Thrombocytopenia and severe hyperbilirubinemia in the neonatal period secondary to congenital thrombotic thrombocytopenic purpura and ADAMTS13 deficiency.

Congenital thrombotic thrombocytopenic purpura (TTP) is an inherited form of TTP due to the deficiency of von Willebrand factor (vWF) cleaving protease ADAMTS13. The authors describe two children with congenital TTP who presented with thrombocytopenia, hemolytic anemia, elevated LDH levels, and schistocytes on peripheral blood smear. In both children, the diagnosis of the disease was delayed despite neonatal histories significant for thrombocytopenia, anemia, and severe hyperbilirubinemia. Severely decreased ADAMTS13 activity (<0.1 U/mL), the absence of an inhibitor to the protease, and partial deficiency found in the parents confirmed the diagnosis of congenital TTP. The authors suggest that congenital TTP should be considered in the differential diagnosis for newborns presenting with severe hyperbilirubinemia, anemia, and thrombocytopenia.