Somatic mutations in genes encoding four splicing factors (U2AF1, SF3B1, SRSF2 and ZRSR2) have recently been reported in up to 50% of myelodysplastic syndromes (MDS) and related neoplasms and at lower frequencies in a variety of solid tumors [1–9]. Here, U2AF1 is linked to myelodysplastic syndrome.