U2AF1 and myelodysplastic syndrome: In addition, the majority of MDS patients also harbored at least one mutation in a spliceosomal gene, such as SF3B1 (n = 16), SRSF2, or U2AF1 (n = 6) or carry only DNMT3A/TET2 mutations (n = 10) (Table 1, Supplementary Data 1, Supplementary Fig. 1A).