Back to Gene
MTM1 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

MTM1 gene

The MTM1 gene provides instructions for producing the enzyme myotubularin, which is essential for the development and maintenance of muscle cells.

Normal Function

The MTM1 gene provides instructions for producing an enzyme called myotubularin. This enzyme acts as a phosphatase, meaning it removes phosphate groups from specific molecules (phosphatidylinositol 3-phosphate and phosphatidylinositol 3,5-biphosphate) found within cell membranes. These molecules are involved in transporting materials within cells, and myotubularin's activity is critical for the proper development and maintenance of muscle cells.

Health Conditions Related to Genetic Changes

X-linked myotubular myopathy

More than 200 mutations in the MTM1 gene have been identified as the cause of X-linked myotubular myopathy. These mutations can result in an abnormally short, nonfunctional enzyme or change specific amino acids within the protein.

  • Severe cases: Mutations that prevent the production of any functional myotubularin typically result in more severe disease.
  • Mild cases: Individuals who are mildly affected often have mutations that still allow for the production of some functional myotubularin.

These mutations disrupt the role of myotubularin in muscle cell development, leading to the muscle weakness and other symptoms characteristic of this condition.

Frequently Asked Questions

Newborns with severe X‑linked myotubular myopathy often show profound hypotonia (floppy baby), weak or absent reflexes, and difficulty breathing or feeding within the first few days of life. Mild cases may present later with muscle weakness, delayed motor milestones, or difficulty standing and walking.
Children with residual myotubularin activity often achieve independent ambulation, though they may experience chronic muscle weakness and fatigue. Regular monitoring for respiratory and cardiac complications is essential, and early intervention with physiotherapy can improve functional outcomes.
definitive diagnosis requires genetic testing of the MTM1 gene, usually through next‑generation sequencing or a targeted mutation panel. If a mutation is found, a muscle biopsy may be performed to assess myotubularin protein levels and confirm the functional impact.
Current management is largely supportive: respiratory support (ventilatory assistance or tracheostomy), physical therapy to maintain muscle tone, and cardiac monitoring. Experimental therapies, such as gene therapy trials using adeno‑associated viral vectors to deliver functional MTM1, are under investigation and may become available in specialized centers.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

Meyahealth

Ⓒ 2026. All rights reserved by MEYA