Thrombotic thrombocytopenic purpura in a newborn.

This report describes a newborn who presented with hyperbilirubinemia and thrombocytopenia. The patient recovered after treatment with antibiotics, phototherapy, and a platelet transfusion. Analysis of the plasma von Willebrand factor-cleaving metalloprotease, ADAMTS13, revealed low protease activity in the patient and her two siblings, and a mild deficiency in both parents. These results confirmed the clinical suspicion of hereditary thrombotic thrombocytopenic purpura (TTP). Although most cases of thrombocytopenia and hyperbilirubinemia in the newborn period are caused by other causes, genetic deficiency of ADAMTS13 may not be as uncommon as previously believed. Early diagnosis may have important implications for the patients.