Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Pityriasis rubra pilaris ?
    ### Response:
    What causes pityriasis rubra pilaris? In most cases, pityriasis rubra pilaris (PRP) occurs sporadically for unknown reasons. In a few families with the inherited form, familial PRP, the condition is caused by mutations in the CARD14 gene. This gene gives instructions for making a protein that turns on other proteins that regulate genes that control the body's immune responses and inflammatory reactions.
    