*602411
EXOSTOSIN-LIKE 2; EXTL2

Alternative titles; symbols
MULTIPLE EXOSTOSES-LIKE 2
EXT-RELATED GENE 2; EXTR2

HGNC Approved Gene Symbol: EXTL2

Cytogenetic location: 1p21.2     Genomic coordinates (GRCh37): 1:101,337,940 - 101,360,417 (from NCBI)

TEXT
In patients with multiple exostoses (see 133700), mutations in 2 different genes have been found: EXT1 (608177) on 8q and EXT2 (608210) on 11p. In addition, linkage has demonstrated a third locus, EXT3 (600209), on 19p as the site of mutations causing multiple exostoses. The family of EXT genes was extended by the identification of an EXT-like gene (EXTL1; 601738) showing a high degree of homology with the EXT genes. Wuyts et al. (1997) described a second EXT-like gene, EXTL2, that is homologous to the EXT and EXTL genes. EXTL2 was found to consist of 5 exons encoding a ubiquitously expressed 330-amino acid protein. In addition, a putative pseudogene, EXTL2P, was identified. Saito et al. (1998) also cloned an EXTL2 cDNA, which they called EXTR2. By Northern blot analysis, they detected a 3.4-kb transcript in all tissues tested except leukocyte, where the gene was hardly transcribed. Its expression was relatively constant among tissues, but was weak in liver, lung, and thymus.

By fluorescence in situ hybridization, Wuyts et al. (1997) mapped the EXTL2 gene to 1p12-p11 and the EXTL2 pseudogene to 2q24-q31. By somatic cell hybrid and radiation hybrid analyses, Saito et al. (1998) mapped the EXTL2 gene to chromosome 1p21.

Wuyts and Van Hul (2000) cloned mouse Extl2, which has the same genomic structure as the human gene, encodes a protein identical in size, and has a sequence that is 87% identical to the human sequence. By radiation hybrid analysis, they mapped the mouse gene to chromosome 3.

REFERENCES
1. Saito, T., Seki, N., Yamauchi, M., Tsuji, S., Hayashi, A., Kozuma, S., Hori, T. Structure, chromosomal location, and expression profile of EXTR1 and EXTR2, new members of the multiple exostoses gene family. Biochem. Biophys. Res. Commun. 243: 61-66, 1998. [PubMed: 9473480, related citations] [Full Text: Elsevier Science, Pubget]

2. Wuyts, W., Van Hul, W. Characterization and genomic localization of the mouse Extl2 gene. Cytogenet. Cell Genet. 89: 185-188, 2000. [PubMed: 10965119, related citations] [Full Text: S. Karger AG, Basel, Switzerland, Pubget]

3. Wuyts, W., Van Hul, W., Hendrickx, J., Speleman, F., Wauters, J., De Boulle, K., Van Roy, N., Van Agtmael, T., Bossuyt, P., Willems, P. J. Identification and characterization of a novel member of the EXT gene family, EXTL2. Europ. J. Hum. Genet. 5: 382-389, 1997. [PubMed: 9450183, related citations] [Full Text: Pubget]

Contributors: Carol A. Bocchini - updated : 5/29/2001
Paul J. Converse - updated : 10/31/2000
Creation Date: Victor A. McKusick : 3/2/1998
Edit History: ckniffin : 10/30/2003
mcapotos : 5/30/2001
carol : 5/29/2001
carol : 3/19/2001
mgross : 10/31/2000
mark : 3/2/1998
mark : 3/2/1998