Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to FG syndrome ?
    ### Response:
    Researchers have identified changes in five regions of the X chromosome that are linked to FG syndrome in affected families. Mutations in a gene called MED12, which is located in one of these regions, appear to be the most common cause of the disorder. Researchers are investigating genes in other regions of the X chromosome that may also be associated with FG syndrome.
    