Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to ankylosing spondylitis ?
    ### Response:
    Ankylosing spondylitis is likely caused by a combination of genetic and environmental factors, most of which have not been identified. However, researchers have found variations in several genes that influence the risk of developing this disorder.  The HLA-B gene provides instructions for making a protein that plays an important role in the immune system.
    