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ABCA12 gene

ATP binding cassette subfamily A member 12
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Normal Function

The ABCA12 gene provides instructions for making a protein known as an ATP-binding cassette (ABC) transporter. ABC transporter proteins carry many types of molecules across cell membranes. In particular, the ABCA12 protein plays a major role in transporting fats (lipids) in cells that make up the outermost layer of skin (the epidermis). This lipid transport is needed to maintain the layers of lipids within the epidermis that are necessary to prevent water loss (dehydration) and for normal development of the skin. The ABCA12 protein is also found in several other tissues, including the testes, placenta, lungs, stomach, fetal brain, and liver.

Health Conditions Related to Genetic Changes

Harlequin ichthyosis

More than 65 mutations in the ABCA12 gene have been identified in people with harlequin ichthyosis. This skin condition is characterized by hard, thick scales that are present at birth; excessive dehydration; and increased risk of infections. Most of the mutations lead to an absence of ABCA12 protein or the production of an extremely small version of the protein that cannot transport lipids properly. A lack of lipid transport causes numerous problems with the development of the epidermis before and after birth. Specifically, it prevents the skin from forming an effective barrier against dehydration, and leads to the skin problems characteristic of harlequin ichthyosis.

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Nonbullous congenital ichthyosiform erythroderma

At least 20 mutations in the ABCA12 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 dehydration. These skin abnormalities tend to be less severe than those in harlequin ichthyosis (described above). Most of the mutations that cause NBCIE change single amino acids in the ABCA12 protein. These mutations likely lead to the production of a protein with reduced function, which impairs lipid transport and the formation of the lipid layers within the epidermis. Problems with this protective barrier underlie the skin abnormalities and other features of NBCIE.

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Lamellar ichthyosis

MedlinePlus Genetics provides information about Lamellar ichthyosis

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Other Names for This Gene

  • ATP-binding cassette 12
  • ATP-binding cassette transporter 12
  • ATP-binding cassette, sub-family A (ABC1), member 12
  • ATP-binding cassette, sub-family A, member 12
  • ICR2B

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Research Resources


  • Akiyama M, Sugiyama-Nakagiri Y, Sakai K, McMillan JR, Goto M, Arita K, Tsuji-Abe Y, Tabata N, Matsuoka K, Sasaki R, Sawamura D, Shimizu H. Mutations in lipid transporter ABCA12 in harlequin ichthyosis and functional recovery by corrective gene transfer. J Clin Invest. 2005 Jul;115(7):1777-84. Citation on PubMed or Free article on PubMed Central
  • Akiyama M. Pathomechanisms of harlequin ichthyosis and ABCA transporters in human diseases. Arch Dermatol. 2006 Jul;142(7):914-8. Review. Citation on PubMed
  • Hovnanian A. Harlequin ichthyosis unmasked: a defect of lipid transport. J Clin Invest. 2005 Jul;115(7):1708-10. Review. Citation on PubMed or Free article on PubMed Central
  • Kelsell DP, Norgett EE, Unsworth H, Teh MT, Cullup T, Mein CA, Dopping-Hepenstal PJ, Dale BA, Tadini G, Fleckman P, Stephens KG, Sybert VP, Mallory SB, North BV, Witt DR, Sprecher E, Taylor AE, Ilchyshyn A, Kennedy CT, Goodyear H, Moss C, Paige D, Harper JI, Young BD, Leigh IM, Eady RA, O'Toole EA. Mutations in ABCA12 underlie the severe congenital skin disease harlequin ichthyosis. Am J Hum Genet. 2005 May;76(5):794-803. Epub 2005 Mar 8. Citation on PubMed or Free article on PubMed Central
  • LefĂ©vre C, Audebert S, Jobard F, Bouadjar B, Lakhdar H, Boughdene-Stambouli O, Blanchet-Bardon C, Heilig R, Foglio M, Weissenbach J, Lathrop M, Prud'homme JF, Fischer J. Mutations in the transporter ABCA12 are associated with lamellar ichthyosis type 2. Hum Mol Genet. 2003 Sep 15;12(18):2369-78. Epub 2003 Jul 15. Citation on PubMed
  • Nawaz S, Tariq M, Ahmad I, Malik NA, Baig SM, Dahl N, Klar J. Non-bullous congentital ichthyosiform erythroderma associated with homozygosity for a novel missense mutation in an ATP binding domain of ABCA12. Eur J Dermatol. 2012 Mar-Apr;22(2):178-81. doi: 10.1684/ejd.2011.1638. Citation on PubMed
  • Sakai K, Akiyama M, Yanagi T, McMillan JR, Suzuki T, Tsukamoto K, Sugiyama H, Hatano Y, Hayashitani M, Takamori K, Nakashima K, Shimizu H. ABCA12 is a major causative gene for non-bullous congenital ichthyosiform erythroderma. J Invest Dermatol. 2009 Sep;129(9):2306-9. doi: 10.1038/jid.2009.23. Epub 2009 Mar 5. Citation on PubMed
  • Thomas AC, Cullup T, Norgett EE, Hill T, Barton S, Dale BA, Sprecher E, Sheridan E, Taylor AE, Wilroy RS, DeLozier C, Burrows N, Goodyear H, Fleckman P, Stephens KG, Mehta L, Watson RM, Graham R, Wolf R, Slavotinek A, Martin M, Bourn D, Mein CA, O'Toole EA, Kelsell DP. ABCA12 is the major harlequin ichthyosis gene. J Invest Dermatol. 2006 Nov;126(11):2408-13. Epub 2006 Aug 10. Citation on PubMed
  • Thomas AC, Sinclair C, Mahmud N, Cullup T, Mellerio JE, Harper J, Dale BA, Turc-Carel C, Hohl D, McGrath JA, Vahlquist A, Hellstrom-Pigg M, Ganemo A, Metcalfe K, Mein CA, O'Toole EA, Kelsell DP. Novel and recurring ABCA12 mutations associated with harlequin ichthyosis: implications for prenatal diagnosis. Br J Dermatol. 2008 Mar;158(3):611-3. Epub 2007 Nov 6. Citation on PubMed
  • Uitto J. The gene family of ABC transporters--novel mutations, new phenotypes. Trends Mol Med. 2005 Aug;11(8):341-3. Review. Citation on PubMed
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