Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Chorea ?
    ### Response:
    Chorea is an abnormal involuntary movement disorder, one of a group of neurological disorders called dyskinesias, which are caused by overactivity of the neurotransmitter dopamine in the areas of the brain that control movement. Chorea is characterized by brief, irregular contractions that are not repetitive or rhythmic, but appear to flow from one muscle to the next.
    