Why are muscle fibres replaced by fat and scar tissue in muscular dystrophy?

In muscular dystrophy, the replacement of muscle tissue with fat and scar tissue is a consequence of the disease's progressive nature. These hereditary conditions arise from genetic mutations that disrupt the production of essential proteins required for normal muscle structure and function.1

The pathology involves a cycle of muscle fiber degeneration followed by attempts at regeneration. While some fibers may initially regenerate and become larger than normal, this process eventually fails. As the disease progresses, the damaged muscle fibers are progressively lost and are replaced by fibrous scar tissue and fat cells. This process, which leads to a permanent loss of muscle strength and function, is a hallmark of the condition's advancement. In some forms of the disease, such as Duchenne muscular dystrophy, this deposition of fat can even lead to pseudohypertrophy, where the muscle appears enlarged despite the loss of functional muscle fibers.123