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Genetics Home Reference: your guide to understanding genetic conditions
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CPT1A

Reviewed November 2010

What is the official name of the CPT1A gene?

The official name of this gene is “carnitine palmitoyltransferase 1A (liver).”

CPT1A is the gene's official symbol. The CPT1A gene is also known by other names, listed below.

What is the normal function of the CPT1A gene?

The CPT1A gene provides instructions for making an enzyme called carnitine palmitoyltransferase 1A, which is found in the liver. This enzyme is essential for fatty acid oxidation, a multistep process that breaks down (metabolizes) fats and converts them into energy. Fatty acid oxidation takes place within mitochondria, which are the energy-producing centers in cells. A group of fats called long-chain fatty acids cannot enter mitochondria unless they are attached to a substance known as carnitine. Carnitine palmitoyltransferase 1A connects carnitine to long-chain fatty acids so they can cross the inner membrane of mitochondria. Once these fatty acids are inside mitochondria, carnitine is removed and they can be metabolized to produce energy. During periods of fasting, long-chain fatty acids are an important energy source for the liver and other tissues.

How are changes in the CPT1A gene related to health conditions?

carnitine palmitoyltransferase I deficiency - caused by mutations in the CPT1A gene

More than 20 mutations in the CPT1A gene have been found to cause carnitine palmitoyltransferase I (CPT I) deficiency. Most of these mutations change single protein building blocks (amino acids) within carnitine palmitoyltransferase 1A. Mutations in the CPT1A gene severely reduce or eliminate the activity of this enzyme. Without enough of this enzyme, carnitine is not attached to long-chain fatty acids. As a result, these fatty acids cannot enter mitochondria and be converted into energy. Reduced energy production can lead to some of the features of CPT I deficiency, such as low blood sugar (hypoglycemia) and low levels of the products of fat breakdown (hypoketosis). Fatty acids may also build up in cells and damage the liver, heart, and brain. This abnormal buildup causes the other signs and symptoms of the disorder.

other disorders - associated with the CPT1A gene

CPT1A gene mutations appear to increase the risk of a serious liver disorder that can develop in women during pregnancy. This disorder, called acute fatty liver of pregnancy, begins with abdominal pain and can rapidly progress to liver failure. Signs of acute fatty liver of pregnancy include an abnormal accumulation of fat in the liver, hypoglycemia, increased levels of ammonia in the blood (hyperammonemia), and abnormalities in liver enzymes. A small percentage of women who have a mutation in one copy of the CPT1A gene in each cell and are carrying a fetus with mutations in both copies of the CPT1A gene develop this maternal liver disease. Little is known about the relationship between CPT1A gene mutations and liver problems in the mother during pregnancy.

Where is the CPT1A gene located?

Cytogenetic Location: 11q13.2

Molecular Location on chromosome 11: base pairs 68,754,619 to 68,841,930

The CPT1A gene is located on the long (q) arm of chromosome 11 at position 13.2.

The CPT1A gene is located on the long (q) arm of chromosome 11 at position 13.2.

More precisely, the CPT1A gene is located from base pair 68,754,619 to base pair 68,841,930 on chromosome 11.

See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.

Where can I find additional information about CPT1A?

You and your healthcare professional may find the following resources about CPT1A 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 CPT1A gene or gene products?

  • carnitine palmitoyltransferase I, liver
  • CPT1
  • CPT1A_HUMAN
  • CPT1-L
  • L-CPT1

See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What glossary definitions help with understanding CPT1A?

acids ; acute ; ammonia ; breakdown ; carnitine ; cell ; deficiency ; enzyme ; fasting ; fatty acids ; fatty liver ; fetus ; gene ; hyperammonemia ; hypoglycemia ; liver failure ; maternal ; mitochondria ; mutation ; oxidation ; protein

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

References

  • Akkaoui M, Cohen I, Esnous C, Lenoir V, Sournac M, Girard J, Prip-Buus C. Modulation of the hepatic malonyl-CoA-carnitine palmitoyltransferase 1A partnership creates a metabolic switch allowing oxidation of de novo fatty acids. Biochem J. 2009 May 27;420(3):429-38. doi: 10.1042/BJ20081932. (http://www.ncbi.nlm.nih.gov/pubmed/19302064?dopt=Abstract)
  • Bennett MJ, Boriack RL, Narayan S, Rutledge SL, Raff ML. Novel mutations in CPT 1A define molecular heterogeneity of hepatic carnitine palmitoyltransferase I deficiency. Mol Genet Metab. 2004 May;82(1):59-63. (http://www.ncbi.nlm.nih.gov/pubmed/15110323?dopt=Abstract)
  • Bonnefont JP, Djouadi F, Prip-Buus C, Gobin S, Munnich A, Bastin J. Carnitine palmitoyltransferases 1 and 2: biochemical, molecular and medical aspects. Mol Aspects Med. 2004 Oct-Dec;25(5-6):495-520. Review. (http://www.ncbi.nlm.nih.gov/pubmed/15363638?dopt=Abstract)
  • Brown NF, Mullur RS, Subramanian I, Esser V, Bennett MJ, Saudubray JM, Feigenbaum AS, Kobari JA, Macleod PM, McGarry JD, Cohen JC. Molecular characterization of L-CPT I deficiency in six patients: insights into function of the native enzyme. J Lipid Res. 2001 Jul;42(7):1134-42. (http://www.ncbi.nlm.nih.gov/pubmed/11441142?dopt=Abstract)
  • OMIM: CARNITINE PALMITOYLTRANSFERASE I, LIVER (http://omim.org/entry/600528)
  • Gene Review: Carnitine Palmitoyltransferase 1A Deficiency (http://www.ncbi.nlm.nih.gov/books/NBK1527)
  • Gobin S, Bonnefont JP, Prip-Buus C, Mugnier C, Ferrec M, Demaugre F, Saudubray JM, Rostane H, Djouadi F, Wilcox W, Cederbaum S, Haas R, Nyhan WL, Green A, Gray G, Girard J, Thuillier L. Organization of the human liver carnitine palmitoyltransferase 1 gene ( CPT1A) and identification of novel mutations in hypoketotic hypoglycaemia. Hum Genet. 2002 Aug;111(2):179-89. Epub 2002 Jul 16. (http://www.ncbi.nlm.nih.gov/pubmed/12189492?dopt=Abstract)
  • Gobin S, Thuillier L, Jogl G, Faye A, Tong L, Chi M, Bonnefont JP, Girard J, Prip-Buus C. Functional and structural basis of carnitine palmitoyltransferase 1A deficiency. J Biol Chem. 2003 Dec 12;278(50):50428-34. Epub 2003 Sep 29. (http://www.ncbi.nlm.nih.gov/pubmed/14517221?dopt=Abstract)
  • Longo N, Amat di San Filippo C, Pasquali M. Disorders of carnitine transport and the carnitine cycle. Am J Med Genet C Semin Med Genet. 2006 May 15;142C(2):77-85. Review. (http://www.ncbi.nlm.nih.gov/pubmed/16602102?dopt=Abstract)
  • NCBI Gene (http://www.ncbi.nlm.nih.gov/gene/1374)
  • Prasad C, Johnson JP, Bonnefont JP, Dilling LA, Innes AM, Haworth JC, Beischel L, Thuillier L, Prip-Buus C, Singal R, Thompson JR, Prasad AN, Buist N, Greenberg CR. Hepatic carnitine palmitoyl transferase 1 (CPT1 A) deficiency in North American Hutterites (Canadian and American): evidence for a founder effect and results of a pilot study on a DNA-based newborn screening program. Mol Genet Metab. 2001 May;73(1):55-63. (http://www.ncbi.nlm.nih.gov/pubmed/11350183?dopt=Abstract)
  • Ramsay RR, Zammit VA. Carnitine acyltransferases and their influence on CoA pools in health and disease. Mol Aspects Med. 2004 Oct-Dec;25(5-6):475-93. Review. (http://www.ncbi.nlm.nih.gov/pubmed/15363637?dopt=Abstract)

 

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? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: November 2010
Published: May 4, 2015