We report the case of a 26-year-old male patient with chronic myelogenous leukemia in the chronic phase with the e13a3 (b2a3) variant of BCR-ABL1 fusion...The variant fusion transcript level was successfully monitored by the TaqMan assay using a forward primer and probe both in exon 13 of BCR and a reverse primer in exon 3 of ABL1. The patient responded extremely well to imatinib treatment...