A type of absolute erythrocytosis (increased red cell mass) caused by an intrinsic defect in the stem cell population leading to
autonomous proliferation of red cell progenitors within the bone marrow. There are two types of primary erythrocytosis:
- Congenital erythrocytosis (primary familial or congenital polycythemia) caused by gain of function mutations in the erythropoietin receptor.
- Acquired erythrocytosis (polycythemia vera) caused by a somatic mutation in the Jak2 gene.