Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to Axenfeld-Rieger syndrome ?
    ### Response:
    Axenfeld-Rieger syndrome results from mutations in at least two known genes, PITX2 and FOXC1. PITX2 gene mutations cause type 1, and FOXC1 gene mutations cause type 3. The gene associated with type 2 is likely located on chromosome 13, but it has not been identified.
    