Atlas of Genetics and Cytogenetics in Oncology and Haematology
t(12;21)(p13;q22)
| Identity |
 | |
| t(12;21)(p13;q22) R- bandind and FISH - Courtesy Hossein Mossafa. | |
| Clinics and Pathology |
| Disease | B cell ALL |
| Phenotype / cell stem origin | L1 and L2, CD10+ |
| Epidemiology | 15 to 35% of paediatric B-lineage ALL: so far the most frequent translocation in this group; rare or absent in adults and in infants; age: children; no case >20 yrs so far; male and female equally represented |
| Clinics | standard ALL |
| Prognosis | CR in all cases; prognosis seems good |
| Cytogenetics |
| Cytogenetics Morphological | t(12;21) often remained undetected |
| Cytogenetics Molecular | easily detected by chromosomes 12 and 21 painting or specific probes |
| Additional anomalies | frequent del(12)(p12) on the other chromosome; in rare cases duplication of der(21)t(12;21); looks like a +21 |
| Variants | t(6;12;21), t(3;12;21) |
| Genes involved and Proteins |
| Gene Name | ETV6 |
| Location | 12p12 |
| Protein | contains a HLH domain and a ETS-DNA binding domain; ETS-related transcription factor |
| Gene Name | AML1 |
| Location | 21q22 |
| Dna / Rna | transcription is from telomere to centromere |
| Protein | contains a Runt domain and, in the C-term, a transactivation domain; forms heterodimers; widely expressed; nuclear localisation; transcription factor (activator) for various hematopoietic-specific genes |
| Result of the chromosomal anomaly |
 | |
| ETV6 (TEL) and RUNX1 (AML1) breakpoints in the t(12;21) / 5' ETV6 - 3' RUNX1 fusion gene - Courtesy Hossein Mossafa. | |
| Description | TEL-AML1 chimaeric gene; 5' centromere to 3' telomere orientation |
| Transcript | the fusion transcript on chromosome 21 TEL -AML1 is the crucial one; the AML1-TEL transcript is absent in some cases; the other TEL allele is often deleted. |
| Detection | RT-PCR of the fusion transcript |
| Description | Helix loop helix of TEL fused to the nearly entire AML1 protein, comprising the Runt domain and the transactivation domain |
| External links |
| Other database | t(12;21)(p13;q22) | Mitelman database (CGAP - NCBI) |
| Bibliography |
| High frequency of t(12;21) in childhood B-lineage acute lymphoblastic leukemia. |
| Romana SP, Poirel H, Leconiat M, Flexor MA, Mauchauffˆ© M, Jonveaux P, Macintyre EA, Berger R, Bernard OA |
| Blood. 1995 ; 86 (11) : 4263-4269. |
| PMID 7492786 |
| The 12;21 translocation involving TEL and deletion of the other TEL allele: two frequently associated alterations found in childhood acute lymphoblastic leukemia. |
| Raynaud S, Cave H, Baens M, Bastard C, Cacheux V, Grosgeorge J, Guidal-Giroux C, Guo C, Vilmer E, Marynen P, Grandchamp B |
| Blood. 1996 ; 87 (7) : 2891-2899. |
| PMID 8639909 |
| Fusion of PDGF receptor beta to a novel ets-like gene, tel, in chronic myelomonocytic leukemia with t(5;12) chromosomal translocation. |
| Golub TR, Barker GF, Lovett M, Gilliland DG |
| Cell. 1994 ; 77 (2) : 307-316. |
| PMID 8168137 |
| Contributor(s) |
| Written | 08-1997 | Jean-Loup Huret and Alain Bernheim |
| Laboratoire de Cytogénétique, UMR 1599 CNRS, Institut Gustave Roussy, 94805 Villejuif, France |
| Citation |
| This paper should be referenced as such : |
| Huret JL and Bernheim A . t(12;21)(p13;q22). Atlas Genet Cytogenet Oncol Haematol. August 1997 . URL : http://AtlasGeneticsOncology.org/Anomalies/t1221.html |
This paper is referenced by INIST as such : |
| http://documents.irevues.inist.fr/bitstream/handle/2042/32031/08-1997-t1221.pdf [ Bibliographic record ] |
| © Atlas of Genetics and Cytogenetics in Oncology and Haematology | indexed on : Sat Mar 9 12:37:58 CET 2013 |
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