In our MDS cohort, 19 different genes were mutated: ASXL1 (9/20, 45%); U2AF1 (6/20, 30%); TET2 (4/20, 20%); RUNX1 (3/20, 15%); PHF6 (3/20, 15%); SF3B1 (2/20, 10%), CBL (2/20, 10%), TP53 (2/20, 10%), EZH2 (2/20, 10%), PPM1D (2/20, 10%) and CCND1, DNMT3A, IDH1, KMT2A, SETBP1, STAG2, BCOR, ZRSR2 and SRSF2 (1/20, 5% each) (Fig. 1b). The gene discussed is PPM1D; the disease is myelodysplastic syndrome.