Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Idiopathic inflammatory myopathy ?
    ### Response:
    Idiopathic inflammatory myopathy refers to a group of conditions that affect the skeletal muscles (muscles used for movement). Although the condition can be diagnosed at any age, idiopathic inflammatory myopathy most commonly occurs in adults between ages 40 and 60 years or in children between ages 5 and 15 years.
    