Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Proximal symphalangism ?
    ### Response:
    Proximal symphalangism, which is also called Cushing's symphalangism, is a rare genetic condition characterized by the fusion of the proximal joints in the hands and feet. These individuals usually have straight fingers and are unable to make a fist. Other joints may also be affected, leading to stiff joints in the elbows, ankles and wrists.
    