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ALOX12B gene

arachidonate 12-lipoxygenase, 12R type
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Normal Function

The ALOX12B gene provides instructions for making an enzyme called 12R-LOX. This enzyme is part of a family of enzymes called arachidonate lipoxygenases. Most of these enzymes help add an oxygen molecule to a particular fatty acid called arachidonic acid. Arachidonate lipoxygenases add oxygen molecules at different locations on the arachidonic acid molecule, producing a variety of substances called fatty acid hydroperoxides. The fatty acid hydroperoxides are then processed into molecules that play an important role in chemical signaling within cells.

Specifically, the 12R-LOX enzyme helps add an oxygen molecule to arachidonic acid to make a substance called 12R-hydroperoxyeicosatetraenoic acid (12R-HPETE). 12R-HPETE is later converted to a signaling molecule that is involved in the formation of the layers of fats (lipids) within the outermost layer of the skin (the epidermis). The lipid layers are necessary to prevent water loss (dehydration) through the skin.

Health Conditions Related to Genetic Changes

Nonbullous congenital ichthyosiform erythroderma

More than 55 mutations in the ALOX12B gene have been found to cause nonbullous congenital ichthyosiform erythroderma (NBCIE). This condition affects the skin and causes redness; the development of fine, white scales; an increased risk of infections; and excessive dehydration. Most of the mutations change single protein building blocks (amino acids) in the 12R-LOX enzyme. Many ALOX12B gene mutations lead to the production of a nonfunctional 12R-LOX enzyme, which disrupts the processing of the molecules involved in the formation of the lipid layer within the epidermis. Problems with this protective barrier underlie the skin abnormalities and other features of NBCIE.

More About This Health Condition

Other disorders

ALOX12B gene mutations have been found to cause another form of ichthyosis called self-healing collodion baby. Individuals with this condition are born with a tight, clear sheath covering their skin called a collodion membrane, which is usually shed during the first few weeks of life. While babies with NBCIE (described above) may also be born with a collodion membrane, infants with self-healing collodion baby often show normal or near normal skin within a few months.

Only a few people with self-healing collodion baby have been found to have ALOX12B gene mutations; the majority of cases are caused by mutations in other genes.

Other Names for This Gene

  • 12R-lipoxygenase
  • 12R-LOX
  • arachidonate 12-lipoxygenase, 12R-type
  • epidermis-type lipoxygenase 12
  • LX12B_HUMAN

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Research Resources

References

  • Eckl KM, de Juanes S, Kurtenbach J, Nätebus M, Lugassy J, Oji V, Traupe H, Preil ML, Martínez F, Smolle J, Harel A, Krieg P, Sprecher E, Hennies HC. Molecular analysis of 250 patients with autosomal recessive congenital ichthyosis: evidence for mutation hotspots in ALOXE3 and allelic heterogeneity in ALOX12B. J Invest Dermatol. 2009 Jun;129(6):1421-8. doi: 10.1038/jid.2008.409. Epub 2009 Jan 8. Citation on PubMed
  • Eckl KM, Krieg P, Küster W, Traupe H, André F, Wittstruck N, Fürstenberger G, Hennies HC. Mutation spectrum and functional analysis of epidermis-type lipoxygenases in patients with autosomal recessive congenital ichthyosis. Hum Mutat. 2005 Oct;26(4):351-61. Citation on PubMed
  • Harting M, Brunetti-Pierri N, Chan CS, Kirby J, Dishop MK, Richard G, Scaglia F, Yan AC, Levy ML. Self-healing collodion membrane and mild nonbullous congenital ichthyosiform erythroderma due to 2 novel mutations in the ALOX12B gene. Arch Dermatol. 2008 Mar;144(3):351-6. doi: 10.1001/archderm.144.3.351. Citation on PubMed
  • Jobard F, Lefèvre C, Karaduman A, Blanchet-Bardon C, Emre S, Weissenbach J, Ozgüc M, Lathrop M, Prud'homme JF, Fischer J. Lipoxygenase-3 (ALOXE3) and 12(R)-lipoxygenase (ALOX12B) are mutated in non-bullous congenital ichthyosiform erythroderma (NCIE) linked to chromosome 17p13.1. Hum Mol Genet. 2002 Jan 1;11(1):107-13. Citation on PubMed
  • Krieg P, Fürstenberger G. The role of lipoxygenases in epidermis. Biochim Biophys Acta. 2014 Mar;1841(3):390-400. doi: 10.1016/j.bbalip.2013.08.005. Epub 2013 Aug 16. Review. Erratum in: Biochim Biophys Acta. 2014 Dec;1841(12):1767. Citation on PubMed
  • Mashima R, Okuyama T. The role of lipoxygenases in pathophysiology; new insights and future perspectives. Redox Biol. 2015 Dec;6:297-310. doi: 10.1016/j.redox.2015.08.006. Epub 2015 Aug 7. Review. Citation on PubMed or Free article on PubMed Central
  • Yu Z, Schneider C, Boeglin WE, Brash AR. Mutations associated with a congenital form of ichthyosis (NCIE) inactivate the epidermal lipoxygenases 12R-LOX and eLOX3. Biochim Biophys Acta. 2005 Jan 5;1686(3):238-47. Citation on PubMed
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