According to a story from sciencemag.org, an experimental gene therapy for the rare genetic disorder X-linked myotubular myopathy is starting to produce significant improvements for patients. A devastating disease that inflicts severe weakness practically from birth, patients in a clinical trial of the therapy are now able to sit on their own, and some are even breathing without help from a ventilator. Such results could indicate a major breakthrough in the treatment of this rare neuromuscular disease.
About X-Linked Myotubular Myopathy
X-linked myotubular myopathy is a form of centronuclear myopathy. With an X-linked recessive inheritance pattern, boys are almost exclusively affected by the disorder. The disease is linked to mutations affecting the MTM1 gene. In most cases, the defining symptom is severe, extreme muscle weakness and lack of muscle tone. In some patients symptoms may be milder but this is by far the exception. Other symptoms include distinctive facial features, long digits, and abnormal patterns of growth. Difficulty with breathing and feeding because of weak muscles is often noticeable within the first few days or weeks of life. Prompt, supportive intervention is critical as the muscle weakness associated wih X-linked myotubular myopathy can be fatal. Most patients pass away by the teenage years unless they have a milder presentation. Treatment for X-linked myotubular myopathy is symptomatic and supportive. To learn more about X-linked myotubular myopathy, click here.
About The Study
The trial was sponsored by Audentes Therapeutics and included a total of nine boys with the disease. The participants ranged between eight months and six years of age. The gene therapy used in this study used a AAV viral vector in order to delivery the corrected gene. Three patients had serious side effects, but these were all addressed and treated effectively.
A biopsy 48 weeks after treatment showed that the boys were producing myotubularin (the substance that is absent in patients) at 85 percent of the rate found in healthy people. The results have been incredible, with four of the patients sitting on their own and three even beginning to take steps (with assistance). Some are making sounds for the very first time.
This is another example of the potential that gene therapies have to offer for patients with rare genetic diseases such as X-linked myotubular myopathy.