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GTR Home > Conditions/Phenotypes > Severe X-linked myotubular myopathy

Severe X-linked myotubular myopathy

Synonyms
MYOTUBULAR MYOPATHY 1; Myotubular myopathy, X-linked; X-linked centronuclear myopathy
Modes of inheritance
X-linked recessive inheritance (Orphanet)

Summary

Excerpted from the GeneReview: X-Linked Myotubular Myopathy
X-linked myotubular myopathy (X-MTM), also known as myotubular myopathy (MTM), is characterized by muscle weakness that ranges from severe to mild. Approximately 80% of affected males present with severe (classic) X-MTM characterized by polyhydramnios, decreased fetal movement, and neonatal weakness, hypotonia, and respiratory failure. Motor milestones are significantly delayed and most individuals fail to achieve independent ambulation. Weakness is profound and often involves facial and extraocular muscles. Respiratory failure is nearly uniform, with most individuals requiring 24-hour ventilatory assistance. It is estimated that at least 25% of boys with severe X-MTM die in the first year of life, and those who survive rarely live into adulthood. Males with mild or moderate X-MTM (~20%) achieve motor milestones more quickly than males with the severe form; many ambulate independently, and may live into adulthood. Most require gastrostomy tubes and/or ventilator support. In all subtypes of X-MTM, the muscle disease is not obviously progressive. Female carriers of X-MTM are generally asymptomatic, although manifesting heterozygotes are increasingly being identified. In affected females, symptoms range from severe, generalized weakness presenting in childhood, with infantile onset similar to affected male patients, to mild (often asymmetric) weakness manifesting in adulthood. Affected adult females may experience progressive respiratory decline and ultimately require ventilatory support.
Full text of GeneReview (by section):
Summary
Diagnosis
Clinical Characteristics
Genetically Related (Allelic) Disorders
Differential Diagnosis
Management
Genetic Counseling
Resources
Molecular Genetics
References
Chapter Notes
Authors:
James J Dowling
Michael W Lawlor
Soma Das
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Available tests

66 tests are in the database for this condition.

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Clinical tests (64 available)

Biochemical Genetics Tests

Molecular Genetics Tests

Research tests

Genes See tests for all associated and related genes

  • Also known as: CNM, CNMX, MTMX, XLMTM, MTM1
    Summary: myotubularin 1

Clinical features

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Imported from Human Phenotype Ontology (HPO)

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Reviews

Suggested reading

  • Frase, 2016
    Dream On: The Pursuit to Cure Myotubular Myopathy Born out of a Mother's Vision

Clinical resources

Practice guidelines

  • EuroGenetest, 2012
    Clinical utility gene card for: Centronuclear and myotubular myopathies.

Molecular resources

Consumer resources

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