What is the role of dystrophin in Duchenne? Duchenne is caused by alterations in the dystrophin gene. The dystrophin gene is responsible for the production of a protein called dystrophin. Dystrophin has an important role in the structure and function of muscles, acting as a shock absorber, protecting muscle fibres during repeated muscle contraction or stretch. The absence of dystrophin affects the muscle’s ability to function correctly, resulting in progressive muscle degeneration and loss of muscle strength. Dystrophin is present in all muscle cell membranes serving as a “coat hanger” around which other proteins associate. Dystrophin is a key molecule that helps form a link between the internal structure of the cell and the extracellular matrix (proteins and carbohydrates that surround a cell). When dystrophin is absent or non-functional, the so called Dystrophin Associated Protein Complex doesn’t function correctly, interrupting a number of functions. The role of dystrophin can be explained like a boat being held in place by an anchor. Without dystrophin the muscle is not secured, leaving it vulnerable to damage. Figure 1 - Muscle cells are made from muscle fibres with dystrophin, along with other proteins holding the muscle fibre and muscle cell membrane together. In Duchenne muscular dystrophy the absence of dystrophin means the muscle cannot function correctly, leaving the muscle vulnerable to progressive damage and muscle wasting. Figure 3 - Some of the results of absent or non-functional dystrophin production in Duchenne muscular dystrophy.