Polycythemia vera (PV) - PV is a rare illness that causes the body to make too many red blood cells. The most common symptoms of PV are blood clots, heart attacks and strokes. PV has no known cause. A few studies, published more than 25 years ago, reported that PV could possibly be caused by exposure to chemicals (benzene, embalming fluid, petroleum products) or radiation.

In 2004, a change (mutation) in a gene called JAK2 was found to occur in most PV patients... Continue