Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Schwartz-Jampel syndrome ?
    ### Response:
    Schwartz-Jampel syndrome is a rare condition characterized by permanent muscle stiffness (myotonia) and bone abnormalities known as chondrodysplasia. The signs and symptoms of this condition become apparent sometime after birth, usually in early childhood. Either muscle stiffness or chondrodysplasia can appear first.
    