Small amounts of dystrophin are present in nerve cells in the brain. In skeletal and cardiac muscles, dystrophin is part of a group of proteins a protein complex that work together to strengthen muscle fibers and protect them from injury as muscles contract and relax.
The dystrophin complex acts as an anchor, connecting each muscle cell's structural framework cytoskeleton with the lattice of proteins and other molecules outside the cell extracellular matrix. The dystrophin complex may also play a role in cell signaling by interacting with proteins that send and receive chemical signals. Little is known about the function of dystrophin in nerve cells. Research suggests that the protein is important for the normal structure and function of synapses, which are specialized connections between nerve cells where cell-to-cell communication occurs.
More than 2, mutations in the DMD gene have been identified in people with the Duchenne and Becker forms of muscular dystrophy. These conditions occur almost exclusively in males and are characterized by progressive muscle weakness and wasting atrophy and a heart condition called dilated cardiomyopathy.
Most of the mutations that cause these conditions delete part of the DMD gene. Other mutations abnormally duplicate part of the gene or change a small number of DNA building blocks nucleotides in the gene. Mutations that cause Becker muscular dystrophy, which typically has milder features and appears at a later age than Duchenne muscular dystrophy, usually lead to an abnormal version of dystrophin that retains some function. Mutations that cause the more severe Duchenne muscular dystrophy typically prevent any functional dystrophin from being produced.
Skeletal and cardiac muscle cells without enough functional dystrophin become damaged as the muscles repeatedly contract and relax with use. The damaged cells weaken and die over time, causing the characteristic muscle weakness and heart problems seen in Duchenne and Becker muscular dystrophy. More than 30 mutations in the DMD gene can cause an X-linked form of familial dilated cardiomyopathy. This heart condition enlarges and weakens the cardiac muscle, preventing the heart from pumping blood efficiently.
Although dilated cardiomyopathy is a sign of Duchenne and Becker muscular dystrophy described above , X-linked dilated cardiomyopathy is typically not associated with weakness and wasting of skeletal muscles.
The mutations that cause X-linked dilated cardiomyopathy preferentially affect the activity of dystrophin in cardiac muscle cells. Dystrophin is a protein found in muscle cells. It is one of a group of proteins that work together to strengthen muscle fibers and protect them from injury as muscles contract and relax.
Duchenne is caused by mutations to the dystrophin gene. Because of this error in the genetic instructions, cells cannot make dystrophin, a protein muscles need to work properly. Without dystrophin, muscle cells are damaged, and, over time, are replaced with scar tissue and fat in a process called fibrosis.
Our goal is to make Duchenne. By completing a 10 minute survey, you can help us learn what topics interest you most. Type in your search and hit return. Understanding the role of dystrophin in Duchenne. These frame-shift mutations result in production of little or no functional dystrophin, leading to a cycle of muscle cell degeneration, inflammation and fibrosis characterized by loss of muscle mass and muscle wasting. Some patients with DMD can still produce a tiny amount of dystrophin in their bodies—but often at such low levels that it can only be detected using highly sensitive imaging techniques.
Sign up for news from Sarepta Therapeutics, including product updates, reimbursement information, and services that may be of interest to you and your patients. This indication is approved under accelerated approval based on an increase in dystrophin in skeletal muscle observed in some patients treated with EXONDYS Continued approval for this indication may be contingent upon verification of a clinical benefit in confirmatory trials.
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