Type of disease: Rare conditions
Essential thrombocythemia belongs to a group of conditions called myeloproliferative disorders. Myeloproliferative disorders cause platelets, white blood cells and red blood cells to grow abnormally in the bone marrow (the soft tissue inside the hollow part of bones that helps form blood cells). In essential thrombocythemia, the body produces too many platelet cells. The signs and symptoms vary from person to person, with up to two-thirds of patients not having any symptoms when the platelet cell count first increases. Signs and symptoms may include significant increased production of megakaryocyte (a cell in the bone marrow that is responsible for making platelets), enlargement of the spleen (splenomegaly), and bleeding and/or clotting episodes. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.