In a transplant setting, treatment of mice bearing Dnmt3a–/– cells with a PI3Kα/β or PI3Kα/δ inhibitor rescues Dnmt3a mutant–associated hematologic abnormalities, including hepatosplenomegaly, myeloid cell infiltration in the tissues, and anemia as well as thrombocytopenia. The gene discussed is DNMT3A; the disease is anemia.