U2AF1 and myelodysplastic syndrome: Two recent large studies showed in MDS bone marrow CD34+ cells that the common SF mutations resulted in different alterations in splicing and largely affected different genes.8▪,9▪ Alternative exon usage was predominant in SRSF2- and U2AF1-mutant MDS cases, while SF3B1 mutations were mainly associated with intron retention events and the use of cryptic 3’ splice sites.8▪,9▪