A congenital variant of thrombotic thrombocytopenic purpura in two siblings.

We describe two siblings affected by chronic relapsing thrombotic thrombocytopenic purpura from infancy. The elder brother, a 12-year-old boy had 50 such episodes characterized by acute onset of fever, headache, drowsiness, vomiting, dark urine, thrombocytopenia and anemia. The younger sister, a 6-year-old girl, had 8 episodes with the same clinical manifestations. Petechiae and ecchymoses on the extremities were present throughout their lives. Furthermore, anemia with evidence of red blood cell fragmentation and thrombocytopenia were present chronically. Periodical transfusion of frozen fresh plasma prevented recurrent episodes. These cases suggest that there is a congenital variant of thrombotic thrombocytopenic purpura.