Based on extensive information indicating that in mice the ratio between the GATA1 and GATA2 content (Gata2/Gata1 switch) controls the proliferation of murine stem/progenitor cells (Bresnick et al., 2010), it is not surprising that acquired frame shift and point mutations impairing GATA1 functions induce leukemia in humans. The gene discussed is GATA1; the disease is leukemia.