Submitted Successfully!
To reward your contribution, here is a gift for you: A free trial for our video production service.
Thank you for your contribution! You can also upload a video entry or images related to this topic.
Version Summary Created by Modification Content Size Created at Operation
1 + 351 word(s) 351 2020-12-15 07:26:02

Video Upload Options

Do you have a full video?


Are you sure to Delete?
If you have any further questions, please contact Encyclopedia Editorial Office.
Xu, C. Guanidinoacetate Methyltransferase Deficiency. Encyclopedia. Available online: (accessed on 20 June 2024).
Xu C. Guanidinoacetate Methyltransferase Deficiency. Encyclopedia. Available at: Accessed June 20, 2024.
Xu, Camila. "Guanidinoacetate Methyltransferase Deficiency" Encyclopedia, (accessed June 20, 2024).
Xu, C. (2020, December 23). Guanidinoacetate Methyltransferase Deficiency. In Encyclopedia.
Xu, Camila. "Guanidinoacetate Methyltransferase Deficiency." Encyclopedia. Web. 23 December, 2020.
Guanidinoacetate Methyltransferase Deficiency

Guanidinoacetate methyltransferase deficiency is an inherited disorder that primarily affects the brain and muscles.

genetic conditions

1. Introduction

Without early treatment, people with this disorder have neurological problems that are usually severe. These problems include intellectual disability, speech development limited to a few words, and recurrent seizures (epilepsy). Affected individuals may also exhibit autistic behaviors that affect communication and social interaction or self-injurious behaviors such as head-banging. Other features of this disorder can include involuntary movements (extrapyramidal dysfunction) such as tremors or facial tics.

People with guanidinoacetate methyltransferase deficiency may have weak muscle tone and delayed development of motor skills such as sitting or walking. In severe cases they may lose previously acquired skills such as the ability to support their head or to sit unsupported.

2. Frequency

Guanidinoacetate methyltransferase deficiency is a very rare disorder. About 80 affected individuals have been described in the medical literature. Of these, approximately one-third are of Portuguese origin.

3. Causes

Mutations in the GAMT gene cause guanidinoacetate methyltransferase deficiency. The GAMT gene provides instructions for making the enzyme guanidinoacetate methyltransferase. 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.

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.

4. Inheritance

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

5. Other Names for This Condition

  • creatine deficiency syndrome due to GAMT deficiency

  • deficiency of guanidinoacetate methyltransferase

  • GAMT deficiency


  1. Almeida LS, Vilarinho L, Darmin PS, Rosenberg EH, Martinez-Muñoz C, Jakobs C, Salomons GS. A prevalent pathogenic GAMT mutation (c.59G>C) in Portugal. MolGenet Metab. 2007 May;91(1):1-6.
  2. Braissant O, Henry H, Béard E, Uldry J. Creatine deficiency syndromes and the importance of creatine synthesis in the brain. Amino Acids. 2011May;40(5):1315-24. doi: 10.1007/s00726-011-0852-z.
  3. Braissant O. GAMT deficiency: 20 years of a treatable inborn error ofmetabolism. Mol Genet Metab. 2014 Jan;111(1):1-3. doi:10.1016/j.ymgme.2013.11.002.
  4. Béard E, Braissant O. Synthesis and transport of creatine in the CNS:importance for cerebral functions. J Neurochem. 2010 Oct;115(2):297-313. doi:10.1111/j.1471-4159.2010.06935.x.
  5. Dhar SU, Scaglia F, Li FY, Smith L, Barshop BA, Eng CM, Haas RH, Hunter JV,Lotze T, Maranda B, Willis M, Abdenur JE, Chen E, O'Brien W, Wong LJ. Expandedclinical and molecular spectrum of guanidinoacetate methyltransferase (GAMT)deficiency. Mol Genet Metab. 2009 Jan;96(1):38-43. doi:10.1016/j.ymgme.2008.10.008.
  6. El-Gharbawy AH, Goldstein JL, Millington DS, Vaisnins AE, Schlune A, BarshopBA, Schulze A, Koeberl DD, Young SP. Elevation of guanidinoacetate in newborndried blood spots and impact of early treatment in GAMT deficiency. Mol GenetMetab. 2013 Jun;109(2):215-7. doi: 10.1016/j.ymgme.2013.03.003.
  7. Gordon N. Guanidinoacetate methyltransferase deficiency (GAMT). Brain Dev.2010 Feb;32(2):79-81. doi: 10.1016/j.braindev.2009.01.008.Review.
  8. Mercimek-Mahmutoglu S, Ndika J, Kanhai W, de Villemeur TB, Cheillan D,Christensen E, Dorison N, Hannig V, Hendriks Y, Hofstede FC, Lion-Francois L,Lund AM, Mundy H, Pitelet G, Raspall-Chaure M, Scott-Schwoerer JA, Szakszon K,Valayannopoulos V, Williams M, Salomons GS. Thirteen new patients withguanidinoacetate methyltransferase deficiency and functional characterization of nineteen novel missense variants in the GAMT gene. Hum Mutat. 2014Apr;35(4):462-9. doi: 10.1002/humu.22511.
  9. Mercimek-Mahmutoglu S, Sinclair G, van Dooren SJ, Kanhai W, Ashcraft P, MichelOJ, Nelson J, Betsalel OT, Sweetman L, Jakobs C, Salomons GS. Guanidinoacetatemethyltransferase deficiency: first steps to newborn screening for a treatableneurometabolic disease. Mol Genet Metab. 2012 Nov;107(3):433-7. doi:10.1016/j.ymgme.2012.07.022.
  10. Nasrallah F, Feki M, Kaabachi N. Creatine and creatine deficiency syndromes:biochemical and clinical aspects. Pediatr Neurol. 2010 Mar;42(3):163-71. doi:10.1016/j.pediatrneurol.2009.07.015. Review.
  11. Pasquali M, Schwarz E, Jensen M, Yuzyuk T, DeBiase I, Randall H, Longo N.Feasibility of newborn screening for guanidinoacetate methyltransferase (GAMT)deficiency. J Inherit Metab Dis. 2014 Mar;37(2):231-6. doi:10.1007/s10545-013-9662-7.
  12. Stockler-Ipsiroglu S, van Karnebeek C, Longo N, Korenke GC,Mercimek-Mahmutoglu S, Marquart I, Barshop B, Grolik C, Schlune A, Angle B,Araújo HC, Coskun T, Diogo L, Geraghty M, Haliloglu G, Konstantopoulou V, Leuzzi V, Levtova A, Mackenzie J, Maranda B, Mhanni AA, Mitchell G, Morris A, Newlove T,Renaud D, Scaglia F, Valayannopoulos V, van Spronsen FJ, Verbruggen KT, Yuskiv N,Nyhan W, Schulze A. Guanidinoacetate methyltransferase (GAMT) deficiency:outcomes in 48 individuals and recommendations for diagnosis, treatment andmonitoring. Mol Genet Metab. 2014 Jan;111(1):16-25. doi:10.1016/j.ymgme.2013.10.018.
  13. Stockler-Ipsiroglu S, van Karnebeek CD. Cerebral creatine deficiencies: agroup of treatable intellectual developmental disorders. Semin Neurol. 2014Jul;34(3):350-6. doi: 10.1055/ Semin Neurol. 2014 Sep;34(4):479.
  14. Viau KS, Ernst SL, Pasquali M, Botto LD, Hedlund G, Longo N. Evidence-basedtreatment of guanidinoacetate methyltransferase (GAMT) deficiency. Mol GenetMetab. 2013 Nov;110(3):255-62. doi: 10.1016/j.ymgme.2013.08.020.
Contributor MDPI registered users' name will be linked to their SciProfiles pages. To register with us, please refer to :
View Times: 302
Entry Collection: MedlinePlus
Revision: 1 time (View History)
Update Date: 23 Dec 2020
Video Production Service