Although some studies have proposed that ASXL1 truncations represent loss-of-function mutations26, 54, 56, expression of the ASXL1 frameshift mutation p.E635Rfs*15 in otherwise WT mouse bone marrow cells promoted the development of MDS-like symptoms, albeit with prolonged latency, supporting the idea that these truncations may in fact be functional27. The gene discussed is ASXL1; the disease is myelodysplastic syndrome.