These mutations occur in genes with known roles in regulating chromatin and/or methylation states in hematopoietic progenitors (e.g., mixed-lineage leukemia (MLL)), or exert a role in altering epigenetic pattern in myeloid malignancies (e.g., TET methylcytosine dioxygenase 2 (TET2), DNA methyltransferase 3A (DNMT3A), sex combs-like 1 (ASXL1), isocitrate dehydrogenase (IDH) 1 and IDH2). The gene discussed is KMT2A; the disease is leukemia.