However, TPO has no or little effect on platelet shedding from megakaryocytes.4 TPO is not only the most important growth factor for megakaryocytopoiesis, but it is also involved in maintaining the numbers of hematopoietic stem cells; this fact contributing to explain the occurrence of both thrombocytopenia and pancytopenia in CAMT patients. The gene discussed is TPO; the disease is Thrombocytopenia.