HP and congenital thrombotic thrombocytopenic purpura: At the time of diagnosis of TMA, all patients presented with evidence of microangiopathic hemolytic anemia (detection of schistocytes in the peripheral blood, increased LDH, substantial reduction of serum haptoglobin, and decreased platelet counts) and all developed severe renal dysfunction (median eGFR at the diagnosis of TMA was 20.5 mL/min/1.73 m2, range 3–53 mL/min/1.73 m2).