 Down syndrome fetuses and neonates with one of the cited types of "GATA1" truncating mutations are in rare cases asymptomatic (i.e.silent TMD) but more commonly exhibit "in utero" or during the first months of live accumulations of immature megakaryoblasts in, and sometimes life-threatening injury to, the fetal blood-forming organ, the liver, and other tissues.While fatal in up to 20% of cases, ~80 of infants with TMD fully recover from the diseases within 4 months.