Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Osteomesopyknosis ?
    ### Response:
    Osteomesopyknosis is a bone disorder characterized by abnormal hardening of bone (osteosclerosis). It is generally limited to the axial spine, pelvis, and proximal part of the long bones, which is what distinguishes this condition from other sclerosing bone disorders.
    