Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Loeys-Dietz syndrome ?
    ### Response:
    Loeys-Dietz syndrome is a disorder that affects the connective tissue in many parts of the body. Connective tissue provides strength and flexibility to structures such as bones, ligaments, muscles, and blood vessels.  There are four types of Loeys-Dietz syndrome, labelled types I through IV, which are distinguished by their genetic cause.
    