To achieve this goal, we performed a comprehensive analysis of bone marrow biopsies from 57 children diagnosed with refractory cytopenia of childhood (RCC) or MDS with excess blasts (MDS-EB), with or without GATA2 germline mutations, focusing on hematopoiesis and the hematopoietic niche, including the composition of its microenvironment. Here, GATA2 is linked to myelodysplastic syndrome.