transient myeloproliferative syndrome

Transient myeloproliferative disease

Transient myeloproliferative disease (TMD) occurs in a significant percentage of individuals born with the congenital genetic disorder, Down syndrome. It may occur in individuals who are not diagnosed with the syndrome but have some hematological cells containing genetic abnormalities that are similar to those found in Down syndrome. TMD usually develops in utero, is diagnosed prenatally or within ~3 months of birth, and thereafter resolves rapidly and spontaneously. However, during the prenatal-to-postnatal period, the disease may cause irreparable damage to various organs and in ~20% of individuals death. Moreover, ~10% of individuals diagnosed with TMD develop acute megakaryoblastic leukemia at some time during the 5 years following its resolution. TMD is a life-threatening, precancerous condition in fetuses as well as infants in their first few months of life. Transient myeloproliferative disease involves the excessive proliferation of non-malignant megakaryoblasts. Megakaryoblasts are hematological precursor cells which mature to megakaryocytes. Megakaryocytes release platelets into the bloodstream. Platelets are critical for normal blood clotting. In consequence of this mutation, megakaryoblasts fail to mature properly, accumulate in multiple organs, may damage these organs, and may become cancerous. The diseases also causes a reduction in the maturation of erythroblasts to circulating red blood cells and, consequently, mild anemia. Most individuals with TMD have clinical evidence of damage to various organs, particularly the liver, due to megakaryoblast infiltrati...