Monosomy 7 and unbalanced t(1;7) in an adolescent boy with myelodysplastic syndrome

Monosomy 7 occurs in approximately 5% of cases of myelodysplastic syndrome (MDS) in children and is associated with a poor prognosis. The unbalanced translocation t(1;7) is common in therapy-related MDS in adults but is extremely rare in children, with only three cases reported to date. We describe a pediatric case of MDS with the unusual combination of monosomy 7 and unbalanced t(1;7) in two distinct clones. Both clones were detected at diagnosis and have persisted throughout the course of MDS in this patient, a 16-year-old boy without prior exposure to known mutagens. Because of recurrent severe infections associated with neutropenia, he was treated with recombinant human granulocyte-macrophage colony-stimulating factor. This therapy improved the neutrophil count but did not alter the karyotype or the progression of disease.