X chromosome insertion in the MLL gene in a case of childhood acute myeloblastic leukemia.
Band 11q23 is known to be involved in translocations and insertions with a variety of partner chromosomes. These lead to MLL rearrangement, resulting in a fusion with numerous genes. We report here the case of a 5-month-old boy presenting with hemianopsia and severe diffuse intravascular coagulopathy in whom a diagnosis of acute myeloblastic leukemia (AML) French-American-British M4 classification was made. Conventional cytogenetic techniques showed an ins(11;X) (q23;q28q12). Fluorescent in situ hybridization (FISH) with whole chromosome paints confirmed this finding. Using a specific probe, the MLL gene was found to be disrupted, a portion of the X chromosome being inserted between the 5' and 3' regions of the MLL gene. Although some cases of insertion involving chromosomes X and 11 have been reported in AML, this appears to be the first case involving band Xq28. We postulate that this chromosomal rearrangement led to the fusion of the 5' region of the MLL gene with a yet unidentified gene located in band Xq28.
Arnaud
Bertrand
B
Service de Cytogénétique, Cytologie et Biologie de la Reproduction, CHU Morvan, Brest, France.
Morel
Frédéric
F
Douet-Guilbert
Nathalie
N
Le Bris
Marie-Josée
MJ
De Braekeleer
Marc
M
D002869:Chromosome Aberrations; D002880:Chromosomes, Human, Pair 11 / Q000235:genetics*; D041321:Chromosomes, Human, X / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D015321:Gene Rearrangement; D011495:Histone-Lysine N-Methyltransferase; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D007621:Karyotyping; D015479:Leukemia, Myelomonocytic, Acute / Q000235:genetics*; D008297:Male; D051788:Myeloid-Lymphoid Leukemia Protein; D011519:Proto-Oncogenes; D014157:Transcription Factors; D016335:Zinc Fingers
D004268:DNA-Binding Proteins; C497422:KMT2A protein, human; D014157:Transcription Factors; D051788:Myeloid-Lymphoid Leukemia Protein; D011495:Histone-Lysine N-Methyltransferase