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


Reviewed September 2014

What is the official name of the LAMA3 gene?

The official name of this gene is “laminin subunit alpha 3.”

LAMA3 is the gene's official symbol. The LAMA3 gene is also known by other names, listed below.

What is the normal function of the LAMA3 gene?

The LAMA3 gene provides instructions for making one part (subunit) of a protein called laminin 332 (formerly known as laminin 5). This protein is made up of three subunits, called alpha, beta, and gamma. The LAMA3 gene carries instructions for the alpha subunit; the beta and gamma subunits are produced from other genes. Three versions of the alpha subunit, called alpha-3a, alpha-3b1, and alpha-3b2, are produced from the LAMA3 gene.

Laminins are a group of proteins that regulate cell growth, cell movement (motility), and the attachment of cells to one another (adhesion). They are also involved in the formation and organization of basement membranes, which are thin, sheet-like structures that separate and support cells in many tissues. Laminin 332 has a particularly important role in the basement membrane that underlies the top layer of skin (the epidermis). This membrane gives strength and resiliency to the skin and creates an additional barrier between the body and its surrounding environment. Laminin 332 is a major component of fibers called anchoring filaments, which connect the two layers of the basement membrane and help hold the skin together.

Studies suggest that laminin 332 also has several other functions. This protein appears to be important in the formation of early wound-healing tissues. Additionally, researchers have proposed roles for laminin 332 in the clear outer covering of the eye (the cornea) and in the development of tooth enamel.

The alpha subunit produced from the LAMA3 gene is also part of two other laminin proteins, laminin 311 and laminin 321. These laminins also appear to provide strength to the skin, although they do not play as big a role as laminin 332. In addition, laminin 311 is involved in cell signaling in the lungs and other tissues.

Does the LAMA3 gene share characteristics with other genes?

The LAMA3 gene belongs to a family of genes called LAM (laminins).

A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? ( in the Handbook.

How are changes in the LAMA3 gene related to health conditions?

junctional epidermolysis bullosa - caused by mutations in the LAMA3 gene

More than 30 mutations in the LAMA3 gene have been identified in people with junctional epidermolysis bullosa (JEB). The more severe form of the disease, known as Herlitz JEB, usually results from mutations that prevent the production of any functional laminin 332. Most of these mutations lead to a premature stop signal in the instructions for making all three versions of the alpha subunit, which disrupts the assembly of laminin 332. Without functional laminin 332, the epidermis is only weakly connected to the underlying layers of skin. Friction or other minor trauma (such as rubbing or scratching) can cause the skin layers to separate, leading to the formation of blisters. Infants with Herlitz JEB develop widespread blistering that causes life-threatening complications.

Other LAMA3 gene mutations cause the milder form of junctional epidermolysis bullosa, non-Herlitz JEB. Some of these mutations alter single protein building blocks (amino acids) in the alpha subunit of laminin 332. Others add or delete a small number of amino acids in the alpha subunit or change the way the gene's instructions are used to make the subunit. The genetic changes responsible for milder cases of JEB usually lead to the production of a laminin 332 protein that retains some of its function. Affected individuals experience blistering, but it may be limited to the hands, feet, knees, and elbows.

laryngo-onycho-cutaneous syndrome - caused by mutations in the LAMA3 gene

At least two mutations in the LAMA3 gene have been found to cause laryngo-onycho-cutaneous (LOC) syndrome. This rare disorder is characterized by chronic skin ulcers and the widespread formation of red, bumpy patches called granulation tissue. A buildup of granulation tissue in different parts of the body can lead to serious complications, including vision loss and blockage of the airway. Other features of LOC syndrome include malformed nails and abnormal teeth.

The mutations involved in LOC syndrome lead to an abnormally short version of the alpha-3a subunit of laminin 332; alpha-3b1 and alpha-3b2 are normal. Laminin proteins containing the altered alpha subunit cannot effectively attach the epidermis to underlying layers of skin or regulate wound healing. These abnormalities of laminin 332 cause the chronic skin ulceration and overgrowth of granulation tissue that are characteristic of LOC syndrome. The inability of laminin 332 to perform its other functions leads to the nail and tooth abnormalities that occur in this condition.

LOC syndrome is typically considered a subtype of junctional epidermolysis bullosa (described above). Researchers suggest that LAMA3 gene mutations that affect only the alpha-3a version of the alpha subunit lead to LOC syndrome, while mutations that also affect the other versions of the alpha subunit lead to junctional epidermolysis bullosa.

Where is the LAMA3 gene located?

Cytogenetic Location: 18q11.2

Molecular Location on chromosome 18: base pairs 23,689,443 to 23,955,066

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBI (

The LAMA3 gene is located on the long (q) arm of chromosome 18 at position 11.2.

The LAMA3 gene is located on the long (q) arm of chromosome 18 at position 11.2.

More precisely, the LAMA3 gene is located from base pair 23,689,443 to base pair 23,955,066 on chromosome 18.

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

Where can I find additional information about LAMA3?

You and your healthcare professional may find the following resources about LAMA3 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 LAMA3 gene or gene products?

  • BM600
  • BM600-150kDa
  • BM600 150kD subunit
  • E170
  • epiligrin
  • epiligrin 170 kda subunit
  • epiligrin alpha 3 subunit
  • kalinin-165kDa
  • kalinin 165kD subunit
  • LAM5, alpha-3 subunit
  • lama3a
  • laminin-5 alpha 3 chain
  • laminin 5, alpha-3 subunit
  • laminin A3
  • laminin alpha 3
  • laminin, alpha-3
  • laminin, alpha 3
  • laminin alpha 3 subunit
  • LOCS
  • nicein-150kDa
  • nicein 150kD subunit

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

What glossary definitions help with understanding LAMA3?

acids ; basal lamina ; basement membrane ; basement membranes ; cell ; chronic ; cornea ; cutaneous ; enamel ; epidermis ; gene ; hemidesmosome ; keratinocyte ; protein ; subunit ; syndrome ; tissue ; trauma ; ulceration

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


  • Aumailley M, Bruckner-Tuderman L, Carter WG, Deutzmann R, Edgar D, Ekblom P, Engel J, Engvall E, Hohenester E, Jones JC, Kleinman HK, Marinkovich MP, Martin GR, Mayer U, Meneguzzi G, Miner JH, Miyazaki K, Patarroyo M, Paulsson M, Quaranta V, Sanes JR, Sasaki T, Sekiguchi K, Sorokin LM, Talts JF, Tryggvason K, Uitto J, Virtanen I, von der Mark K, Wewer UM, Yamada Y, Yurchenco PD. A simplified laminin nomenclature. Matrix Biol. 2005 Aug;24(5):326-32. Review. (
  • Barzegar M, Mozafari N, Kariminejad A, Asadikani Z, Ozoemena L, McGrath JA. A new homozygous nonsense mutation in LAMA3A underlying laryngo-onycho-cutaneous syndrome. Br J Dermatol. 2013 Dec;169(6):1353-6. doi: 10.1111/bjd.12522. (
  • Hamill KJ, McLean WH. The alpha-3 polypeptide chain of laminin 5: insight into wound healing responses from the study of genodermatoses. Clin Exp Dermatol. 2005 Jul;30(4):398-404. Review. (
  • Hamill KJ, Paller AS, Jones JC. Adhesion and migration, the diverse functions of the laminin alpha3 subunit. Dermatol Clin. 2010 Jan;28(1):79-87. doi: 10.1016/j.det.2009.10.009. Review. (
  • Hartwig B, Borm B, Schneider H, Arin MJ, Kirfel G, Herzog V. Laminin-5-deficient human keratinocytes: defective adhesion results in a saltatory and inefficient mode of migration. Exp Cell Res. 2007 May 1;313(8):1575-87. Epub 2007 Feb 9. (
  • Kim CC, Liang MG, Pfendner E, Kimonis VE. What syndrome is this? Laryngo-onycho-cutaneous syndrome. Pediatr Dermatol. 2007 May-Jun;24(3):306-8. (
  • McLean WH, Irvine AD, Hamill KJ, Whittock NV, Coleman-Campbell CM, Mellerio JE, Ashton GS, Dopping-Hepenstal PJ, Eady RA, Jamil T, Phillips R, Shabbir SG, Haroon TS, Khurshid K, Moore JE, Page B, Darling J, Atherton DJ, Van Steensel MA, Munro CS, Smith FJ, McGrath JA. An unusual N-terminal deletion of the laminin alpha3a isoform leads to the chronic granulation tissue disorder laryngo-onycho-cutaneous syndrome. Hum Mol Genet. 2003 Sep 15;12(18):2395-409. Epub 2003 Jul 15. Erratum in: Hum Mol Genet. 2004 Feb 1;13(3):365. Phillips Rodney J [corrected to Phillips Roderic J]. (
  • Nakano A, Chao SC, Pulkkinen L, Murrell D, Bruckner-Tuderman L, Pfendner E, Uitto J. Laminin 5 mutations in junctional epidermolysis bullosa: molecular basis of Herlitz vs. non-Herlitz phenotypes. Hum Genet. 2002 Jan;110(1):41-51. Epub 2001 Nov 13. (
  • NCBI Gene (
  • Schneider H, Mühle C, Pacho F. Biological function of laminin-5 and pathogenic impact of its deficiency. Eur J Cell Biol. 2007 Dec;86(11-12):701-17. Epub 2006 Sep 26. (
  • Varki R, Sadowski S, Pfendner E, Uitto J. Epidermolysis bullosa. I. Molecular genetics of the junctional and hemidesmosomal variants. J Med Genet. 2006 Aug;43(8):641-52. Epub 2006 Feb 10. (


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: September 2014
Published: February 1, 2016