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


Reviewed April 2007

What is the official name of the AMT gene?

The official name of this gene is “aminomethyltransferase.”

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

What is the normal function of the AMT gene?

The AMT gene provides instructions for making an enzyme called aminomethyltransferase. This enzyme is one of four components (subunits) that make up a large complex called glycine cleavage enzyme. Within cells, this complex is active in specialized energy-producing centers called mitochondria.

As its name suggests, glycine cleavage enzyme processes a molecule called glycine by cutting (cleaving) it into smaller pieces. Glycine is an amino acid, which is a building block of proteins. This molecule also acts as a neurotransmitter, which is a chemical messenger that transmits signals in the brain. The breakdown of excess glycine is necessary for the normal development and function of nerve cells in the brain and spinal cord.

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

glycine encephalopathy - caused by mutations in the AMT gene

Mutations in the AMT gene are responsible for 10 percent to 15 percent of all cases of glycine encephalopathy. More than a dozen mutations have been identified in affected individuals. Most of these genetic changes alter single amino acids in aminomethyltransferase. Other mutations delete genetic material from the AMT gene or disrupt how genetic information from the gene is spliced together to make a blueprint for producing aminomethyltransferase.

AMT mutations alter the structure and function of aminomethyltransferase. When an altered version of this enzyme is incorporated into the glycine cleavage enzyme complex, it prevents the complex from breaking down glycine properly. As a result, excess glycine can build up to toxic levels in the body's organs and tissues. Damage caused by harmful amounts of this molecule in the brain and spinal cord is responsible for the intellectual disability, seizures, and breathing difficulties characteristic of glycine encephalopathy.

Where is the AMT gene located?

Cytogenetic Location: 3p21.31

Molecular Location on chromosome 3: base pairs 49,416,778 to 49,422,678

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

The AMT gene is located on the short (p) arm of chromosome 3 at position 21.31.

The AMT gene is located on the short (p) arm of chromosome 3 at position 21.31.

More precisely, the AMT gene is located from base pair 49,416,778 to base pair 49,422,678 on chromosome 3.

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

Where can I find additional information about AMT?

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

  • GCE
  • GCST
  • GCVT
  • glycine cleavage system protein T
  • Glycine Decarboxylase Complex T-Protein
  • NKH

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

What glossary definitions help with understanding AMT?

acids ; amino acid ; breakdown ; disability ; encephalopathy ; enzyme ; gene ; glycine ; mitochondria ; molecule ; protein ; toxic

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


  • Gene Review: Glycine Encephalopathy (
  • Kure S, Kato K, Dinopoulos A, Gail C, DeGrauw TJ, Christodoulou J, Bzduch V, Kalmanchey R, Fekete G, Trojovsky A, Plecko B, Breningstall G, Tohyama J, Aoki Y, Matsubara Y. Comprehensive mutation analysis of GLDC, AMT, and GCSH in nonketotic hyperglycinemia. Hum Mutat. 2006 Apr;27(4):343-52. (
  • NCBI Gene (
  • Okamura-Ikeda K, Hosaka H, Yoshimura M, Yamashita E, Toma S, Nakagawa A, Fujiwara K, Motokawa Y, Taniguchi H. Crystal structure of human T-protein of glycine cleavage system at 2.0 A resolution and its implication for understanding non-ketotic hyperglycinemia. J Mol Biol. 2005 Sep 2;351(5):1146-59. (
  • Toone JR, Applegarth DA, Levy HL, Coulter-Mackie MB, Lee G. Molecular genetic and potential biochemical characteristics of patients with T-protein deficiency as a cause of glycine encephalopathy (NKH). Mol Genet Metab. 2003 Aug;79(4):272-80. (


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: April 2007
Published: February 8, 2016