Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Metachondromatosis ?
    ### Response:
    Metachondromatosis (MC) is a rare bone disorder characterized by the presence of both multiple enchondromas and osteochondroma-like lesions. The first signs occur during the first decade of life. Osteochondromas most commonly occur in the hands and feet (predominantly in digits and toes), and enchondromas involve the iliac crests and metaphyses of long bones.
    