U2AF1 and myelodysplastic syndrome: The major findings in this group include the detection of ASXL1 p.Gly646TrpfsTer12 (variant described in MF and connected with AML progression), RUNX1 p.Leu56Ser and ZRSR2 p.Arg169Ter (variants described in MPN and MDS and connected with fibrotic progression) and U2AF1 p.Gln157Pro (described in MDS, MPN/MDS, MF and secondary AML).