The prevalence of KMT2A gene rearrangements is bimodal with translocations found in up to 80% of infants (diagnosed at less than 1 year of age) with acute lymphoblastic leukemia (ALL) and in young to middle-aged adults with acute myeloid leukemia (AML) (1, 2). This evidence concerns the gene KMT2A and acute myeloid leukemia.