Novel type of BCR-ABL transcript in a chronic myelogenous leukaemia patient relapsed after bone marrow transplantation

We identified a novel BCR-ABL transcript in a chronic myelogenous leukaemia (CML) patient who relapsed after bone marrow transplantation (BMT), containing a fusion between part of BCR exon 3, 44 nucleotides derived from ABL intron 1b and ABL exon 2. The breakpoints were located within BCR exon 3 on chromosome 22 and within the ABL intron 1b on chromosome 9, and the transcript derives from a splicing of ABL exon 2 to a putative splicing acceptor site 44 nucleotides downstream to the breakpoint on chromosome 9. The patient's clinical course strengthens the idea that short forms of BCR-ABL transcripts are associated with a more aggressive disease.