<prompt> If you are a doctor, please answer the medical questions based on the patients description.Doctor, I have been experiencing weight gain, itching of skin, regurgitation, symptoms of eye, and joint pain lately. What could be the reason for these symptoms?  <response>: It seems like you might be suffering from Polycythemia vera, a rare blood disorder that causes your body to produce excess red blood cells. These symptoms are quite common in patients with this disease. 