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AUTUMN 2025 InTouch | 13 Little is known about the function of dystrophin in brain 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. DUCHENNE MUSCULAR DYSTROPHY (DMD) normally. Muscular weakness and skeletal abnormalities such as scoliosis (curvature of the spine) frequently contribute to breathing disorders. Cardiomyopathy (enlarged heart) occurs in almost all cases, beginning in the early teens in some, and in nearly all after the age of 18 years. Intellectual impairment or learning difficulties may occur, but this is not inevitable and does not worsen as the disorder progresses. With treatment advances over the years, young men with DMD are able to live longer and more fulfilling lives and many are able to complete their education and obtain employment. Several treatments have now been approved with more in the clinical trial phases. What causes DMD? The DMD gene is the largest known human gene. It provides instructions for making a protein called dystrophin. Defects in this gene result in markedly reduced or absent production of dystrophin. The dystrophin protein is located primarily in muscles used for movement (skeletal muscles) and in heart (cardiac muscle). Small amounts of dystrophin are also 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 fibres and protect them from injury as muscles contract and relax. The dystrophin complex acts as an anchor, connecting each muscle cell’s structural Little is known about the function of dystrophin in brain 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. What are the Genetics of DMD? The sex chromosomes X and Y determine if a baby will be a boy or a girl. DMD is caused by a defect in the dystrophin gene, which sits on the X chromosome. One functioning copy is enough to prevent DMD. Girls receive an X frommum and an X from dad and their family to have the condition. This is because the error in the gene has occurred randomly. This is called a de novo mutation (new and not inherited). Genetic counselling is available to families who have had a diagnosis of DMD. This service helps families understand inheritance patterns and what this means in their family. They can also explain reproductive options available enabling people to make more informed family- planning decisions. Carrier testing of female family members can be arranged if desired. Continued over ... 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 signalling by interacting with proteins that send and receive chemical signals. 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. are described as XX. Boys receive an X frommum and a Y from dad and are described as XY. As boys have only one X chromosome, if they inherit an X chromosome with the non-functioning dystrophin gene, then they will have DMD. The mother is described as a carrier and with one functioning dystrophin gene is usually unaffected. A carrier mother has a 25% chance in each pregnancy of having an affected male child and a 25% chance in each pregnancy of having a carrier daughter. Approximately 1 in 3 boys with DMD will be the only person in