Among haematological malignancies, U2AF1 and U2AF2 mutations are largely restricted to myeloid neoplasms, especially high-risk myelodysplastic syndromes and acute myeloid leukaemia in which U2AF1 mutants may alter the differential splicing of many genes that affect various biological pathways, including DNA damage response (ATR and FANCA) and epigenetic regulation (H2AFY, ASXL1, BCOR, and DNMT3B). Here, U2AF1 is linked to myelodysplastic syndrome.