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Genetics Home Reference: your guide to understanding genetic conditions
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X-linked myotubular myopathy

Reviewed September 2008

What is X-linked myotubular myopathy?

X-linked myotubular myopathy is a condition that primarily affects muscles used for movement (skeletal muscles) and occurs almost exclusively in males.

People with this condition have muscle weakness (myopathy) and decreased muscle tone (hypotonia) that are usually evident at birth. These muscle problems impair the development of motor skills such as sitting, standing, and walking. Affected infants may also have difficulties with feeding due to muscle weakness. Individuals with X-linked myotubular myopathy frequently do not have the muscle strength to breathe unassisted and must be supported with a machine to help them breathe (mechanical ventilation). Some individuals need breathing assistance only periodically, typically during sleep, while others require it continuously. Affected individuals may also have weakness in the muscles that control eye movement (ophthalmoplegia), weakness in other muscles of the face, absent reflexes (areflexia), an abnormal curvature of the spine (scoliosis), joint deformities (contractures) of the hips and knees, and a large head with a narrow and elongated face.

Because of their severe breathing problems, individuals with X-linked myotubular myopathy usually survive only into early childhood; however, some people with this condition have lived into adulthood.

X-linked myotubular myopathy is a member of a group of disorders called centronuclear myopathies. In centronuclear myopathies, the nucleus is found at the center of many rod-shaped muscle cells instead of at either end, where it is normally located.

How common is X-linked myotubular myopathy?

The incidence of X-linked myotubular myopathy is estimated to be 1 in 50,000 newborn males worldwide.

What genes are related to X-linked myotubular myopathy?

Mutations in the MTM1 gene cause X-linked myotubular myopathy. 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.

MTM1 gene mutations probably disrupt myotubularin's role in muscle cell development and maintenance, causing muscle weakness and other signs and symptoms of X-linked myotubular myopathy.

Related Gene(s)

Changes in this gene are associated with X-linked myotubular myopathy.

  • MTM1

How do people inherit X-linked myotubular myopathy?

This condition is inherited in an X-linked recessive pattern. The gene associated with this condition is located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation must be present in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this gene, males are affected by X-linked recessive disorders much more frequently than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.

In X-linked recessive inheritance, a female with one altered copy of the gene in each cell is called a carrier. She can pass on the gene, but generally does not experience signs and symptoms of the disorder. In rare cases, however, carrier females have experienced some muscle weakness associated with X-linked myotubular myopathy.

Where can I find information about diagnosis or management of X-linked myotubular myopathy?

These resources address the diagnosis or management of X-linked myotubular myopathy and may include treatment providers.

  • Gene Review: X-Linked Centronuclear Myopathy (http://www.ncbi.nlm.nih.gov/books/NBK1432/)
  • Genetic Testing Registry: Severe x-linked myotubular myopathy (http://www.ncbi.nlm.nih.gov/gtr/conditions/C0410203)

You might also find information on the diagnosis or management of X-linked myotubular myopathy in Educational resources (http://www.ghr.nlm.nih.gov/condition/x-linked-myotubular-myopathy/show/Educational+resources) and Patient support (http://www.ghr.nlm.nih.gov/condition/x-linked-myotubular-myopathy/show/Patient+support).

General information about the diagnosis (http://ghr.nlm.nih.gov/handbook/consult/diagnosis) and management (http://ghr.nlm.nih.gov/handbook/consult/treatment) of genetic conditions is available in the Handbook. Read more about genetic testing (http://ghr.nlm.nih.gov/handbook/testing), particularly the difference between clinical tests and research tests (http://ghr.nlm.nih.gov/handbook/testing/researchtesting).

To locate a healthcare provider, see How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

Where can I find additional information about X-linked myotubular myopathy?

You may find the following resources about X-linked myotubular myopathy helpful. These materials are written for the general public.

  • MedlinePlus - Health information
    Health Topic: Muscle Disorders (http://www.nlm.nih.gov/medlineplus/muscledisorders.html)

  • Educational resources - Information pages

    • Children's Hospital Boston: Beggs Lab--Myotubular Myopathy (http://www.childrenshospital.org/cfapps/research/data_admin/Site1694/mainpageS1694P53.html)
    • Madisons Foundation (http://www.madisonsfoundation.org/index.php?option=com_mpower&task=disease&diseaseID=634)
    • Mayo Clinic: Congenital Myopathies (http://www.mayoclinic.org/congenital-myopathies/)
    • Orphanet (http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=EN&Expert=596)
    • Washington Univeristy, St. Louis: Neuromuscular Disease Center (http://neuromuscular.wustl.edu/syncm.html)

  • Patient support - For patients and families

    • CLIMB: Children Living with Inherited Metabolic Diseases (http://www.climb.org.uk/)
    • Family Village (http://www.familyvillage.wisc.edu/lib_myot.htm)
    • Joshua Frase Foundation (http://www.joshuafrase.org/about/congenital-myopathies.php)
    • Muscular Dystrophy Association (http://mda.org/disease/inherited-and-endocrine-myopathies/centronuclear-myotubular)
    • Muscular Dystrophy Campaign (http://www.muscular-dystrophy.org/about_muscular_dystrophy/conditions/114_myotubular_centronuclear_myopathy)
    • Myotubular Trust (http://www.myotubulartrust.com/index.htm)
    • National Organization for Rare Disorders (NORD) (http://www.rarediseases.org/rare-disease-information/rare-diseases/byID/983/viewAbstract)
    • University of Kansas Medical Center Resource List (http://www.kumc.edu/gec/support/muscular.html)

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

  • Gene Reviews - Clinical summary (http://www.ncbi.nlm.nih.gov/books/NBK1432/)

  • Genetic Testing Registry - Repository of genetic test information

    • Genetic Testing Registry: Severe x-linked myotubular myopathy (http://www.ncbi.nlm.nih.gov/gtr/conditions/C0410203)
  • ClinicalTrials.gov - Linking patients to medical research (http://clinicaltrials.gov/ct2/results?cond=%22X-linked%20myotubular%20myopathy%22)
  • PubMed - Recent literature (http://www.ncbi.nlm.nih.gov/pubmed?term=((x-linked%20myotubular%20myopathy%5BTIAB%5D)%20OR%20(x-linked%20centronuclear%20myopathy%5BTIAB%5D))%20AND%20english%5Bla%5D%20AND%20human%5Bmh%5D%20AND%20%22last%201800%20days%22%5Bdp%5D)
  • OMIM - Genetic disorder catalog (http://omim.org/entry/310400)

What other names do people use for X-linked myotubular myopathy?

  • CNM
  • MTMX
  • X-linked centronuclear myopathy
  • XLMTM
  • XMTM

For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines (http://ghr.nlm.nih.gov/ConditionNameGuide) and How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What if I still have specific questions about X-linked myotubular myopathy?

Ask the Genetic and Rare Diseases Information Center (http://rarediseases.info.nih.gov/GARD/).

What glossary definitions help with understanding X-linked myotubular myopathy?

carrier ; cell ; chromosome ; decreased muscle tone ; enzyme ; gene ; hypotonia ; incidence ; inheritance ; joint ; motor ; muscle tone ; mutation ; nucleus ; ophthalmoplegia ; recessive ; scoliosis ; sex chromosomes ; X-linked recessive

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).

References

  • 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. (http://www.ncbi.nlm.nih.gov/pubmed/12522554?dopt=Abstract)
  • Bijarnia S, Puri RD, Jain M, Kler N, Roy S, Urtizberea JA, Biancalana V, Verma IC. Mutation studies in X-linked myotubular myopathy in three Indian families. Indian J Pediatr. 2010 Apr;77(4):431-3. doi: 10.1007/s12098-010-0057-6. Epub 2010 Mar 31. (http://www.ncbi.nlm.nih.gov/pubmed/20358311?dopt=Abstract)
  • Cahill PJ, Rinella AS, Bielski RJ. Orthopaedic complications of myotubular myopathy. J Pediatr Orthop. 2007 Jan-Feb;27(1):98-103. (http://www.ncbi.nlm.nih.gov/pubmed/17195806?dopt=Abstract)
  • Gene Review: X-Linked Centronuclear Myopathy (http://www.ncbi.nlm.nih.gov/books/NBK1432/)
  • Hoffjan S, Thiels C, Vorgerd M, Neuen-Jacob E, Epplen JT, Kress W. Extreme phenotypic variability in a German family with X-linked myotubular myopathy associated with E404K mutation in MTM1. Neuromuscul Disord. 2006 Nov;16(11):749-53. Epub 2006 Sep 26. (http://www.ncbi.nlm.nih.gov/pubmed/17005396?dopt=Abstract)
  • Lawlor MW, Alexander MS, Viola MG, Meng H, Joubert R, Gupta V, Motohashi N, Manfready RA, Hsu CP, Huang P, Buj-Bello A, Kunkel LM, Beggs AH, Gussoni E. Myotubularin-deficient myoblasts display increased apoptosis, delayed proliferation, and poor cell engraftment. Am J Pathol. 2012 Sep;181(3):961-8. doi: 10.1016/j.ajpath.2012.05.016. Epub 2012 Jul 27. (http://www.ncbi.nlm.nih.gov/pubmed/22841819?dopt=Abstract)
  • 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. (http://www.ncbi.nlm.nih.gov/pubmed/12467749?dopt=Abstract)
  • Pierson CR, Tomczak K, Agrawal P, Moghadaszadeh B, Beggs AH. X-linked myotubular and centronuclear myopathies. J Neuropathol Exp Neurol. 2005 Jul;64(7):555-64. Review. (http://www.ncbi.nlm.nih.gov/pubmed/16042307?dopt=Abstract)

 

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? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: September 2008
Published: May 20, 2013