Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Uncombable hair syndrome ?
    ### Response:
    What causes uncombable hair syndrome? The stiffness of the hair in uncombable hair syndrome (UHS) is likely due to the triangular shape of the hair shaft that is seen in cross section in affected people. It has been suggested that the condition may result from premature keratinization (development of keratin) of the inner root sheath, which forms the channel for the growing hair.
    