Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Wolfram syndrome ?
    ### Response:
    What causes Wolfram syndrome? There are two types of Wolfram syndrome (type 1 and type 2) which are primarily differentiated by their genetic cause. Changes (mutations) in the WFS1 gene are responsible for approximately 90% of Wolfram syndrome type 1 cases.
    