Diagnosis of Scott syndrome in patient with bleeding disorder of unknown cause.

Scott syndrome is a rare bleeding disorder due to an impaired exposure of phosphatidilserine on the platelet membrane, compromising the platelet procoagulant activity, thrombin generation and, thus, the clot formation. We report a case of a 17-year-old female adolescent with bleeding episodes of unknown cause. She had normal coagulation, but altered platelet aggregation under arteriolar flow, indicating platelet dysfunction. Furthermore, the expression of Annexin V was markedly reduced and the diagnosis of Scott syndrome was established. She was treated with platelet transfusions and demonstrated a clinical improvement. Scott syndrome may be investigated in cases with bleeding history and normal coagulation tests.