The prevalence of mutations in ASXL1 (4% versus 24%; P < 0.001), RUNX1 (2% versus 24%; P < 0.001), SRSF2 (2% versus 13%, P = 0.02), BCOR (0 versus 9%; P = 0.02) and STAG2 (0 versus 8%; P = 0.03) were significantly less in subjects with MDS-biTP53 compared with those with MDS-IB. The gene discussed is ASXL1; the disease is myelodysplastic syndrome.