Brief communicationA new variant of KMT2A(MLL)-FLNA fusion transcript in acute myeloid leukemia with ins(X;11)(q28;q23q23)
Section snippets
Case report
The patient is a 7-month-old male child who was referred to the Central Clinical Hospital (Tula, Russian Federation) in September 2011 because of pain in his left knee and coxa. Physical examination revealed hepatosplenomegaly and prominent lymphadenopathy. The leukocyte count was 80.7 × 109 cells/L. Morphological, cytochemical, and immunological studies revealed acute myelomonocytic leukemia. The infant was treated according to the Moscow-Minsk-AML-2006 protocol. He received induction therapy
Results
G-banding of the patient sample showed a karyotype 47,XY,+6[14]. The mFISH analysis also didn't reveal any structural aberrations. FISH analysis showed nonstandard disruption of the KMT2A gene on 70 of 100 interphase nuclei. The distribution of signals corresponded to two KMT2A copies and one copy of 5′-KMT2A. FISH analysis on metaphases showed that the additional 5′-KMT2A material localized in the long arm of the X chromosome (Figure 1).
LDI-PCR analysis identified the KMT2A-FLNA fusion gene
Discussion
Until now, only one case of a KMT2A-FLNA fusion gene had been described (8). This was an infant AML case (5-month-old boy with AML M4) that corresponds to our data. Similarly, the fusion gene appeared as a consequence of the insertion of a large portion of chromosome 11 material into the X chromosome. The same mechanism was observed in our case, although the insertion was cryptic. A possible explanation for this phenomenon is that the transcriptional orientation of KMT2A and FLNA is different,
Acknowledgment
The authors thank Aleksey Barinov (Moscow City Cancer Hospital No. 62, Moscow, Russia) for technical assistance.
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