Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the symptoms of Ankylosing spondylitis ?
    ### Response:
    What are the signs and symptoms of Ankylosing spondylitis? Ankylosing spondylitis (AS) primarily affects the spine, but may affect other parts of the body too. Signs and symptoms usually begin in adolescence or early adulthood and include back pain and stiffness.
    