Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to combined pituitary hormone deficiency ?
    ### Response:
    Mutations in at least eight genes have been found to cause combined pituitary hormone deficiency. Mutations in the PROP1 gene are the most common known cause of this disorder, accounting for an estimated 12 to 55 percent of cases. Mutations in other genes have each been identified in a smaller number of affected individuals.
    