Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) thrombotic thrombocytopenic purpura ?
    ### Response:
    Thrombotic thrombocytopenic purpura is a rare disorder that causes blood clots (thrombi) to form in small blood vessels throughout the body. These clots can cause serious medical problems if they block vessels and restrict blood flow to organs such as the brain, kidneys, and heart.
    