Below is an instruction from Human. Write a response.
    ### Instruction:
    Is PPM-X syndrome inherited ?
    ### Response:
    More than 99 percent of PPM-X syndrome cases occur in people with no history of the disorder in their family. Many of these cases result from new mutations in the MECP2 gene.  A few families with more than one affected family member have been described. These cases helped researchers determine that PPM-X syndrome has an X-linked pattern of inheritance.
    