t(X;11)(q21;q23) BRWD3/ARHGAP20

2006-08-01   Claudia Kalla  

1.DKFZ, Div. Molecular Genetics (B060), Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany

Clinics and Pathology

Disease

B-cell chronic lymphocytic leukemia (B-CLL)

Epidemiology

Only one case reported to date. In a second B-CLL case, a variant translocation t(11;13)(q23;q14) rearranged the same gene on 11q23 with another partner.

Cytogenetics

Atlas Image
Dual-color interphase FISH analysis of the 11q23 and Xq21 breakpoints with BAC clones.
(A) FISH analysis with 11q23 specific BACs: RP11-468P24 (red signals) and RP11-206G12 (green signals). Three red signals indicate translocation within the genomic region represented by RP11-468P24.
(B) FISH analysis with the 11q23 specific BAC RP11-264L21 (green signals) and the Xq21 BAC RP11-325E14 (red signals). In the right cell, colocalization of one red and one of the three green signals indicates transfer of 11q23 sequences to Xq21 (white arrow).

Variants

t(11;13)(q23;q14) is a variant translocation that rearranged ARHGAP20 with a novel gene on 13q14 (unpublished data).

Genes Involved and Proteins

Gene name
BRWD3 (bromodomain and WD repeat domain containing 3)
Location
Xq21.1
Note
BRWD3 had been originally mapped to Xq13.3
Dna rna description
5 telomeric --> 3 centromeric orientation; 44 exons spanning 132.7 kb genomic DNA; mRNA coding sequence: 4.2-5.4 kb
Protein description
Contains eight tandem WD40 repeats and two bromodomains; involved in the JAK/STAT signalling cascade.
Gene name
ARHGAP20 (Rho GTPase activating protein 20)
Location
11q23.1
Dna rna description
5 telomeric --> 3 centromeric orientation; 19 exons spanning 136.1 kb genomic DNA; mRNA coding sequence: 3.5-3.6 kb.
Protein description
Contains a RhoGAP domain in combination with PH and RA modules; involved in the regulation of Rho-family GTPases (e.g. regulating the neurite outhgrowth); cytoplasmic localisation.

Result of the Chromosomal Anomaly

Atlas Image
Schematic representation of the ARHGAP20-BRWD3 gene rearrangement. Black ovals represent the centromeres. The gene loci and orientation of ARHGAP20 and BRWD3 and their promoter regions are indicated by red and green arrows and boxes, respectively. Black arrows and the dashed line indicate the position of the breakpoints.

Description

der(11): 5 BRWD3 (exons 1-22) - 3 ARHGAP20 (exons 1e-15);
der(X): 5 ARHGAP20 (promoter-part of exon 1e) - 3 BRWD3 (exons 23-41);
BRWD3 and ARHGAP20 are in the same transcriptional directions, fusion transcripts, however, were not detected.

Note

No fusion transcript expressed.

Article Bibliography

Pubmed IDLast YearTitleAuthors
155436022005Translocation t(X;11)(q13;q23) in B-cell chronic lymphocytic leukemia disrupts two novel genes.Kalla C et al

Citation

Claudia Kalla

t(X;11)(q21;q23) BRWD3/ARHGAP20

Atlas Genet Cytogenet Oncol Haematol. 2006-08-01

Online version: http://atlasgeneticsoncology.org/haematological/1430/t(x;11)(q21;q23)