Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Atypical hemolytic uremic syndrome ?
    ### Response:
    Atypical hemolytic-uremic syndrome (aHUS) is a disease that causes abnormal blood clots to form in small blood vessels in the kidneys. These clots can cause serious medical problems if they restrict or block blood flow, including hemolytic anemia, thrombocytopenia, and kidney failure.
    