Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the symptoms of Danon disease ?
    ### Response:
    What are the signs and symptoms of Danon disease? Danon disease is characterized by cardiomyopathy. Cardiomyopathy causes the heart muscle to enlarge or become thicker and more rigid than normal. This may make the heart less able to pump blood through the body and can cause serious complications, including sudden death.
    