Transient abnormal myelopoiesis (TAM) and myeloid leukemia of Down syndrome (ML-DS) are associated with myeloid proliferation in trisomy 21 patients.[1] Unlike other types of congenital leukemia and myeloproliferative tumors in children, both are present in children with Down syndrome with mutations in GATA1. This evidence concerns the gene GATA1 and Down syndrome.