2k8p

Structural highlights

Disease

[SOST_HUMAN] Defects in SOST are the cause of sclerosteosis type 1 (SOST1) [MIM:269500]. An autosomal recessive sclerosing bone dysplasia characterized by a generalized hyperostosis and sclerosis leading to a markedly thickened skull, with mandible, ribs, clavicles and all long bones also being affected. Due to narrowing of the foramina of the cranial nerves, facial nerve palsy, hearing loss and atrophy of the optic nerves can occur. Sclerosteosis is clinically and radiologically very similar to van Buchem disease, mainly differentiated by hand malformations and a large stature in sclerosteosis patients.^{[1] [2] [3]} Defects in SOST are a cause of van Buchem disease (VBCH) [MIM:239100]. An autosomal recessive sclerosing bone dysplasia characterized by endosteal hyperostosis of the mandible, skull, ribs, clavicles, and diaphyses of the long bones. Affected patients present a symmetrically increased thickness of bones, most frequently found as an enlarged jawbone, but also an enlargement of the skull, ribs, diaphysis of long bones, as well as tubular bones of hands and feet. The clinical consequence of increased thickness of the skull include facial nerve palsy causing hearing loss, visual problems, neurological pain, and, very rarely, blindness as a consequence of optic atrophy. Serum alkaline phosphatase levels are elevated. Note=A 52 kb deletion downstream of SOST results in SOST transcription suppression causing van Buchem disease.^[4] Defects in SOST are a cause of craniodiaphyseal dysplasia autosomal dominant (CDD) [MIM:122860]. A severe bone dysplasia characterized by massive generalized hyperostosis and sclerosis, especially involving the skull and facial bones. The sclerosis is so severe that the resulting facial distortion is referred to as 'leontiasis ossea' (leonine faces) and the bone deposition results in progressive stenosis of craniofacial foramina. Respiratory obstruction due to choanal stenosis compromises the clinical outcomes of affected patients. Note=Heterozygous mutations located in the secretion signal of the SOST gene prevent sclerostin secretion and can be responsible for craniodiaphyseal dysplasia.^[5]

Function

[SOST_HUMAN] Negative regulator of bone growth that acts through inhibition of Wnt signaling and bone formation.^[6]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

References

1. ↑ Balemans W, Ebeling M, Patel N, Van Hul E, Olson P, Dioszegi M, Lacza C, Wuyts W, Van Den Ende J, Willems P, Paes-Alves AF, Hill S, Bueno M, Ramos FJ, Tacconi P, Dikkers FG, Stratakis C, Lindpaintner K, Vickery B, Foernzler D, Van Hul W. Increased bone density in sclerosteosis is due to the deficiency of a novel secreted protein (SOST). Hum Mol Genet. 2001 Mar 1;10(5):537-43. PMID:11181578
2. ↑ Brunkow ME, Gardner JC, Van Ness J, Paeper BW, Kovacevich BR, Proll S, Skonier JE, Zhao L, Sabo PJ, Fu Y, Alisch RS, Gillett L, Colbert T, Tacconi P, Galas D, Hamersma H, Beighton P, Mulligan J. Bone dysplasia sclerosteosis results from loss of the SOST gene product, a novel cystine knot-containing protein. Am J Hum Genet. 2001 Mar;68(3):577-89. Epub 2001 Feb 9. PMID:11179006
3. ↑ Piters E, Culha C, Moester M, Van Bezooijen R, Adriaensen D, Mueller T, Weidauer S, Jennes K, de Freitas F, Lowik C, Timmermans JP, Van Hul W, Papapoulos S. First missense mutation in the SOST gene causing sclerosteosis by loss of sclerostin function. Hum Mutat. 2010 Jul;31(7):E1526-43. doi: 10.1002/humu.21274. PMID:20583295 doi:10.1002/humu.21274
4. ↑ Balemans W, Patel N, Ebeling M, Van Hul E, Wuyts W, Lacza C, Dioszegi M, Dikkers FG, Hildering P, Willems PJ, Verheij JB, Lindpaintner K, Vickery B, Foernzler D, Van Hul W. Identification of a 52 kb deletion downstream of the SOST gene in patients with van Buchem disease. J Med Genet. 2002 Feb;39(2):91-7. PMID:11836356
5. ↑ Kim SJ, Bieganski T, Sohn YB, Kozlowski K, Semenov M, Okamoto N, Kim CH, Ko AR, Ahn GH, Choi YL, Park SW, Ki CS, Kim OH, Nishimura G, Unger S, Superti-Furga A, Jin DK. Identification of signal peptide domain SOST mutations in autosomal dominant craniodiaphyseal dysplasia. Hum Genet. 2011 May;129(5):497-502. doi: 10.1007/s00439-011-0947-3. Epub 2011 Jan, 9. PMID:21221996 doi:10.1007/s00439-011-0947-3
6. ↑ Semenov M, Tamai K, He X. SOST is a ligand for LRP5/LRP6 and a Wnt signaling inhibitor. J Biol Chem. 2005 Jul 22;280(29):26770-5. Epub 2005 May 20. PMID:15908424 doi:10.1074/jbc.M504308200
7. ↑ Veverka V, Henry AJ, Slocombe PM, Ventom A, Mulloy B, Muskett FW, Muzylak M, Greenslade K, Moore A, Zhang L, Gong J, Qian X, Paszty C, Taylor RJ, Robinson MK, Carr MD. Characterization of the structural features and interactions of sclerostin: molecular insight into a key regulator of Wnt-mediated bone formation. J Biol Chem. 2009 Apr 17;284(16):10890-900. Epub 2009 Feb 10. PMID:19208630 doi:10.1074/jbc.M807994200