Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Fumarase deficiency ?
    ### Response:
    Fumarase deficiency is an inherited condition that primarily affects the nervous system, especially the brain. Affected infants may have microcephaly, abnormal brain structure, severe developmental delay, weak muscle tone (hypotonia), failure to thrive, seizures, and/or distinctive facial features.
    