the platelet poles. This thrombocytopathy is discussed as a new variety of primary platelet disorder.