A Rare Case of Pericentric Inversion, Inv(9)(p13q34) of the Der(9)t(9;22)(q34;q11) in A Patient with Chronic Myeloid Leukemia – A Case Report

As we know, the Philadelphia chromosome (Ph) is a highly specific marker for chronic myeloid leukemia (CML). This hematological disease is characterised by the formation of the BCR/ABL1 fusion gene, usually with typical translocation pattern including 9q34 and 22q11. In this paper we describe a 55 years old female patient with typical clinical and haematological signs of CML and a chromosome 9 differing from that which normally participates in translocation t(9;22). The karyotype of this Ph positive patient is characterised by pericentric inv(9)(p13q34) of the der(9)t(9;22)(q34;q11). Reverse transcriptase-polymerase chain reaction revealed a e14a2 type of BCR/ABL1 fusion transcript. As a consequence of this unusual translocation, FISH also found the separation of the ABL1/BCR1 fusion gene on chromosome 9. On reviewing the literature, to date only 10 Ph-positive leukemia patients have been noticed to have pericentric inversion inv(9)(p22q34)der(9)t(9;22)(q34;q11). No one case has been described with pericentric inversion inv(9)(p13q34) of the der(9)t(9;22)(q34;q11). This indicate that pericentric inv(9)(p13q34) of the der(9)t(9;22)(q34;q11) is a novel, rare, chromosomal abnormality in Ph-positive CML.