In the current study, 5 (17.2%) had mutations specific for AML developed from MDS, in genes such as SRSF2, SF3B1, U2AF1, ZRSR2, ASXL1, EZH2, BCOR, or STAG2. When limited to AML with a history of MDS, one patient had an SRSF2 mutation, one had a U2AF1 mutation, and one had a STAG2 mutation. The gene discussed is U2AF1; the disease is myelodysplastic syndrome.