Hyperdiploid karyotype in a childhood MDS patient.

We present a rare case of a paediatric myelodysplastic syndrome (MDS) with congenital anomalies (frontal bossing and premature closure of anterior fontanelle). The case showed the clinical and biological features of a refractory anaemia excess blasts (RAEB). Bone marrow (BM) cytogenetics demonstrated a hyperdiploid karyotype, with several numerical abnormalities and unidentified rearrangements. Fluorescence in situ hybridization (FISH) using chromosome specific alpha-satellite and whole chromosome-specific painting probes verified the hyperdiploid karyotype, and confirmed the origin of the unknown markers and rearrangements more reliably than would be possible using conventional cytogenetic techniques.