What is Myotubular Myopathy?

Myotubular myopathy is recognized as a severe type of centronuclear myopathy, which is viewed as a kind of inherited myopathy which causes issues with the contraction and tone of skeletal muscles. However, the severity of centronuclear myopathy differs among people, even among members belonging to the same family. It is important to know about the signs and symptoms, causes, diagnosis and treatment of myotubular myopathy.

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Individuals with centronuclear myopathy start undergoing muscle weakness at any time beginning from birth to a person’s early childhood. Again, the muscle weakness becomes worse with each passing day and it can result in a late motor skills development, like crawling, difficulty in walking and muscle pain at the time of exercising. Some patients also require the assistance of a wheelchair because the muscle weakness and atrophy turns severe. Sometimes, in some rare instances, the weakness of muscles improves over time.

Signs and Symptoms of Myotubular Myopathy

The main signs and symptoms of myotubular myopathy revolve around muscle health. Myotubular myopathy causes hypotonia and muscle weakness which become noticeable at birth. The hypotonia and weakness do interfere with movement and posture and it can result in life-threatening complexities with respiration and feeding. At times, infection or failure of the lungs can cause death in early infancy; however, some infants suffering from this disease stay alive. Generally, children suffering from this disease do need assisted ventilation and a feeding tube. Again, contractures might develop too especially in the knees and the hips. There also occurs a chance of spinal curvature in childhood.

Causes of Myotubular Myopathy

The causes of myotubular myopathy are related to the deficiencies and defects of myotubularin, which is a protein. Myotubularin is highly useful in endorsing normal muscle development. This disorder gets inherited through an X-linked recessive pattern, which means it commonly affects boys. They inherit this disease via their mothers. When girls get affected, then this condition becomes less severe compared to boys.

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Prevention of Myotubular Myopathy

There isn’t a known way to prevent myotubular myopathy. If there is a family history, then your child is at greater risk of having myotubular myopathy, it is advisable to consult a genetic counsellor before planning a baby. Here, a genetic counselor can aid you in understanding your chances of having a child suffering from this disorder. They can guide you with the prenatal examinations which are obtainable and assist the pros and cons of the examination.

Diagnosis of Myotubular Myopathy

Centronuclear myopathy ought to be suspected in the newborns with muscle weakness and hypotonia and older children with weakness in the legs and arms. A diagnosis of myotubular myopathy is made upon the recognition of extra characteristic symptoms, a comprehensive clinical evaluation, a detailed personal and family history, and various specialized examinations.

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A muscle biopsy might be performed for getting a diagnosis. A biopsy comprises of surgical removal of a little sample of the affected muscle tissue and microscopic testing of the sample. This permits doctors to notice the characteristic and microscopic alterations in muscle tissue.

A specialized imaging process, like a muscle MRI, might be used for identifying the choice of genetic testing in various forms of CNM, especially in RYR1 and DNM2-related CNM. An MRI makes use of a magnetic field for producing cross-sectional images of specific body and organ tissues, like skeletal muscle tissue.

The diagnosis of CNM can get confirmed via molecular genetic testing that can sense the characteristic gene mutation which causes particular forms of this disease.

Treatment for Myotubular Myopathy

The treatment of myotubular myopathy is directed towards particular signs which become obvious in each patient. Its treatment might need the coordinated efforts of specialists having expertise in treating neuromuscular problems.

Pulmonologists, pediatricians, orthopedists, neurologists, dental specialists, eye specialists, and various healthcare professionals might be required to comprehensively and systematically treat the affected patient.

Genetic counseling turns highly beneficial for affected patients and their families. Some people might not need ventilation assistance, whereas some people might only require ventilation-assistance for a particular period of time.

People suffering from serious forms of CNM will need constant and prolonged ventilation support. There are various mechanisms of ventilation that comprise non-invasive and invasive processes. The decision regarding the kind of ventilation as well as the duration of respiratory support can be made by the family based on the guidance given by the team of healthcare providers managing the case.

Some people having problems with feeding will need inserting a feeding tube. This process comprises inserting a tube into the stomach directly via a little surgical opening in the patient’s abdominal wall. Occupational and physical therapy too is recommended for improving muscle strength and preventing contractures. At times, special measures are needed for permitting ventilator-dependent people for communication. Some additional therapies turn out to be symptomatic and supportive.

Treatment of myotubular myopathy or various forms of CNM happens to be largely supportive and so, there isn’t any cure. Today, researchers are studying the utilization of drugs recognized as ACE (acetylcholinesterase) inhibitors. However, more research is important for determining the long-term effectiveness and safety of ACE inhibitors for treating people suffering from myotubular myopathy.

Conclusion

Myotubular myopathy happens to be congenital, meaning the disorder remains present at birth. When respiratory insufficiency is compensated infants might survive beyond infancy, and after this, the weakness begins to seem non-progressive. As research continues in this area, newer ways of treatment of myotubular myopathy may be discovered. Nevertheless, genetic counselling before planning a baby and timely diagnosis and treatment for diagnosed cases may help a lot.

Pramod Kerkar

Written, Edited or Reviewed By:

, MD,FFARCSI

Pain Assist Inc.

Last Modified On: April 5, 2019

This article does not provide medical advice. See disclaimer

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