A new aberrantly spliced BCR‐ABL1 transcript variant (e13a1) identified in routine monitoring using different quantitative reverse transcription polymerase chain reaction techniques in a patient with chronic myeloid leukemia

Quantitative reverse transcription polymerase chain reaction (qRT‐PCR) of BCR‐ABL1 transcript level is an essential part of routine disease monitoring in patients with chronic myeloid leukemia. One patient sample (e13a2 transcript detected by nested PCR) attracted attention by revealing an aberrantly spliced BCR‐ABL1 transcript variant e13a1. The last 38 base pairs (bp) of BCR exon 13 were replaced by a 37 bp insertion of the ABL1 intron 1–2/exon 1 sequence. The rare aberrant BCR‐ABL1 fusion transcript can cause discrepancies in molecular diagnostics. This scenario highlights the importance of an individual characterization of the BCR‐ABL1 fusion sequence in case of unclear qRT‐PCR results.