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GATM

glycine amidinotransferase

The *GATM* gene provides instructions for making the enzyme arginine:glycine amidinotransferase, which plays a critical role in the body's production of creatine. Creatine is essential for proper energy storage and utilisation within cells.

Chromosome 15q21.1 Polygenic HGNC:4175 Tier C
GATM 15q21.1 p arm q arm 15

GATM is located on the long (q) arm of chromosome 15, at band 15q21.1. Arm ratio per GRCh38 - banding schematic.

Explore chromosome 15 in the library →

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Clinical tests that include this

Carrier Screening panel
GATM is 1 of 1,008 genes on this panel
Expanded carrier screening for recessive and X-linked conditions
Newborn Genetic Screening panel
GATM is 1 of 258 genes on this panel
Genomic newborn screening for actionable paediatric conditions

Overview

The *GATM* gene, also known as glycine amidinotransferase, is vital for a fundamental biochemical process: the synthesis of creatine. Creatine is a compound stored primarily in muscle and brain tissue, where it acts as a rapidly accessible energy reserve. The enzyme produced from the *GATM* gene initiates the two-step pathway that converts amino acids into creatine, highlighting its importance for cellular energy dynamics.

What the gene does

The *GATM* gene codes for the enzyme arginine:glycine amidinotransferase. This enzyme is responsible for the first stage of creatine synthesis within the body. Specifically, it facilitates the transfer of a guanidino group from arginine to glycine, producing guanidinoacetic acid. This reaction is an essential biochemical step, as guanidinoacetic acid is subsequently converted into creatine in the second step of the pathway. Creatine itself is indispensable for the storage and efficient use of energy throughout the body, particularly in high-energy-demand tissues like muscles and the brain. Therefore, the function of the *GATM* enzyme is central to maintaining cellular energy homeostasis.

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Chromosome location

The *GATM* gene is located on chromosome 15, specifically at position 15q21.1. This genomic location refers to the long (q) arm of chromosome 15, within region 21, band 1.

Protein structure

Domain architecture has not been experimentally characterised in detail for this protein.

Key variants

Variants within the *GATM* gene can influence the activity of the arginine:glycine amidinotransferase enzyme. These genetic changes may affect the enzyme's structure, stability, or its ability to catalyse the initial step of creatine synthesis. The consequences of such variants can range from reduced enzyme function to complete loss of its activity, impacting the body's overall creatine production.

The table below shows the top 10 pathogenic or likely-pathogenic variants currently classified in ClinVar for GATM.
View all on ClinVar →

Sample of pathogenic variants

10 pathogenic / likely-pathogenic variants from ClinVar, ranked by review status (expert-panel-reviewed first). This is a sample; recurrent founder variants in a specific population may not appear here - see the full ClinVar listing via the link above.

Variant (HGVS) Protein change Classification Evidence Associated condition
c.1111dup
Duplication
 p.Met371fs Pathogenic ★★★☆ Arginine:glycine amidinotransferase deficiency
c.446G>A
single nucleotide variant
 p.Trp149Ter Pathogenic ★★★☆ Arginine:glycine amidinotransferase deficiency
c.484+1G>T
single nucleotide variant
 - Pathogenic ★★★☆ Arginine:glycine amidinotransferase deficiency
c.505C>T
single nucleotide variant
 p.Arg169Ter Pathogenic ★★★☆ Arginine:glycine amidinotransferase deficiency
c.629G>A
single nucleotide variant
 p.Trp210Ter Pathogenic ★★★☆ Arginine:glycine amidinotransferase deficiency
c.580C>T
single nucleotide variant
 p.Arg194Ter Pathogenic/Likely pathogenic ★★☆☆ Arginine:glycine amidinotransferase deficiency
g.(?_45661504)_(45670651_?)del
Deletion
 - Pathogenic ★☆☆☆ Arginine:glycine amidinotransferase deficiency
c.141dup
Duplication
 p.Asn48fs Pathogenic ★☆☆☆ Arginine:glycine amidinotransferase deficiency
c.92G>A
single nucleotide variant
 p.Trp31Ter Pathogenic ★☆☆☆ Arginine:glycine amidinotransferase deficiency
c.964C>T
single nucleotide variant
 p.Arg322Ter Pathogenic ★☆☆☆ Arginine:glycine amidinotransferase deficiency

Evidence stars indicate ClinVar review status. Individual variant interpretation should always be performed by a qualified clinical laboratory - many variants remain classified as Variants of Uncertain Significance (VUS) pending more research.

Associated conditions

Pathogenic variants in the *GATM* gene are associated with conditions that disrupt creatine metabolism. One such condition is Cerebral creatine deficiency, specifically arginine:glycine amidinotransferase deficiency (AGAT). This inherited disorder can lead to developmental delays, intellectual disability, and in some instances, muscle weakness, due to insufficient creatine production.

UK clinical status

The *GATM* gene is included in several UK NHS national genomic testing panels, indicating its clinical relevance in the UK. It is listed as 'green' on the DDG2P panel, the Intellectual disability panel, and the Undiagnosed metabolic disorders panel. Furthermore, it appears on the Likely inborn error of metabolism panel (R98), the Renal tubulopathies panel (R198), and the Tubulointerstitial kidney disease panel (R202), reflecting its role in a range of inherited conditions affecting metabolism and kidney function.

Green-listed
High evidence · clinically actionable in NHS testing
Included in NHS GMS signed-off panels
Likely inborn error of metabolism · R98 NHS GMS → Renal tubulopathies · R198 NHS GMS → Tubulointerstitial kidney disease · R202 NHS GMS → DDG2P NHS GMS → Intellectual disability NHS GMS →
NHS Genomic Medicine Service Jeen carrier screening

Sources: NHS GMS PanelApp · Genomics England PanelApp · NHS National Genomic Test Directory

Frequently asked questions

What is the primary function of the GATM gene?

The *GATM* gene provides instructions for creating the enzyme arginine:glycine amidinotransferase, which performs the first crucial step in the body's synthesis of creatine, a compound vital for energy storage.

What happens if the GATM gene is not working correctly?

If the *GATM* gene is not functioning properly, it can lead to a deficiency in creatine production. This can result in conditions such as arginine:glycine amidinotransferase deficiency, which may cause developmental delays, intellectual disability, and muscle weakness.

Is GATM deficiency a genetic condition?

Yes, arginine:glycine amidinotransferase deficiency, associated with the *GATM* gene, is an inherited genetic condition. The associated condition, Cerebral creatine deficiency, typically follows an autosomal recessive pattern of inheritance.

References

  1. Braissant O, Henry H, Béard E. Creatine deficiency syndromes and the importance of creatine synthesis in the brain. Amino acids. 2011. PMID: 21390529
  2. Nasrallah F, Feki M, Kaabachi N. Creatine and creatine deficiency syndromes: biochemical and clinical aspects. Pediatric neurology. 2010. PMID: 20159424
  3. Béard E, Braissant O. Synthesis and transport of creatine in the CNS: importance for cerebral functions. Journal of neurochemistry. 2010. PMID: 20796169
  4. Morris SM Jr. Enzymes of arginine metabolism. The Journal of nutrition. 2004. PMID: 15465778
  5. Sykut-Cegielska J, Gradowska W, Mercimek-Mahmutoglu S. Biochemical and clinical characteristics of creatine deficiency syndromes. Acta biochimica Polonica. 2004. PMID: 15625559
  6. Schulze A. Creatine deficiency syndromes. Molecular and cellular biochemistry. 2003. PMID: 12701824
  7. Item CB, Stöckler-Ipsiroglu S, Stromberger C. Arginine:glycine amidinotransferase deficiency: the third inborn error of creatine metabolism in humans. American journal of human genetics. 2001. PMID: 11555793
Educational content. This page is not medical or genetic advice, is not individually reviewed by a clinician for each reader, and should not replace a consultation with a qualified healthcare professional or genetic counsellor. If you are considering genetic testing or acting on a test result, book a consultation.
Data sources Last updated 13 September 2026. Content compiled from HGNC · MedlinePlus Genetics · ClinGen · Genomics England PanelApp · NHS National Genomic Test Directory · ClinVar · UniProt · AlphaFold .