Chromosomal translocations involving the KMT2A (MLL) gene constitute the cytogenetic hallmark of acute lymphoblastic leukemia (ALL) diagnosed in infants (< 1 year of age), giving rise to an aggressive malignancy with high relapse rates and low event-free survival (EFS) chances of 30–40% [1, 2]. The gene discussed is KMT2A; the disease is acute lymphoblastic leukemia.