X-Linked Myotubular Myopathy

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report X-Linked Myotubular Myopathy is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • MTM
  • myotubular myopathy
  • x-linked centronuclear myopathy

Disorder Subdivisions

  • None

General Discussion


X-linked myotubular myopathy (XLMTM) is a rare genetic neuromuscular disorder that is characterized by muscle weakness that can range from mild to profound. Symptoms are often present at birth, but may first develop during infancy or early childhood. In rare cases, symptoms may not develop until later, even adulthood. Common symptoms include mild to profound muscle weakness, diminished muscle tone (hypotonia or "floppiness"), feeding difficulties, and potentially severe breathing complications (respiratory distress). Feeding difficulties and respiratory distress develop because of weakness of the muscles that are involved in swallowing and breathing. The overall severity of the disorder can range from mildly affected individuals to individuals who develop severe, life-threatening complications during infancy and early childhood. Most affected individuals have a severe form of the disorder and respiratory failure is an almost uniform occurrence. XLMTM is caused by mutations to the myotubularin (MTM1) gene. The disorder is inherited as an X-linked recessive condition. The disorder predominantly affects males, but female carriers can develop mild symptoms. In rare specific cases, females can develop a severe form similar to that seen in males.


XLMTM belongs to a larger group of disorders known as the centronuclear myopathies. In addition to XLMTM, there are forms of centronuclear myopathy that are inherited as autosomal dominant or autosomal recessive conditions. Generally, the autosomal forms are less severe than XLMTM, however, in rare cases, individuals with an autosomal form can develop severe complications that are similar to those seen in XLMTM. Centronuclear myopathies derive their name from the abnormal location of the nucleus in the center of the muscle fiber (muscle cell) rather than its normal position on the edge. Additional pathologic features include disorganized perinuclear organelles and abnormalities in oxidative staining patterns. Centronuclear myopathies can be further classified into the larger, broader category of congenital myopathy, a group of genetic muscle disorders that are present at birth.

In the medical literature, centronuclear myopathy is generally used for the autosomal forms of the disorder and myotubular myopathy is generally used for the X-linked form. Distinguishing between the X-linked (myotubular) form and the autosomal forms is essential as the symptoms are usually more severe in the X-linked form. NORD has a separate report on centronuclear myopathy that describes the autosomal forms in greater detail. This report specifically deals with X-linked centronuclear (myotubular) myopathy.

Supporting Organizations

CLIMB (Children Living with Inherited Metabolic Diseases)

Climb Building
176 Nantwich Road
Crewe, CW2 6BG
United Kingdom
Tel: 4408452412173
Fax: 4408452412174
Email: enquiries@climb.org.uk
Website: http://www.CLIMB.org.uk

Contact A Family

209-211 City Road
London, EC1V 1JN
United Kingdom
Tel: 2076088700
Fax: 2076088701
Tel: 8088083555
Email: info@cafamily.org.uk
Website: http://www.cafamily.org.uk/

Cure CMD (Congenital Muscular Dystrophy)

P.O. Box 701
Olathe, KS 66051
Tel: (866)400-3626
Email: info@curecmd.com
Website: http://www.curecmd.org

European Alliance of Neuromuscular Disorders Associations

MDG Malta 4
Gzira Road
Gzira, GAR 04
Tel: 35621346688
Fax: 35621318024
Email: eamda@hotmail.com
Website: http://www.eamda.eu/

Genetic and Rare Diseases (GARD) Information Center

PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311
Website: http://rarediseases.info.nih.gov/GARD/

Joshua Frase Foundation

P.O. Box 2041
Ponte Vedra Beach, FL 32004
Tel: 904-607-1358
Fax: 904-273-9818
Email: info@joshuafrase.org
Website: http://www.joshuafrase.org/

Muscular Dystrophy Association

3300 East Sunrise Drive
Tucson, AZ 85718-3208
Tel: (520)529-2000
Fax: (520)529-5300
Tel: (800)572-1717
Email: mda@mdausa.org
Website: http://www.mda.org/

Muscular Dystrophy Campaign

61 Southwark Street
London, SE1 0HL
United Kingdom
Tel: 2078034800
Email: info@muscular-dystrophy.org
Website: http://www.muscular-dystrophy.org

Myotubular Myopathy Resource Group

2602 Quaker Drive
Texas City, TX 77590
Tel: (409)945-8569
Email: info@mtmrg.org
Website: http://www.mtmrg.org

Myotubular Trust

15a Barnard Road
London SW11 1QT
Tel: 07518 113692
Email: contact@myotubulartrust.org
Website: http://www.myotubulartrust.org

NIH/National Institute of Neurological Disorders and Stroke

P.O. Box 5801
Bethesda, MD 20824
Tel: (301)496-5751
Fax: (301)402-2186
Tel: (800)352-9424
Website: http://www.ninds.nih.gov/

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to www.rarediseases.org and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site www.rarediseases.org or email orphan@rarediseases.org

Last Updated:  12/30/1969
Copyright  2013 National Organization for Rare Disorders, Inc.