Recently, heterozygous GATA-2 germline mutations, both inherited and de novo, were reported to cause three overlapping clinical entities, characterized by a predisposition to myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML): (1) familial MDS/AML, (2) Emberger syndrome and (3) an immunodeficiency termed monocytopenia characterized by mycobacterium avium complex (MonoMAC)/dendritic cell, monocyte, B- and NK-lymphoid deficiency (DCML) [2–4]. The gene discussed is GATA2; the disease is acute myeloid leukemia.