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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.

Read more about gene names and symbols on the About page.

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) (NCBIThis link leads to a site outside Genetics Home Reference.)

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

Where can I find general information about genes?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

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.

See also Understanding Medical Terminology.

References (9 links)


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