In recent years, genome and exome-wide sequencing studies in MDS have uncovered a number of recurrent somatic mutations within mRNA splicing factors, including SF3B1, SRSF2, U2AF1 and ZRSR2. The most frequent of these were in SF3B1, representing 17% of all mutations in MDS2, which in isolation generally infer a better prognosis. The gene discussed is U2AF1; the disease is myelodysplastic syndrome.