Chromosomal abnormalities in childhood acute nonlymphocytic leukemia (M4).

A new reciprocal, apparently balanced translocation between chromosomes 7 and 22, i.e., t(7;22)(p22;q13), in association with inv(16)(p13q22) in a child with acute nonlymphocytic leukemia (M4) is reported. Five percent of her bone marrow cells contained both of these aberrations while 90% of her cells have the pericentric inversion of chromosome 16 as the sole abnormality. A clonal evolution of the unusual cell line may be associated with atypical clinical presentation. The presence of inversion 16 in adults has a better prognosis as compared with children. A concise review on the cytogenetic findings in children with ANLL(M4) is also provided.