Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Niemann-Pick disease type A ?
    ### Response:
    Niemann-Pick disease is an inherited condition involving lipid metabolism, which is the breakdown, transport, and use of fats and cholesterol in the body. In people with this condition, abnormal lipid metabolism causes harmful amounts of lipids to accumulate in the spleen, liver, lungs, bone marrow, and brain.
    