GATA2 deficiency syndrome, caused by germline mutations in the hematopoietic transcription factor GATA2, stands out because multiple lineages can be affected and patients often present with monocytopenia, B cell deficiency, NK (natural killer) cell deficiency and Dendritic Cell deficiency (Dickinson et al., 2011; Novakova et al., 2016). The gene discussed is GATA2; the disease is B cell deficiency.