Detection of a Cryptic KMT2A/AFDN Gene Fusion [ins(6;11)(q27;q23q23)] in a Pediatric Patient with Newly Diagnosed Acute Myeloid Leukemia

Holly E. Berg, Patricia T. Greipp, Linda B. Baughn, Corey P. Falcon, Courtney C. Jackson, Jess F. Peterson

Research output: Contribution to journalArticlepeer-review

Abstract

KMT2A gene rearrangements are a major oncogenic driver in multiple hematologic neoplasms. Apart from t(9;11)(p21;q23) (KMT2A/MLLT3) in acute myeloid leukemia (AML), KMT2A gene rearrangements are considered to convey high risk and poor overall survival. Herein, we report a case of a 7 year old boy with newly diagnosed AML and a cryptic KMT2A/AFDN gene fusion resulting from a 5'KMT2A insertional event. The results of conventional chromosome studies revealed trisomy 8 in all 20 metaphases, with normal-appearing chromosomes 6 and 11. A KMT2A break-apart FISH probe identified 2 intact copies of the KMT2A gene region and an extra 5'KMT2A signal in 85% of interphase nuclei. Subsequent FISH studies using a KMT2A/AFDN dual-color dual-fusion FISH probe revealed positive results for a single fusion in 82% of interphase nuclei, indicating a KMT2A/AFDN gene fusion. Subsequently, metaphase FISH confirmed the location of the KMT2A/AFDN fusion at 6q27. To our knowledge, this represents only the second time in the literature that a cryptic KMT2A/AFDN gene fusion resulting from a 5'KMT2A insertional event was reported.

Original languageEnglish (US)
Pages (from-to)e95-e99
JournalLaboratory medicine
Volume53
Issue number4
DOIs
StatePublished - Jul 4 2022

Keywords

  • acute myeloid leukemia (AML)
  • AFDN
  • conventional chromosome studies
  • cryptic insertion
  • fluorescence in situ hybridization (FISH)
  • KMT2A (MLL)

ASJC Scopus subject areas

  • Medicine(all)

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