Neonates with Down syndrome can present with a haematological disorder called transient abnormal myelopoiesis (TAM). While TAM is usually a self-limiting disease, patients with severe complications such as hydrops fetalis, cardiorespiratory failure and liver fibrosis have been described. Here, we present five consecutive neonates with trisomy 21 and TAM, four of whom were critically ill and were therefore treated with cytosine-arabinoside. All five patients survived.Conclusion:
severely affected neonates with Down syndrome and transient abnormal myelopoiesis might benefit from early cytostatic treatment with cytosine-arabinoside.