Chromosomal translocations of 11q23 of the mixed lineage leukemia gene (known as KMT2A, MLL, or HRX) account for 5–10% of all acute leukemia cases, including acute lymphoid, myeloid, and biphenotypic leukemia, and are generally associated with inferior prognosis [1]. The gene discussed is KMT2A; the disease is leukemia.