In the context of myeloid leukemia, mutations in ASXL1 have been shown to lead to the loss of ASXL1 expression and a consequent reduction of PRC2-mediated histone 3 lysine 27 tri-methylation (H3K27me3), a histone modification associated with gene repression [25]. The gene discussed is ASXL1; the disease is myeloid leukemia.