Complex karyotype defined by molecular cytogenetic FISH and M-FISH in an infant with acute megakaryoblastic leukemia and neurofibromatosis

Acute myeloid leukemia in childhood is a heterogeneous group of diseases, and different epidemiologic factors are involved in the etiopathogenesis. Genetic syndromes are one of the predisposing factors of acute myeloid leukemia (AML), including Down syndrome, Bloom syndrome, and neurofibromatosis. Acute megakaryoblastic leukemia (AMKL) is the main subtype in Down syndrome infants, and acquired chromosomal anomalies are closely related to the physiopathology of the illness. The main chromosomal anomalies in AMKL are structural, such as t(1;22); however, complex karyotypes are also common. Here we describe the case of an infant with neurofibromatosis developing AMKL with a complex karyotype including 5q and 17q deletions, TP53 deletion, and an unusual unbalanced chromosomal translocation t(11;19)(q13;p13), leading to three copies of the MLL gene.