Muscular dystrophy refers to a group of inherited genetic conditions characterized by progressive muscle weakness and degeneration. The underlying cause varies by type; in Duchenne muscular dystrophy (DMD), for instance, a mutation in the dystrophin gene results in the absence of a protein essential for muscle fibre integrity, but the shared feature across all types is the progressive loss of muscle tissue and function over time.
The rate of progression, the muscles affected, and the age of onset differ considerably between types. What they have in common is the absence of any treatment that stops or reverses the underlying degeneration.
Common long-term consequences of muscular dystrophy include:
- Progressive muscle weakness, beginning in specific muscle groups depending on the type, and spreading over time to affect mobility, upper limb function, and eventually respiratory and cardiac muscles
- Loss of ambulation, many patients lose the ability to walk independently in their early teens; others retain mobility into adulthood, depending on the subtype
- Respiratory complications, as the muscles involved in breathing weaken, patients become dependent on ventilatory support
- Cardiac involvement, cardiomyopathy, is a significant complication in several MD subtypes, including Duchenne and Emery-Dreifuss
- Scoliosis, spinal curvature resulting from trunk muscle weakness, which can further compromise respiratory function
- Contractures, progressive shortening of muscles and tendons that restricts joint movement
- Fatigue and pain, chronic muscle inflammation, and the effort required to compensate for weakened muscles contribute to significant daily fatigue
These consequences accumulate over the years, placing a significant burden on patients and their families. The rate of decline varies, but the direction, without intervention that addresses the underlying biology, is consistent.