Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Joubert syndrome ?
    ### Response:
    Joubert syndrome is disorder of abnormal brain development that may affect many parts of the body. It is characterized by the absence or underdevelopment of the cerebellar vermis (a part of the brain that controls balance and coordination) and a malformed brain stem (connection between the brain and spinal cord).
    