The MMP20 gene provides instructions for making a protein called enamelysin, which is essential for normal tooth development. Enamelysin is involved in the formation of enamel, which is the hard, white material that forms the protective outer layer of each tooth. Enamel is composed mainly of mineral crystals. These microscopic crystals are arranged in organized bundles that give enamel its strength and durability.
Certain proteins are needed to shape and organize the crystals as they form, but these proteins must be removed for enamel to harden normally. Enamelysin cuts (cleaves) other proteins involved in enamel formation, such as amelogenin and ameloblastin, into smaller pieces. Cleavage of these proteins makes them easier to remove when they are no longer needed.
Health Conditions Related to Genetic Changes
At least seven mutations in the MMP20 gene have been identified in people with an autosomal recessive form of a disorder of tooth development called amelogenesis imperfecta. Autosomal recessive inheritance means that two copies of the MMP20 gene in each cell are altered. The MMP20 gene mutations involved in this condition prevent cells from producing functional enamelysin. Without this protein's function, amelogenin and other proteins are not cleaved during enamel formation. Because these proteins remain in the enamel, it does not harden during its formation. The resulting enamel is soft and has an abnormal crystal structure. Teeth with this defective enamel are abnormally rough, discolored, and prone to breakage.More About This Health Condition
Other Names for This Gene
- enamel metalloproteinase
- matrix metallopeptidase 20 (enamelysin)
- matrix metalloproteinase 20
Additional Information & Resources
Tests Listed in the Genetic Testing Registry
Scientific Articles on PubMed
Catalog of Genes and Diseases from OMIM
- Gasse B, Karayigit E, Mathieu E, Jung S, Garret A, Huckert M, Morkmued S, Schneider C, Vidal L, Hemmerle J, Sire JY, Bloch-Zupan A. Homozygous and compound heterozygous MMP20 mutations in amelogenesis imperfecta. J Dent Res. 2013 Jul;92(7):598-603. doi: 10.1177/0022034513488393. Epub 2013 Apr 26. Citation on PubMed
- Iwata T, Yamakoshi Y, Hu JC, Ishikawa I, Bartlett JD, Krebsbach PH, Simmer JP. Processing of ameloblastin by MMP-20. J Dent Res. 2007 Feb;86(2):153-7. doi: 10.1177/154405910708600209. Citation on PubMed
- Khan F, Liu H, Reyes A, Witkowska HE, Martinez-Avila O, Zhu L, Li W, Habelitz S. The proteolytic processing of amelogenin by enamel matrix metalloproteinase (MMP-20) is controlled by mineral ions. Biochim Biophys Acta. 2013 Mar;1830(3):2600-7. doi: 10.1016/j.bbagen.2012.11.021. Citation on PubMed or Free article on PubMed Central
- Kim JW, Simmer JP, Hart TC, Hart PS, Ramaswami MD, Bartlett JD, Hu JC. MMP-20 mutation in autosomal recessive pigmented hypomaturation amelogenesis imperfecta. J Med Genet. 2005 Mar;42(3):271-5. doi: 10.1136/jmg.2004.024505. No abstract available. Citation on PubMed or Free article on PubMed Central
- Ozdemir D, Hart PS, Ryu OH, Choi SJ, Ozdemir-Karatas M, Firatli E, Piesco N, Hart TC. MMP20 active-site mutation in hypomaturation amelogenesis imperfecta. J Dent Res. 2005 Nov;84(11):1031-5. doi: 10.1177/154405910508401112. Citation on PubMed or Free article on PubMed Central
- Simmer JP, Hu JC. Expression, structure, and function of enamel proteinases. Connect Tissue Res. 2002;43(2-3):441-9. doi: 10.1080/03008200290001159. Citation on PubMed
- Turk BE, Lee DH, Yamakoshi Y, Klingenhoff A, Reichenberger E, Wright JT, Simmer JP, Komisarof JA, Cantley LC, Bartlett JD. MMP-20 is predominately a tooth-specific enzyme with a deep catalytic pocket that hydrolyzes type V collagen. Biochemistry. 2006 Mar 28;45(12):3863-74. doi: 10.1021/bi052252o. Citation on PubMed or Free article on PubMed Central
- Wang SK, Hu Y, Simmer JP, Seymen F, Estrella NM, Pal S, Reid BM, Yildirim M, Bayram M, Bartlett JD, Hu JC. Novel KLK4 and MMP20 mutations discovered by whole-exome sequencing. J Dent Res. 2013 Mar;92(3):266-71. doi: 10.1177/0022034513475626. Epub 2013 Jan 25. Citation on PubMed or Free article on PubMed Central
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