Thrombocytopenia is normally accompanied by raised TPO levels (when the megakaryocyte-platelet mass is reduced), and it has been previously reported that besides a direct effect of TPO on megakaryocyte proliferation and maturation, TPO also influences directly hematopoietic stem cell (HSC) quiescence and cycling [40, 47]. The gene discussed is TPO; the disease is Thrombocytopenia.