Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) isolated Pierre Robin sequence ?
    ### Response:
    Pierre Robin sequence is a set of abnormalities affecting the head and face, consisting of a small lower jaw (micrognathia), a tongue that is placed further back than normal (glossoptosis), and an opening in the roof of the mouth (a cleft palate). This condition is described as a "sequence" because one of its features, an underdeveloped lower jaw (mandible), sets off a sequence of events before birth that cause the other signs and symptoms.
    