Using genome-wide analysis, Ilagan et al., Kim et al., and Okeyo-Owuor et al. recently reported that the S34F/Y mutations of U2AF1 change the preferred 3′SS and enhance aberrant exon inclusion17–19, leading to hematological malignancies, including myelodysplastic syndromes (MDS). The gene discussed is U2AF1; the disease is myelodysplastic syndrome.