Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Hereditary fructose intolerance ?
    ### Response:
    Hereditary fructose intolerance (HFI) is a metabolic disease caused by the absence of an enzyme called aldolase B. In people with HFI, ingestion of fructose (fruit sugar) and sucrose (cane or beet sugar, table sugar) causes severe hypoglycemia (low blood sugar) and the build up of dangerous substances in the liver.
    