I was diagnosed with polycythemia vera 20 years ago, and I am JAK2 positive. My brother recently learned that his red blood cell count is very high and will now be seeing a hematologist. Is it strange that my brother may have the same condition, even though it is so rare? I researched a polycythemia vera cluster that occurred in several counties and learned that my brother and I had lived in one of them. Has anyone else researched this issue?