Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the symptoms of Polycythemia vera ?
    ### Response:
    What are the signs and symptoms of Polycythemia vera? The Human Phenotype Ontology provides the following list of signs and symptoms for Polycythemia vera. If the information is available, the table below includes how often the symptom is seen in people with this condition.
    