<P> Essential thrombocytosis (ET), also known as essential thrombocythemia, is a disorder characterized by elevated numbers of circulating platelets . The disease occurs in 1--2 per 100,000 people . The 2016 WHO requirements for diagnosis include> 450,000 platelets / μL of blood (normal 150,000--400,000) and a bone marrow biopsy . Some of the consequences of having such high numbers of platelets include thrombosis or clots throughout the body . Thrombi form more frequently in arteries than veins . It seems ironic that having platelet counts above 1,000,000 platelets / μL can lead to hemorrhagic events . Recent evidence suggests that the majority of ET cases are due to a mutation in the JAK2 protein, a member of the JAK - STAT pathway . Evidence suggests that this mutation renders the megakaryocyte hypersensitive to thrombopoietin and causes clonal proliferation of megakaryocytes . There is a significant risk of transformation to leukemia with this disorder . The primary treatment consists of anagrelide or hydroxyurea to lower platelet levels . </P> <P> Congenital amegakaryocytic thrombocytopenia (CAMT) is a rare inherited disorder . The primary manifestations are thrombocytopenia and megakaryocytopenia, i.e. low numbers of platelets and megakaryocytes . There is an absence of megakaryocytes in the bone marrow with no associated physical abnormalities . The cause for this disorder appears to be a mutation in the gene for the TPO receptor, c - mpl, despite high levels of serum TPO . In addition, there may be abnormalities with the central nervous system including the cerebrum and cerebellum that could cause symptoms . The primary treatment for CAMT is bone marrow transplantation . </P> <P> Bone marrow / stem cell transplant is the only remedy for this genetic disease . Frequent platelet transfusions are required to keep the patient from bleeding to death until transplant has been completed, although this is not always the case . </P> <P> There appears to be no generic resource for CAMT patients on the web and this is potentially due to the rarity of the disease . </P>

A megakaryocyte is the precursor to a macrophage