Mutations in the ASXL genes are frequently associated with alterations in RUNX1. Interestingly, ASXL1 and ASXL2 mutations are mutually exclusive in t(8;21)/RUNX1-RUNX1T1 AML, raising the possibility that they have convergent downstream and/or synthetic lethal effects when they co-occur [59]. The gene discussed is RUNX1T1; the disease is acute myeloid leukemia.