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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 GNMT gene?

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

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

What is the normal function of the GNMT gene?

The GNMT gene provides instructions for producing the enzyme glycine N-methyltransferase. This enzyme is involved in a multistep process that breaks down the protein building block (amino acid) methionine. Specifically, glycine N-methyltransferase starts a reaction that converts the compounds glycine and S-adenosylmethionine (also called AdoMet) to N-methylglycine and S-adenosylhomocysteine (also called AdoHcy).

This reaction also helps to control the relative amounts of AdoMet and AdoHcy. The AdoMet to AdoHcy ratio is important in many body processes, including the regulation of other genes by the addition of methyl groups, consisting of one carbon atom and three hydrogen atoms (methylation). Methylation is important in many cellular functions. These include determining whether the instructions in a particular segment of DNA are carried out, regulating reactions involving proteins and lipids, and controlling the processing of chemicals that relay signals in the nervous system (neurotransmitters).

The glycine N-methyltransferase enzyme is also involved in processing toxic compounds in the liver.

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

hypermethioninemia - caused by mutations in the GNMT gene

Three mutations in the GNMT gene have been described in individuals with hypermethioninemia. In an Italian family, one mutation substitutes the amino acid proline for the amino acid leucine at protein position 49 (written as Leu49Pro or L49P) and another mutation substitutes the amino acid asparagine for the amino acid histidine at position 176 (written as His176Asn or H176N). In a Greek patient of Roma origin, a mutation was identified that substitutes the amino acid serine for the amino acid asparagine at position 140 (written as Asn140Ser or N140S). The reduced glycine N-methyltransferase activity resulting from these mutations causes hypermethioninemia in affected individuals.

cancers - increased risk from variations of the GNMT gene

Certain inherited variations in the GNMT gene have been associated with an increased risk of liver and prostate cancers. Other GNMT gene mutations that have been found in cancerous tumors are acquired during a person's lifetime and are present only in certain cells. These changes, which are called somatic mutations, are not inherited. GNMT gene mutations likely impair glycine N-methyltransferase functions such as processing potential cancer-causing substances in the liver and helping to regulate other genes, including those responsible for controlling cell growth. When cells grow too rapidly or in an uncontrolled way, a cancerous tumor can form.

Where is the GNMT gene located?

Cytogenetic Location: 6p12

Molecular Location on chromosome 6: base pairs 42,939,415 to 42,963,880

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

The GNMT gene is located on the short (p) arm of chromosome 6 at position 12.

The GNMT gene is located on the short (p) arm of chromosome 6 at position 12.

More precisely, the GNMT gene is located from base pair 42,939,415 to base pair 42,963,880 on chromosome 6.

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

Where can I find additional information about GNMT?

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

  • Glycine Methyltransferase
  • Glycine Sarcosine Methyltransferase
  • Glycine Sarcosine N-Methyltransferase

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

What glossary definitions help with understanding GNMT?

amino acid ; asparagine ; atom ; cancer ; cell ; DNA ; enzyme ; gene ; glycine ; histidine ; inherited ; leucine ; methionine ; methyl ; methylation ; methyltransferase ; mutation ; nervous system ; neurotransmitters ; proline ; prostate ; protein ; serine ; toxic ; tumor

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


  • Augoustides-Savvopoulou P, Luka Z, Karyda S, Stabler SP, Allen RH, Patsiaoura K, Wagner C, Mudd SH. Glycine N -methyltransferase deficiency: a new patient with a novel mutation. J Inherit Metab Dis. 2003;26(8):745-59. (
  • Bhat R, Bresnick E. Glycine N-methyltransferase is an example of functional diversity. Role as a polycyclic aromatic hydrocarbon-binding receptor. J Biol Chem. 1997 Aug 22;272(34):21221-6. (
  • Biochemistry (fifth edition, 2002): Methionine Metabolism (
  • Chen SY, Lin JR, Darbha R, Lin P, Liu TY, Chen YM. Glycine N-methyltransferase tumor susceptibility gene in the benzo(a)pyrene-detoxification pathway. Cancer Res. 2004 May 15;64(10):3617-23. (
  • Huang YC, Lee CM, Chen M, Chung MY, Chang YH, Huang WJ, Ho DM, Pan CC, Wu TT, Yang S, Lin MW, Hsieh JT, Chen YM. Haplotypes, loss of heterozygosity, and expression levels of glycine N-methyltransferase in prostate cancer. Clin Cancer Res. 2007 Mar 1;13(5):1412-20. (
  • Luka Z, Capdevila A, Mato JM, Wagner C. A glycine N-methyltransferase knockout mouse model for humans with deficiency of this enzyme. Transgenic Res. 2006 Jun;15(3):393-7. (
  • Luka Z, Cerone R, Phillips JA 3rd, Mudd HS, Wagner C. Mutations in human glycine N-methyltransferase give insights into its role in methionine metabolism. Hum Genet. 2002 Jan;110(1):68-74. Epub 2001 Dec 7. (
  • Luka Z, Wagner C. Effect of naturally occurring mutations in human glycine N-methyltransferase on activity and conformation. Biochem Biophys Res Commun. 2003 Dec 26;312(4):1067-72. (
  • Mudd SH, Cerone R, Schiaffino MC, Fantasia AR, Minniti G, Caruso U, Lorini R, Watkins D, Matiaszuk N, Rosenblatt DS, Schwahn B, Rozen R, LeGros L, Kotb M, Capdevila A, Luka Z, Finkelstein JD, Tangerman A, Stabler SP, Allen RH, Wagner C. Glycine N-methyltransferase deficiency: a novel inborn error causing persistent isolated hypermethioninaemia. J Inherit Metab Dis. 2001 Aug;24(4):448-64. (
  • NCBI Gene (
  • Ogawa H, Gomi T, Takusagawa F, Fujioka M. Structure, function and physiological role of glycine N-methyltransferase. Int J Biochem Cell Biol. 1998 Jan;30(1):13-26. Review. (
  • Smythies JR, Gottfries CG, Regland B. Disturbances of one-carbon metabolism in neuropsychiatric disorders: a review. Biol Psychiatry. 1997 Jan 15;41(2):230-3. Review. (
  • Tseng TL, Shih YP, Huang YC, Wang CK, Chen PH, Chang JG, Yeh KT, Chen YM, Buetow KH. Genotypic and phenotypic characterization of a putative tumor susceptibility gene, GNMT, in liver cancer. Cancer Res. 2003 Feb 1;63(3):647-54. (


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 1, 2016