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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed February 2007

What is the official name of the MMP20 gene?

The official name of this gene is “matrix metallopeptidase 20.”

MMP20 is the gene's official symbol. The MMP20 gene is also known by other names, listed below.

What is the normal function of the MMP20 gene?

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-containing 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.

How are changes in the MMP20 gene related to health conditions?

amelogenesis imperfecta - caused by mutations in the MMP20 gene

At least two mutations in the MMP20 gene have been identified in people with an autosomal recessive form of amelogenesis imperfecta. Autosomal recessive inheritance means that two copies of the MMP20 gene in each cell are altered. Each of the known mutations alters a single DNA building block (base pair) in a critical region of the MMP20 gene, preventing cells from producing any functional enamelysin. Without this protein, amelogenin and other proteins are not cleaved properly during enamel 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.

Where is the MMP20 gene located?

Cytogenetic Location: 11q22.3

Molecular Location on chromosome 11: base pairs 102,576,834 to 102,625,331

The MMP20 gene is located on the long (q) arm of chromosome 11 at position 22.3.

The MMP20 gene is located on the long (q) arm of chromosome 11 at position 22.3.

More precisely, the MMP20 gene is located from base pair 102,576,834 to base pair 102,625,331 on chromosome 11.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about MMP20?

You and your healthcare professional may find the following resources about MMP20 helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the MMP20 gene or gene products?

  • enamel metalloproteinase
  • matrix metallopeptidase 20 (enamelysin)
  • matrix metalloproteinase 20
  • MMP-20

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding MMP20?

amelogenesis ; autosomal ; autosomal recessive ; base pair ; cell ; critical region ; DNA ; enamel ; gene ; inheritance ; mineral ; protein ; recessive

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (


  • Bartlett JD, Simmer JP. Proteinases in developing dental enamel. Crit Rev Oral Biol Med. 1999;10(4):425-41. Review. (
  • 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. (
  • 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. (
  • NCBI Gene (
  • 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. (
  • Simmer JP, Hu JC. Expression, structure, and function of enamel proteinases. Connect Tissue Res. 2002;43(2-3):441-9. Review. (
  • Stephanopoulos G, Garefalaki ME, Lyroudia K. Genes and related proteins involved in amelogenesis imperfecta. J Dent Res. 2005 Dec;84(12):1117-26. Review. (
  • 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. (


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? ( in the Handbook.

Reviewed: February 2007
Published: March 23, 2015