Asymptomatic carriers of GATA2 mutation may develop cellular deficiency, elevated Flt3L, loss of BM progenitors, and clonal myelopoeisis. (A) Three pedigrees identified (mutation indicated) containing asymptomatic relatives (clinical core = 0), carrying GATA2 mutation (open symbols, arrowed). Gray symbols identify 2 patients with either elevated Flt3L (>200 pg/ml) or cytopenia. Filled symbols indicate affected patients with mutation (clinical score = 1 to 4). (B) DC, monocyte, and lymphocyte profiles of patient #5, 1 of 3 healthy carriers of GATA2 mutation showing a normal cellular phenotype at the first point of analysis in 2010. Populations: (1) CD14⁺ monocyte; (2) CD16⁺ monocyte; (3) pDC; (4) CD34⁺ progenitors; (5) CD141⁺ mDC; (6) CD1c⁺ mDC; (7) B cell; (8) T cell; and (9) NK cell. (C) Summary of DC and monocyte counts relative to reference ranges for the asymptomatic carriers. Case #5 (filled circle) is shown at first analysis in 2010. Case #21 (filled square) already has cytopenia. (D) Detailed analysis of case #5 showing the loss of cells and rising Flt3L over a 3-year period. (E) BM analysis of case #5 showing loss of B, NK, MLP, and GMP progenitors at midpoint when no cytopenia was evident. CMP, common myeloid progenitor; MEP, megakaryocyte-erythroid progenitor; MPP, multi-potent progenitor. (F) Pattern of X inactivation in females with GATA2 mutation at different stages of clinical evolution. Dominance of >75% is considered evidence of clonal hematopoiesis.