Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Bardet-Biedl syndrome ?
    ### Response:
    Bardet-Biedl syndrome is a disorder that affects many parts of the body. The signs and symptoms of this condition vary among affected individuals, even among members of the same family.  Vision loss is one of the major features of Bardet-Biedl syndrome. Loss of vision occurs as the light-sensing tissue at the back of the eye (the retina) gradually deteriorates.
    