Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Hajdu-Cheney syndrome ?
    ### Response:
    Hajdu-Cheney syndrome is a rare disorder that can affect many parts of the body, particularly the bones. Loss of bone tissue from the hands and feet (acro-osteolysis) is a characteristic feature of the condition. The fingers and toes are short and broad, and they may become shorter over time as bone at the tips continues to break down.
    