A Familial Defect in Platelet Function Associated with Impaired Release of Adenosine Diphosphate

Abstract

Abnormalities of platelet function in some patients with primary, but sporadic, disorders of hemostasis have been attributed to impaired release of platelet adenosine diphosphate (ADP). This defect was detected in six affected members of a family, in association with a slightly prolonged bleeding time. As a consequence, platelet aggregation induced by connective tissue (collagen) and kaolin-induced platelet factor 3 release were impaired, and the second wave of epinephrine-induced aggregation was absent. Primary aggregation by ADP at ambient temperature was normal, but the platelets disaggregated rapidly at 37°C. The platelet defect appears to have been transmitted as an autosomal dominant, with variable expressivity, through three generations. Besides being functionally defective, the platelets were smaller than normal and contained reduced amounts of adenosine triphosphate (ATP) and ADP. A population of prematurely senescent platelets may be present in these patients.