Y-chromosome loss as the sole karyotypic anomaly with 3′RARα submicroscopic deletion in a case of M3r subtype of acute promyelocytic leukemia

Abstract

Acute promyelocytic leukemia (APL) is characterized by the presence of a chromosomal rearrangement involving retinoic acid receptor alpha (RARα) gene generating the X-RARα fusion. We describe here a unique RARα gene rearrangement in a patient with M3r subtype of APL. Conventional cytogenetic analysis revealed Y-chromosome loss as the sole karyotypic anomaly. No X-RARα fusion was detected by fluorescence in situ hybridization (FISH) using PML/RARα dual-color dual-fusion translocation probe set, or RARα dual-color break apart rearrangement probe or reverse-transcription polymerase chain reaction (RT-PCR). However, FISH using RARα dual-color break apart rearrangement probe showed a deletion of the entire 3′-end of one allele of RARα gene. To our knowledge, this is the first documented APL with 3′RARα submicroscopic deletion which is not associated with X-RARα fusion. The molecular consequences of this anomaly remain to be elucidated.