The expected lifespan for a male with DMD has improved significantly in the past two decades. Most young men will live into their earlier or mid-twenties. Respiratory infections become an increasing problem as their breathing becomes weaker, and these infections are usually the cause of death.
The course of the other muscular dystrophies is more variable; expected life spans and degrees of disability are hard to predict, but may be related to age of onset and initial symptoms. Prediction is created more difficult because, as new genes are discovered, it can be turning out to be clear that several of the dystrophies aren’t uniform disorders, but rather symptom groups brought on by numerous genes.
People with dystrophies with considerable heart involvement (BMD, EDMD, Myotonic dystrophy) may nonetheless have almost normal life spans, provided that cardiac complications are monitored and treated aggressively. The respiratory involvement of BMD and LGMD similarly require cautious and prompt treatment.