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Reviewed June 2015

What is the official name of the GAMT gene?

The official name of this gene is “guanidinoacetate N-methyltransferase.”

GAMT is the gene's official symbol. The GAMT 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 GAMT gene?

The GAMT gene provides instructions for making the enzyme guanidinoacetate methyltransferase, which is active (expressed) mainly in the liver. This enzyme participates in the two-step production (synthesis) of the compound creatine from the protein building blocks (amino acids) glycine, arginine, and methionine. Specifically, guanidinoacetate methyltransferase controls the second step of this process. In this step, creatine is produced from another compound called guanidinoacetate. Creatine is needed for the body to store and use energy properly. It is involved in providing energy for muscle contraction, and is also important in nervous system functioning.

In addition to its role in creatine synthesis, the guanidinoacetate methyltransferase enzyme is thought to help activate a process called fatty acid oxidation. This process provides an energy source for cells during times of stress when their normal fuel, the simple sugar glucose, is scarce.

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

guanidinoacetate methyltransferase deficiency - caused by mutations in the GAMT gene

At least 49 mutations in the GAMT gene cause guanidinoacetate methyltransferase deficiency, a disorder that involves intellectual disability and seizures. Most affected individuals of Portuguese ancestry have a particular mutation in which the amino acid tryptophan is replaced by the amino acid serine at position 20 in the enzyme (written as Trp20Ser or W20S).

GAMT gene mutations impair the ability of the guanidinoacetate methyltransferase enzyme to participate in creatine synthesis, resulting in a shortage of creatine. The effects of guanidinoacetate methyltransferase deficiency are most severe in organs and tissues that require large amounts of energy, especially the brain.

Where is the GAMT gene located?

Cytogenetic Location: 19p13.3

Molecular Location on chromosome 19: base pairs 1,397,026 to 1,401,570

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBIThis link leads to a site outside Genetics Home Reference.)

The GAMT gene is located on the short (p) arm of chromosome 19 at position 13.3.

The GAMT gene is located on the short (p) arm of chromosome 19 at position 13.3.

More precisely, the GAMT gene is located from base pair 1,397,026 to base pair 1,401,570 on chromosome 19.

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

Where can I find additional information about GAMT?

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

  • PIG2
  • TP53I2

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 GAMT?

acids ; amino acid ; arginine ; compound ; contraction ; creatine ; deficiency ; disability ; enzyme ; expressed ; gene ; glucose ; glycine ; methionine ; methyltransferase ; mutation ; nervous system ; oxidation ; protein ; serine ; simple sugar ; stress ; synthesis ; tryptophan

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

See also Understanding Medical Terminology.

References (14 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: June 2015
Published: February 8, 2016