A Case of Novel GATA-1 Mutation-positive Transient Abnormal Myelopoiesis With Life-threatening Complications in a Neonate With Down Syndrome.

Transient abnormal myelopoiesis is a transient myeloproliferative disorder seen in ∼15% to 20% of infants with Down syndrome. These infants are usually asymptomatic, requiring only monitoring, but they can have variable severity of symptoms up to multisystemic dysfunction requiring chemotherapy. GATA-1 somatic mutations acquired in utero are pathognomic of this entity and present nearly in all cases. Herein, we present a case of Down syndrome in a neonate who presented within her first week of life with life-threatening features of transient abnormal myelopoiesis requiring chemotherapy support. In addition, next-generation sequencing revealed a small mutant clone (8%) positive for a novel frameshift GATA-1 mutation.