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


Reviewed September 2008

What is the official name of the MTM1 gene?

The official name of this gene is “myotubularin 1.”

MTM1 is the gene's official symbol. The MTM1 gene is also known by other names, listed below.

What is the normal function of the MTM1 gene?

The MTM1 gene provides instructions for producing an enzyme called myotubularin. Myotubularin is thought to be involved in the development and maintenance of muscle cells. This enzyme acts as a phosphatase, which means that it removes clusters of oxygen and phosphorus atoms (phosphate groups) from other molecules. Myotubularin removes phosphate groups from two molecules called phosphatidylinositol 3-phosphate and phosphatidylinositol 3,5-biphosphate. These molecules are found within cell membranes and are likely involved in transporting molecules within cells.

Does the MTM1 gene share characteristics with other genes?

The MTM1 gene belongs to a family of genes called PTP (protein tyrosine phosphatases).

A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? ( in the Handbook.

How are changes in the MTM1 gene related to health conditions?

X-linked myotubular myopathy - caused by mutations in the MTM1 gene

More than 200 mutations in the MTM1 gene have been found to cause X-linked myotubular myopathy. Some MTM1 gene mutations change one of the protein building blocks (amino acids) in myotubularin, while other mutations result in an abnormally short, nonfunctional enzyme. The MTM1 gene mutations that prevent the production of any functional myotubularin tend to result in a more severe disease. Individuals who are mildly affected tend to have an MTM1 mutation that allows some functional myotubularin to be produced.

Mutations in the MTM1 gene are thought to disrupt myotubularin's role in muscle cell development and maintenance, causing muscle weakness and other signs and symptoms of X-linked myotubular myopathy.

Where is the MTM1 gene located?

Cytogenetic Location: Xq28

Molecular Location on the X chromosome: base pairs 150,562,658 to 150,673,143

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

The MTM1 gene is located on the long (q) arm of the X chromosome at position 28.

The MTM1 gene is located on the long (q) arm of the X chromosome at position 28.

More precisely, the MTM1 gene is located from base pair 150,562,658 to base pair 150,673,143 on the X chromosome.

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

Where can I find additional information about MTM1?

You and your healthcare professional may find the following resources about MTM1 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 MTM1 gene or gene products?

  • CNM
  • MTMX
  • myotubularin

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

What glossary definitions help with understanding MTM1?

acids ; cell ; enzyme ; gene ; muscle cell ; muscle cells ; mutation ; oxygen ; phosphatase ; phosphate ; phosphorus ; protein

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


  • Begley MJ, Dixon JE. The structure and regulation of myotubularin phosphatases. Curr Opin Struct Biol. 2005 Dec;15(6):614-20. Epub 2005 Nov 9. Review. (
  • Biancalana V, Caron O, Gallati S, Baas F, Kress W, Novelli G, D'Apice MR, Lagier-Tourenne C, Buj-Bello A, Romero NB, Mandel JL. Characterisation of mutations in 77 patients with X-linked myotubular myopathy, including a family with a very mild phenotype. Hum Genet. 2003 Feb;112(2):135-42. Epub 2002 Nov 28. (
  • McEntagart M, Parsons G, Buj-Bello A, Biancalana V, Fenton I, Little M, Krawczak M, Thomas N, Herman G, Clarke A, Wallgren-Pettersson C. Genotype-phenotype correlations in X-linked myotubular myopathy. Neuromuscul Disord. 2002 Dec;12(10):939-46. (
  • NCBI Gene (
  • Robinson FL, Dixon JE. Myotubularin phosphatases: policing 3-phosphoinositides. Trends Cell Biol. 2006 Aug;16(8):403-12. Epub 2006 Jul 7. Review. (
  • Tronchère H, Laporte J, Pendaries C, Chaussade C, Liaubet L, Pirola L, Mandel JL, Payrastre B. Production of phosphatidylinositol 5-phosphate by the phosphoinositide 3-phosphatase myotubularin in mammalian cells. J Biol Chem. 2004 Feb 20;279(8):7304-12. Epub 2003 Dec 1. (


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: September 2008
Published: February 1, 2016