Mutations in LUC7L2, PRPF8,SF3B1, SRSF2, U2AF1, and ZRSR2 genes occur at various frequencies ranging between 40% and 85% in different subtypes of myelodysplastic syndrome (MDS) and 5% and 10% of acute myeloid leukemia (AML) and myeloproliferative neoplasms (MPNs). The gene discussed is U2AF1; the disease is myelodysplastic syndrome.