Abstract
Transient abnormal myelopoiesis（TAM）usually occurs in neonates with Down syndrome, and in approximately 20％ of those affected develop acute megakaryoblastic leukemia（AMKL）. We report a case of TAM without the physical and clinical features of Down syndrome. The percentage of peripheral blood mononuclear cells with trisomy 21 in which the GATA1 mutation was detected was 11-20％. However, cells with trisomy 21 were not detected in the buccal mucosa. The blasts and trisomy 21-positive cells possessing the GATA1 mutation disappeared without therapeutic intervention. The patient is in remission without development of AMKL. She also presents normal psychomotor development at the age of 2 years and 7 months. This article also briefly reviews previously published cases of TAM in phenotypically normal neonates. These cases were not significantly different from Down syndrome cases in terms of remission rate of TAM and AMKL incidence. Psychomotor development was normal. This is the first report confirming the disappearance of the GATA1 mutation. Considering our results, we recommend serial examination of the GATA1 mutation in patients with TAM.
