Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) piebaldism ?
    ### Response:
    Piebaldism is a condition characterized by the absence of cells called melanocytes in certain areas of the skin and hair. Melanocytes produce the pigment melanin, which contributes to hair, eye, and skin color. The absence of melanocytes leads to patches of skin and hair that are lighter than normal.
    