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


Reviewed November 2011

What is the official name of the CHAT gene?

The official name of this gene is “choline O-acetyltransferase.”

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

What is the normal function of the CHAT gene?

The CHAT gene provides instructions for making a protein called choline acetyltransferase. This protein is located at the ends of nerve cells in specialized areas called presynaptic terminals. Choline acetyltransferase facilitates the production of a molecule called acetylcholine. Acetylcholine is essential for normal muscle movement. When acetylcholine is released from the presynaptic terminal, it attaches (binds) to a receptor protein located in the membrane of muscle cells. When acetylcholine binds to its receptor protein, specialized channels in the receptor then open, allowing certain charged atoms (ions) to flow into and out of muscle cells. The flow of these ions allows for muscle contraction and relaxation, resulting in muscle movement.

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

congenital myasthenic syndrome - caused by mutations in the CHAT gene

More than 30 mutations in the CHAT gene have been found to cause congenital myasthenic syndrome. Most of these mutations replace single DNA building blocks (nucleotides) in the CHAT gene. The mutations lead to decreased production of choline acetyltransferase or the production of a protein with decreased ability to aid in the production of acetylcholine. The resulting lack of acetylcholine decreases the availability of open receptors, impairing ion flow through muscle cells. A reduction in muscle cell ion flow decreases muscle movement leading to muscle weakness characteristic of congenital myasthenic syndrome. In addition, people with congenital myasthenic syndrome who have mutations in the CHAT gene are more likely than affected individuals with mutations in other genes to have short pauses in breathing (apnea), but the cause for this association is unclear.

Where is the CHAT gene located?

Cytogenetic Location: 10q11.2

Molecular Location on chromosome 10: base pairs 49,609,095 to 49,665,104

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

The CHAT gene is located on the long (q) arm of chromosome 10 at position 11.2.

The CHAT gene is located on the long (q) arm of chromosome 10 at position 11.2.

More precisely, the CHAT gene is located from base pair 49,609,095 to base pair 49,665,104 on chromosome 10.

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

Where can I find additional information about CHAT?

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

  • acetyl CoA:choline O-acetyltransferase
  • choline acetylase
  • CMS1A

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

What glossary definitions help with understanding CHAT?

acetylcholine ; apnea ; cell ; CoA ; congenital ; contraction ; DNA ; gene ; ions ; molecule ; muscle cell ; muscle cells ; presynaptic ; protein ; receptor ; syndrome

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


  • Barišić N, Chaouch A, Müller JS, Lochmüller H. Genetic heterogeneity and pathophysiological mechanisms in congenital myasthenic syndromes. Eur J Paediatr Neurol. 2011 May;15(3):189-96. doi: 10.1016/j.ejpn.2011.03.006. Epub 2011 Apr 17. Review. (
  • Engel AG, Shen XM, Selcen D, Sine SM. What have we learned from the congenital myasthenic syndromes. J Mol Neurosci. 2010 Jan;40(1-2):143-53. doi: 10.1007/s12031-009-9229-0. Epub 2009 Aug 18. Review. (
  • NCBI Gene (
  • Schara U, Christen HJ, Durmus H, Hietala M, Krabetz K, Rodolico C, Schreiber G, Topaloglu H, Talim B, Voss W, Pihko H, Abicht A, Müller JS, Lochmüller H. Long-term follow-up in patients with congenital myasthenic syndrome due to CHAT mutations. Eur J Paediatr Neurol. 2010 Jul;14(4):326-33. doi: 10.1016/j.ejpn.2009.09.009. Epub 2009 Nov 8. (


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: November 2011
Published: February 8, 2016