Thrombotic thrombocytopenic purpura (TTP) is a rare pediatric disease, yet has grave outcome if not managed
properly. It shares many common clinical features with hemolytic uremic syndrome (HUS). While it is still disputable
whether TTP and HUS are clinically related disorders, recent studies indicate that severe deficiency of a von Willebrand
factor (vWF) cleaving protease is one of the primary causes of TTP. In this discussion, we will focus on TTP in reference
to the deficiency of this protease, with the objective of increasing awareness among pediatric healthcare professionals of
this less commonly recognized disease.