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


Reviewed November 2008

What is the official name of the MTTP gene?

The official name of this gene is “microsomal triglyceride transfer protein.”

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

What is the normal function of the MTTP gene?

The MTTP gene provides instructions for making a protein called microsomal triglyceride transfer protein. The microsomal triglyceride transfer protein helps produce beta-lipoproteins, which are molecules that consist of proteins combined with cholesterol and particular types of fats called phospholipids and triglycerides. These beta-lipoproteins contain the protein apolipoprotein B, which is critical for the creation of molecules called chylomicrons. Chylomicrons are formed when dietary fats and cholesterol are absorbed from the intestines. Chylomicrons are also necessary for the absorption of certain fat-soluble vitamins, especially vitamins E, A, and sometimes K.

Other beta-lipoproteins containing apolipoprotein B, particularly low-density lipoproteins (LDL) and very low-density lipoproteins (VLDL), are created by microsomal triglyceride transfer protein in the liver. These lipoproteins transport fats, cholesterol, and fat-soluble vitamins throughout the body in the bloodstream. Sufficient levels of fats, cholesterol, and vitamins are necessary for normal growth, development, and maintenance of the body's cells and tissues, particularly nerve cells and tissues in the eye.

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

abetalipoproteinemia - caused by mutations in the MTTP gene

More than 30 mutations that cause abetalipoproteinemia have been identified in the MTTP gene. One particular mutation is more common in people of Ashkenazi (eastern and central European) Jewish descent; this mutation replaces the protein building block (amino acid) glycine with a stop signal at position 865 (written as Gly865X or G865X). As a result of this amino acid change, an abnormally small, nonfunctional version of the protein is made. Similarly, many other mutations that cause abetalipoproteinemia produce abnormally short microsomal triglyceride transfer proteins. A shortened protein is unable to produce beta-lipoproteins, resulting in a severe deficiency of chylomicrons, low-density lipoproteins, and very low-density lipoproteins. The absence of these lipoproteins prevents dietary fats and fat-soluble vitamins from being absorbed and carried to the rest of the body, leading to the nutritional and neurological problems seen in people with abetalipoproteinemia.

Where is the MTTP gene located?

Cytogenetic Location: 4q24

Molecular Location on chromosome 4: base pairs 99,564,078 to 99,623,997

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

The MTTP gene is located on the long (q) arm of chromosome 4 at position 24.

The MTTP gene is located on the long (q) arm of chromosome 4 at position 24.

More precisely, the MTTP gene is located from base pair 99,564,078 to base pair 99,623,997 on chromosome 4.

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

Where can I find additional information about MTTP?

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

  • ABL
  • microsomal TG transfer protein
  • microsomal triglyceride transfer protein (large polypeptide, 88kD)
  • microsomal triglyceride transfer protein large subunit
  • MTP
  • MTP triglyceride carrier

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

What glossary definitions help with understanding MTTP?

amino acid ; apolipoprotein ; beta-lipoproteins ; carrier ; cholesterol ; chylomicrons ; deficiency ; gene ; glycine ; LDL ; low-density lipoproteins ; mutation ; neurological ; phospholipids ; protein ; soluble ; subunit ; triglycerides ; vitamins ; VLDL

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


  • Benayoun L, Granot E, Rizel L, Allon-Shalev S, Behar DM, Ben-Yosef T. Abetalipoproteinemia in Israel: evidence for a founder mutation in the Ashkenazi Jewish population and a contiguous gene deletion in an Arab patient. Mol Genet Metab. 2007 Apr;90(4):453-7. Epub 2007 Feb 1. (
  • Berriot-Varoqueaux N, Aggerbeck LP, Samson-Bouma M, Wetterau JR. The role of the microsomal triglygeride transfer protein in abetalipoproteinemia. Annu Rev Nutr. 2000;20:663-97. Review. (
  • Hooper AJ, van Bockxmeer FM, Burnett JR. Monogenic hypocholesterolaemic lipid disorders and apolipoprotein B metabolism. Crit Rev Clin Lab Sci. 2005;42(5-6):515-45. Review. (
  • Hussain MM, Iqbal J, Anwar K, Rava P, Dai K. Microsomal triglyceride transfer protein: a multifunctional protein. Front Biosci. 2003 May 1;8:s500-6. Review. (
  • Li CM, Presley JB, Zhang X, Dashti N, Chung BH, Medeiros NE, Guidry C, Curcio CA. Retina expresses microsomal triglyceride transfer protein: implications for age-related maculopathy. J Lipid Res. 2005 Apr;46(4):628-40. Epub 2005 Jan 16. (
  • NCBI Gene (
  • Shelness GS, Ledford AS. Evolution and mechanism of apolipoprotein B-containing lipoprotein assembly. Curr Opin Lipidol. 2005 Jun;16(3):325-32. Review. (
  • Swift LL, Kakkad B, Boone C, Jovanovska A, Jerome WG, Mohler PJ, Ong DE. Microsomal triglyceride transfer protein expression in adipocytes: a new component in fat metabolism. FEBS Lett. 2005 Jun 6;579(14):3183-9. (


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: November 2008
Published: February 8, 2016