INDEPENDENCE DAY. On July 4, 1776, the thirteen colonies claimed their independence from England, an event which eventually led to the formation of the United States.
Polycythemia vera is a rare, chronic disorder involving the overproduction of blood cells in the bone marrow (myeloproliferation). The overproduction of red blood cells is most dramatic, but the production of white blood cells and platelets are also elevated in most cases.
But in polycythemia vera, your bone marrow makes too many of some blood cells. The mutation that causes polycythemia vera is thought to affect a protein switch that tells the cells to grow. Specifically, it's a mutation in the protein Janus kinase 2 (JAK2). Most people with polycythemia vera have this mutation.