Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Niemann-Pick disease ?
    ### Response:
    Niemann-Pick disease is a condition that affects many body systems. It has a wide range of symptoms that vary in severity. Niemann-Pick disease is divided into four main types: type A, type B, type C1, and type C2. These types are classified on the basis of genetic cause and the signs and symptoms of the condition.
    