Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Restless Legs Syndrome ?
    ### Response:
    Faulty Use of Iron or Lack of Iron
                
Research suggests that the main cause of restless legs syndrome (RLS) is a faulty use of iron or a lack of iron in the brain. The brain uses iron to make the chemical dopamine (DO-pah-meen) and to control other brain activities.
    