t(1;11)(q21;q23)

**Semantic type:** Cell or Molecular Dysfunction

**Definition:** A cytogenetic abnormality that refers to the translocation of the long arm (q21) of chromosome 1 and the long arm (q23) of chromosome 11. It is associated with KMT2A (MLL)/MLLT11 (AF1Q) fusions, acute myeloid leukemia and some cases of acute lymphoblastic leukemia.