Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Andersen-Tawil syndrome ?
    ### Response:
    Andersen-Tawil syndrome is a type of long QT syndrome and is also considered a rare form of periodic paralysis. It causes episodes of muscle weakness, changes in heart rhythm (arrhythmia), and developmental abnormalities. Physical abnormalities associated with this condition typically affect the head, face, and limbs.
    