Bone: Subungual exostosis with t(X;6)(q13;q22) COL4A5/COL12A1
2007-07-01 Clelia Tiziana Storlazzi , Fredrik Mertens Affiliation1.Department of Genetics, Microbiology, University of Bari, Bari, Italy (CTS); Department of Clinical Genetics, Lund University Hospital, Lund, Sweden (FM)
Classification
Note
Benign bone-producing neoplasm of unknown cellular origin.
Clinics and Pathology
Phenotype stem cell origin
Unknown.
Embryonic origin
Unknown.
Etiology
Unknown.
Epidemiology
Affects children and young adults.
Clinics
Subungual exostosis usually presents as a slowly growing, painful mass localized dorsomedially in the distal phalanx, and in contrast to osteochondroma, there is usually no continuity with the underlying cortex.
Treatment
Surgical excision, but local recurrences are not uncommon.
Prognosis
Excellent.
Cytogenetics
Partial G-banding karyotype showing chromosomes 6 and X in a case of subungual exostosis. The arrows indicate the breakpoints.
Cytogenetics morphological
t(X;6)(q22;q13-14).
Cytogenetics molecular
A Probe specific for COL12A1 (RP11-815E21) identified the breakpoint in 6q14.1, as it showed splitting signals on der(X) and der(6). On the same chromosomes, these signals colocalized with the signals of RP11-815E21, encompassing the COL4A5 and IRS4 genes in band Xq22.3.
FISH experiment revealing the breakpoint regions on both chromosomes 6 and X on a case of subungual exostosis.
Probes
RP11-815E21 (COL4A5 and IRS4); RP11-1072D13 (COL12A1).
Variants
The breakpoint on chromosome 6 could be centromeric to COL4A5, in an unknown location.
Genes Involved and Proteins
Gene name
COL4A5 (collagen type IV alpha 5 chain)
Location
Xq22.3
Note
It is currently unknown whether any of these two genes is involved in the pathogenesis of subungual exostosis.
Dna rna description
Genomic (chrX:107,569,810-107,827,431). Three transcript variants: isoform 1 (NM_000495), isoform 2 (NM_033380), isoform 3 (NM_03338).
Protein description
Three proteins, respectively encoded by the isoform 1 (695 aa), isoform 2 (1691 aa), and isoform 3 (1688 aa).
Gene name
COL12A1 (collagen type XII alpha 1 chain)
Location
6q13
Dna rna description
Genomic (chr6:75,850,762-75,972,343). Two transcript variants, a long (NM_004370) and a short isoform (NM_080645).
Protein description
Two proteins: 1899 amino acids (aa) and 3063 aa, respectively encoded by the short and long transcript isoforms.
Result of the chromosomal anomaly
Note
No detected fusion gene.
To be Noted
Note
To elucidate how the transcription of these genes is affected by the translocation, further fresh or fresh frozen samples need to be studied.
Article Bibliography
| Pubmed ID | Last Year | Title | Authors |
|---|---|---|---|
| 9885985 | 1999 | Clonal chromosome abnormalities in a so-called Dupuytren's subungual exostosis. | Dal Cin P et al |
| 11712058 | 2001 | Subungual exostosis of the third toe. | Ilyas W et al |
| 10992031 | 2000 | Imaging of osteochondroma: variants and complications with radiologic-pathologic correlation. | Murphey MD et al |
| 16284948 | 2006 | Rearrangement of the COL12A1 and COL4A5 genes in subungual exostosis: molecular cytogenetic delineation of the tumor-specific translocation t(X;6)(q13-14;q22). | Storlazzi CT et al |
| 15252309 | 2004 | Distinct chromosomal rearrangements in subungual (Dupuytren) exostosis and bizarre parosteal osteochondromatous proliferation (Nora lesion). | Zambrano E et al |
Citation
Clelia Tiziana Storlazzi ; Fredrik Mertens
Bone: Subungual exostosis with t(X;6)(q13;q22) COL4A5/COL12A1
Atlas Genet Cytogenet Oncol Haematol. 2007-07-01
Online version: http://atlasgeneticsoncology.org/solid-tumor/5526/bone-subungual-exostosis-with-t(x
