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MTM1 gene

myotubularin 1

Normal Function

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.

Health Conditions Related to Genetic Changes

X-linked myotubular myopathy

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.

More About This Health Condition

Other Names for This Gene

  • CNM
  • MTMX
  • myotubularin

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases


  • Begley MJ, Dixon JE. The structure and regulation of myotubularin phosphatases. Curr Opin Struct Biol. 2005 Dec;15(6):614-20. doi: 10.1016/ Epub 2005 Nov 9. Citation on PubMed
  • 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. doi: 10.1007/s00439-002-0869-1. Epub 2002 Nov 28. Citation on PubMed
  • 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. doi: 10.1016/s0960-8966(02)00153-0. Citation on PubMed
  • Robinson FL, Dixon JE. Myotubularin phosphatases: policing 3-phosphoinositides. Trends Cell Biol. 2006 Aug;16(8):403-12. doi: 10.1016/j.tcb.2006.06.001. Epub 2006 Jul 7. Citation on PubMed
  • Tronchere 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. doi: 10.1074/jbc.M311071200. Epub 2003 Dec 1. Citation on PubMed

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.