Chronic myeloid leukemia (CML) is characterized in 90% of patients by the presence of the reciprocal translocation t(9;22)(q34;q11) leading to the fusion of the BCR and ABL genes. Most patients with Philadelphia chromosome positive CML express either the e13a2 (b2a2) or e14a2 (b3a2) MBCR-ABL mRNA. Some variant cases have been reported expressing the fusion e1a2 ( mBCR-ABL ) or e19a2 (μBCR-ABL ). Very rare atypical transcripts such as e13a3, e14a3 or e6a2 have been described. We report here a sixth case of a Ph positive patient with an e6a2 BCR-ABL fusion transcript and describe for the first time a chimeric molecule alternatively spliced for exon 5 of the BCR gene. [ABSTRACT FROM AUTHOR]