t(X;17) as the sole karyotypic anomaly in a case of M(3r) subtype of acute promyelocytic leukemia without RARalpha rearrangement.

We describe here a unique chromosomal abnormality found in a patient with M(3r) subtype of APL. Neither t(15;17) nor rearrangement of RARalpha was detected by routine R-banded chromosome as well as fluorescence in situ hybridization (FISH) analysis using PML/RARalpha dual-color dual-fusion translocation probe and RARalpha dual-color break apart rearrangement probe. Instead of the typical rearrangement between chromosomes 15 and 17, all cells analyzed had a translocation between X and 17 as the sole karyotypic anomaly. The translocation was conformed by whole chromosome painting (WCP) with painting probes of chromosomes X and 17. To our knowledge, this is the first documented APL with a novel translocation involving chromosomes X and 17 without RARalpha gene rearrangement. Copyright 2009. Published by Elsevier Ltd.