Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to Cowden syndrome ?
    ### Response:
    Changes involving at least four genes, PTEN, SDHB, SDHD, and KLLN, have been identified in people with Cowden syndrome or Cowden-like syndrome.  Most cases of Cowden syndrome and a small percentage of cases of Cowden-like syndrome result from mutations in the PTEN gene.
    