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ABCA1 gene

ATP binding cassette subfamily A member 1

Normal Function

The ABCA1 gene belongs to a group of genes called the ATP-binding cassette family. These genes provide instructions for making proteins that transport molecules across cell membranes. The ABCA1 protein is produced in many tissues, but high levels of this protein are found in the liver and in immune cells called macrophages.

The ABCA1 protein helps move cholesterol and certain fats called phospholipids across the cell membrane to the outside of the cell. These substances are then picked up by a protein called apolipoprotein A-I (apoA-I), which is produced from the APOA1 gene. ApoA-I, cholesterol, and phospholipids combine to make high-density lipoprotein (HDL), often referred to as "good cholesterol" because high levels of this substance reduce the chances of developing heart and blood vessel (cardiovascular) disease.

HDL carries cholesterol and phospholipids through the bloodstream from the body's tissues to the liver. Once in the liver, cholesterol and phospholipids are redistributed to other tissues or removed from the body. The process of removing excess cholesterol from cells is extremely important for balancing cholesterol levels and maintaining cardiovascular health.

Health Conditions Related to Genetic Changes

Familial HDL deficiency

Variants (also called mutations) in the ABCA1 gene can cause a condition called familial HDL deficiency. People with this condition have reduced levels of HDL in their blood and may experience early-onset cardiovascular disease, often before age 50. While one copy of the altered ABCA1 gene causes familial HDL deficiency, two copies of the altered gene cause a more severe disorder called Tangier disease (described below).

Most ABCA1 gene variants that cause familial HDL deficiency change single protein building blocks (amino acids) in the ABCA1 protein. Other variants alter the protein in other ways. The changes in the ABCA1 protein prevent the release of cholesterol and phospholipids from cells, decreasing the amount of these substances available to form HDL. As a result, the levels of HDL in the blood are low. A shortage (deficiency) of HDL is believed to increase a person's risk of cardiovascular disease.

More About This Health Condition

Tangier disease

Several variants  in the ABCA1 gene have been found to cause Tangier disease. Most of these variants change single amino acids in the ABCA1 protein. These variants prevent the release of cholesterol and phospholipids from cells. As a result, these substances accumulate within cells, causing certain body tissues to enlarge and the tonsils to acquire a yellowish-orange color. A buildup of cholesterol can be toxic to cells, leading to impaired cell function or cell death. In addition, the inability to transport cholesterol and phospholipids out of cells results in very low HDL levels, which may increase the risk of cardiovascular disease. All these factors cause the signs and symptoms of Tangier disease.

More About This Health Condition

Other Names for This Gene

  • ABC1
  • ATP binding cassette transporter 1
  • ATP-binding cassette 1
  • ATP-binding cassette, sub-family A (ABC1), member 1
  • CERP
  • cholesterol efflux regulatory protein
  • FLJ14958
  • HDLDT1
  • high density lipoprotein deficiency, Tangier type, 1
  • TGD

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases


  • Albrecht C, Viturro E. The ABCA subfamily--gene and protein structures, functions and associated hereditary diseases. Pflugers Arch. 2007 Feb;453(5):581-9. doi: 10.1007/s00424-006-0047-8. Epub 2006 Apr 4. Citation on PubMed
  • Batal R, Tremblay M, Krimbou L, Mamer O, Davignon J, Genest J Jr, Cohn JS. Familial HDL deficiency characterized by hypercatabolism of mature apoA-I but not proapoA-I. Arterioscler Thromb Vasc Biol. 1998 Apr;18(4):655-64. doi: 10.1161/01.atv.18.4.655. Citation on PubMed
  • Bodzioch M, Orso E, Klucken J, Langmann T, Bottcher A, Diederich W, Drobnik W, Barlage S, Buchler C, Porsch-Ozcurumez M, Kaminski WE, Hahmann HW, Oette K, Rothe G, Aslanidis C, Lackner KJ, Schmitz G. The gene encoding ATP-binding cassette transporter 1 is mutated in Tangier disease. Nat Genet. 1999 Aug;22(4):347-51. doi: 10.1038/11914. Citation on PubMed
  • Brooks-Wilson A, Marcil M, Clee SM, Zhang LH, Roomp K, van Dam M, Yu L, Brewer C, Collins JA, Molhuizen HO, Loubser O, Ouelette BF, Fichter K, Ashbourne-Excoffon KJ, Sensen CW, Scherer S, Mott S, Denis M, Martindale D, Frohlich J, Morgan K, Koop B, Pimstone S, Kastelein JJ, Genest J Jr, Hayden MR. Mutations in ABC1 in Tangier disease and familial high-density lipoprotein deficiency. Nat Genet. 1999 Aug;22(4):336-45. doi: 10.1038/11905. Citation on PubMed
  • Brunham LR, Kruit JK, Iqbal J, Fievet C, Timmins JM, Pape TD, Coburn BA, Bissada N, Staels B, Groen AK, Hussain MM, Parks JS, Kuipers F, Hayden MR. Intestinal ABCA1 directly contributes to HDL biogenesis in vivo. J Clin Invest. 2006 Apr;116(4):1052-62. doi: 10.1172/JCI27352. Epub 2006 Mar 16. Citation on PubMed or Free article on PubMed Central
  • Dean M, Moitra K, Allikmets R. The human ATP-binding cassette (ABC) transporter superfamily. Hum Mutat. 2022 Sep;43(9):1162-1182. doi: 10.1002/humu.24418. Epub 2022 Jun 22. Citation on PubMed
  • Iatan I, Alrasadi K, Ruel I, Alwaili K, Genest J. Effect of ABCA1 mutations on risk for myocardial infarction. Curr Atheroscler Rep. 2008 Oct;10(5):413-26. doi: 10.1007/s11883-008-0064-5. Citation on PubMed
  • Kolovou GD, Mikhailidis DP, Anagnostopoulou KK, Daskalopoulou SS, Cokkinos DV. Tangier disease four decades of research: a reflection of the importance of HDL. Curr Med Chem. 2006;13(7):771-82. doi: 10.2174/092986706776055580. Citation on PubMed
  • Marcil M, Brooks-Wilson A, Clee SM, Roomp K, Zhang LH, Yu L, Collins JA, van Dam M, Molhuizen HO, Loubster O, Ouellette BF, Sensen CW, Fichter K, Mott S, Denis M, Boucher B, Pimstone S, Genest J Jr, Kastelein JJ, Hayden MR. Mutations in the ABC1 gene in familial HDL deficiency with defective cholesterol efflux. Lancet. 1999 Oct 16;354(9187):1341-6. doi: 10.1016/s0140-6736(99)07026-9. Citation on PubMed
  • Mott S, Yu L, Marcil M, Boucher B, Rondeau C, Genest J Jr. Decreased cellular cholesterol efflux is a common cause of familial hypoalphalipoproteinemia: role of the ABCA1 gene mutations. Atherosclerosis. 2000 Oct;152(2):457-68. doi: 10.1016/s0021-9150(99)00498-0. Citation on PubMed
  • Oram JF. HDL apolipoproteins and ABCA1: partners in the removal of excess cellular cholesterol. Arterioscler Thromb Vasc Biol. 2003 May 1;23(5):720-7. doi: 10.1161/01.ATV.0000054662.44688.9A. Epub 2003 Jan 9. Citation on PubMed
  • Rust S, Rosier M, Funke H, Real J, Amoura Z, Piette JC, Deleuze JF, Brewer HB, Duverger N, Denefle P, Assmann G. Tangier disease is caused by mutations in the gene encoding ATP-binding cassette transporter 1. Nat Genet. 1999 Aug;22(4):352-5. doi: 10.1038/11921. Citation on PubMed
  • Tall AR, Yvan-Charvet L, Terasaka N, Pagler T, Wang N. HDL, ABC transporters, and cholesterol efflux: implications for the treatment of atherosclerosis. Cell Metab. 2008 May;7(5):365-75. doi: 10.1016/j.cmet.2008.03.001. Citation on PubMed
  • Tang C, Oram JF. The cell cholesterol exporter ABCA1 as a protector from cardiovascular disease and diabetes. Biochim Biophys Acta. 2009 Jul;1791(7):563-72. doi: 10.1016/j.bbalip.2009.03.011. Epub 2009 Apr 1. Citation on PubMed

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.