Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) COACH syndrome ?
    ### Response:
    COACH syndrome is a condition that mainly affects the brain and liver.  Most individuals with COACH syndrome have mental retardation, liver problems (fibrosis), and difficulty with movement (ataxia).  Some may also have an abnormality of the eye (called a coloboma) or abnormal eye movements (such as nystagmus).
    