Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) mucolipidosis type IV ?
    ### Response:
    Mucolipidosis type IV is an inherited disorder characterized by delayed development and vision impairment that worsens over time. The severe form of the disorder is called typical mucolipidosis type IV, and the mild form is called atypical mucolipidosis type IV.
    