Familial Bleeding Disorder with a Moderate Thrombocytopenia and Giant Blood Platelets

Among 10 siblings in an otherwise healthy family two sisters had experienced serious bleeding tendency from early childhood. They were moderately thrombocytopenic, their primary bleeding time was prolonged, and splenectomy had been performed in both without effect. One of them, now aged 66, was admitted because of recurrent episodes of life‐threatening gastrointestinal bleedings. The patient had a macrothrom‐bocytic thrombocytopenia, and the ultrastructural appearance of the platelets was abnormal. Her platelets contained decreased amounts of sialic acid, and showed decreased electrophoretic mobility, enhanced aggregation when exposed to ADP and lack of aggregation when tested with ristocetin and a bovine fibrinogen preparation, indicating a membrane defect. No focus for her gastrointestinal bleedings was found. The diagnosis is simple, specific therapy is not available.