<unk>  is a grouping of several disorders caused by common defect, viz., familial or sporadic inactivating mutations in one of the two parental<unk>  genes. Being the gene haploinsufficient, mutations that cause a reduction in the cellular levels of the gene's product,<unk> , are autosomal dominant. The<unk>  protein is a transcription factor critical for the embryonic development, maintenance, and functionality of blood-forming, lymphatic-forming, and other tissue-forming stem cells. In consequence of these mutations, cellular levels of<unk>  are deficient and individuals develop over time hematological, immunological, lymphatic, or other presentations that may begin as apparently benign abnormalities but commonly progress to severe organ (e.g. lung) failure, opportunistic infections, virus infection-induced cancers, the myelodysplastic syndrome, and/or leukemia.<unk>  is a life-threatening and precancerous condition. The various presentations of<unk>  include: 1) Monocytopenia and Mycobacterium Avium Complex/Dendritic Cell, Monocyte, B and NK Lymphocyte<unk>  (i.e. MonoMAC or MonoMAC/DCML); 2) Emberger syndrome; 3) familial myelodysplastic syndrome/acute myeloid leukemia (i.e. familial MDS/AML); 3) chronic myelomonocytic leukemia (i.e. CMML); and 4) other anomalies such as aplastic anemia, chronic neutropenia, and wide-ranging immunological defects. Each of these presentations is characterized by a specific constellation of signs and symptoms but often includes signs and symptoms more characteristic of other<unk>  presentations. Furthermore, individuals with identical<unk>  gene mutations can exhibit very different presentations. Prior to 2011, MonoMAC and the Emberger syndrome were clinically defined as unrelated genetic disorders. In 2011, however, all cases of both disorders were found to be caused by inactivating mutations in the<unk>  gene. Subsequently, some but not all cases of an expanding list of other well-defined disorders have been attributed to inactivating<unk>  mutations. While MonoMAC, the Emberger syndrome, and the growing list of all other disorders marked by inactivating<unk>  gene mutations are now being classified as a single clinical entity termed<unk> , MonoMAC and the Emberger syndrome are sometimes still regarded as separate clinical entities. Here,<unk>  is taken to include all disorders caused by inactivating<unk>  mutations. Defined as such,<unk>  is an unexpectedly common underlying cause for a growing list of disorders. Importantly, however, its treatment differs critically from that used to treat cases of these disorders which are not due to<unk> .
GATA2 deficiency
WNT4 deficiency
Janus kinase 3 deficiency
ZC4H2 deficiency
CDK13-related disorder
LRBA deficiency
ZAP70 deficiency
1p36 deletion syndrome