Chromosome 11 rearrangements and specific MLL amplification revealed by spectral karyotyping in a patient with refractory anaemia with excess of blasts (RAEB)

A patient with refractory anaemia with excess of blasts (RAEB) had a complex karyotype with multiple markers. Spectral karyotyping (SKY) showed rearrangements including three different der(11), containing a very high number of MLL gene copies, shown by fluorescence in situ hybridization (FISH) analysis. Fibre‐FISH experiments disclosed the presence of chromatin fibres with multiple MLL copies with a head‐to‐tail pattern. Apparently, no other region flanking the MLL site was present in the three der(11). MLL amplification was confirmed by the reverse transcription polymerase chain reaction (RT‐PCR). The patient died 6 months after diagnosis, supporting the severe prognosis of sole MLL amplification.