t(1;21)(p36;q22) RUNX1/PRDM16

2006-03-01   Marian Stevens-Kroef 

1.Clinical Cytogeneticist, UMC St. Radboud, Dept. Human Genetics, Div. Cytogenetics, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
2.Genetics, Dept Medical Information, University of Poitiers, CHU Poitiers Hospital, F-86021 Poitiers, France

Clinics and Pathology

Disease

Acute myeloid leukemia (AML or AML: acute myeloid leukemia) and myelodysplastic syndromes (MDS); 2 of 5 cases at least are secondary to toxic exposure

Note

Only 5 cases described so far one with features identical to a case of , and a case of t(19;21)(q13.4;q22)

Etiology

Two of the reported cases are therapy-related, in another case, AML occurred about 50 years after radiation exposure from nuclear explosions.
Atlas Image

Prognosis

poor; median survival 6 months

Cytogenetics

Atlas Image
FISH analysis using RUNX1 (red) probe. Three signals for RUNX1 are observed; on the normal chromosome 21, and on the derivative chromosomes 1 and 21.

Additional anomalies

Genes Involved and Proteins

Note
The gene involved in 1p36 is unknown
Gene name
PRDM16 (PR domain containing 16)
Location
1p36.32
Note
This gene is also involved in the t(1;3)(p36;q21) (AML/MDS)
Protein description
Zinc-finger protein, containing two DNA binding domains and a PRDI-BF1 (positive regulatory domain I binding factor 1/ RIZ (retinoblastoma-interacting zinc finger protein) homologous (PR) domain at the N-terminus.
Gene name
RUNX1 (runt-related transcription factor 1 (acute myeloid leukemia 1; aml1 oncogene))
Location
21q22.12
Dna rna description
transcription is from telomere to centromere
Protein description
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

Note

Two different chimeric transcripts have been identified. One contains the exon 1 to 6 of RUNX1 including the runt domain, fused to sequences derived from intron 1 of PRDM16. The other fusion transcript contains exons 1 to 6 of RUNX1 and almost the entire PRDM16 coding region (see figure below).
Atlas Image
Schematic representation of RUNX1 and PRDM16 (fusion) genes.
Upper panel: normal genomic structures of PRDM16 and RUNX1 (non-coding parts in bleu). A cryptic exon, residing within intron 1 of PRDM16, is indicated in green (speckled).
Lower panel: structure of RUNX1-PRDM16 fusion transcripts. Exons are numbered on the basis of consensus gene sequences. Exon sizes are not to scale.

Description

5RUNX1- 3PRDM16

Bibliography

Pubmed IDLast YearTitleAuthors
108459432000A novel syndrome of radiation-associated acute myeloid leukemia involving AML1 gene translocations.Hromas R et al
97635731998CBFA2(AML1) translocations with novel partner chromosomes in myeloid leukemias: association with prior therapy.Roulston D et al
160156452005Novel RUNX1-PRDM16 fusion transcripts in a patient with acute myeloid leukemia showing t(1;21)(p36;q22).Sakai I et al
165983042006Identification of truncated RUNX1 and RUNX1-PRDM16 fusion transcripts in a case of t(1;21)(p36;q22)-positive therapy-related AML.Stevens-Kroef MJ et al

Summary

Fusion gene

RUNX1/PRDM16 RUNX1 (21q22.12) PRDM16 (1p36.32) M t(1;21)(p36;q22)

Note

Subtle cytogenetic abnormality, easy to confuse with a del(21)(q22) , may be missed in poor quality metaphases.
Atlas Image
Partial GTG-banded karyotype of t(1;21)(p36;q22)

Citation

Marian Stevens-Kroef

t(1;21)(p36;q22) RUNX1/PRDM16

Atlas Genet Cytogenet Oncol Haematol. 2006-03-01

Online version: http://atlasgeneticsoncology.org/haematological/1186/t(1;21)(p36;q22)-runx1-prdm16

Historical Card

2000-02-01 t(1;21)(p36;q22) RUNX1/PRDM16 by  Jean-Loup Huret 

Genetics, Dept Medical Information, University of Poitiers, CHU Poitiers Hospital, F-86021 Poitiers, France

External Links