Abstract
Oligonucleotide array comparative genomic hybridization, karyotype and fluorescence in situ hybridization analyses were employed to delineate the cytogenetic abnormalities in a case of pediatric acute megakaryoblastic leukemia. Here we present a unique genetic profile that includes bi-allelic deletions within 13q14, where the retinoblastoma tumor suppressor gene (RB1) resides, as well as isolated trisomy 21 without a concomitant mutation in the hematopoietic transcription factor GATA1s and translocation (17;22), that does not involve the megakaryoblastic leukemia 1 (MKL1) gene located on chromosome 22. Alteration of the RB1 gene is most likely the critical leukemogenic event in this patient.