Complete loss of Asxl1 in mice impairs hematopoiesis and causes developmental abnormalities including dwarfism, anophthalmia, and near-penetrant embryonic lethality, whereas the surviving Asxl1−/− mice or hematopoietic-specific deletion of Asxl1 had shortened lifespan and developed MDS features, but not full-blown myelodysplasia or leukemia (Fisher et al., 2010). The gene discussed is ASXL1; the disease is Myelodysplasia.