Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to citrullinemia ?
    ### Response:
    Mutations in the ASS1 and SLC25A13 genes cause citrullinemia.  Citrullinemia belongs to a class of genetic diseases called urea cycle disorders. The urea cycle is a sequence of chemical reactions that takes place in liver cells. These reactions process excess nitrogen that is generated when protein is used by the body.
    