Inherited heterogenous defect in platelet aggregation selectively with ADP and epinephrine--a series of 25 cases

Inherited heterogeneous defects of platelet function caused by impairment of platelet responses to weak agonists as ADP, epinephrine and others as low concentration collagen and platelet activating factor (PAF) have been described, though quite rarely. We describe here 25 cases of this defect with impairment in response to ADP and epinephrine. Subjects with a history of generalized bleeding and a prolonged bleeding time, PF3 availability or prothrombin consumption index and a normal platelet count, prothrombin time, activated partial thromboplastin time and clot solubility were subjected to platelet aggregation. Those of these which showed a normal aggregation with collagen and arachidonic acid and an absent or reduced aggregation with ADP and epinephrine were included in our study group. Subjects with history or findings suggestive of antiplatelet drug intake or any acquired condition affecting platelet functions were excluded from this study. 76% of the patients had onset of recurrent bleeding manifestations since childhood with a mean age at onset of 9.2 years. A positive family history was present in 36% of the patients. Majority of the patients (88%) presented with mild bleeding manifestations, the commonest symptom being appearance of recurrent ecchymotic spots. We present here a series of patients with a hereditary platelet aggregation defect selectively with ADP and epinephrine.