Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Fibromuscular dysplasia ?
    ### Response:
    Fibromuscular dysplasia (FMD) is the abnormal development or growth of cells in the walls of arteries that can cause the vessels to narrow or bulge. The carotid arteries, which pass through the neck and supply blood to the brain, are commonly affected. Arteries within the brain and kidneys can also be affected.
    