GATA2 and myelodysplastic syndrome: In humans, haploinsufficiency resulting from inactivating mutations in its +9.9 kb enhancer is one of the causes of the disorder known as GATA2 deficiency.256,257 Patients with these defects exhibit various cytopenias and frequent infections and are at risk for developing familial myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML).258