Muscular Dystrophy Onset and Progression: Correcting the Age Myth

The claim that muscular dystrophy "typically appears between ages 5 and 20 and progresses rapidly" is false and dangerously oversimplified.

Muscular Dystrophies Are a Heterogeneous Group

Over 30 genetic disorders with varying onset, progression, inheritance, and affected muscles.

Duchenne is the most common severe childhood form → historically overrepresented. But "muscular dystrophy" ≠ Duchenne.

Genetic testing essential for precise diagnosis, prognosis, family counseling.
Multidisciplinary care (neurology, PT, cardio, pulmonary, ortho) improves lifespan/quality.
New therapies (exon skipping, gene therapy, CRISPR) are type-specific.

Never generalize. Each dystrophy has a distinct natural history.

Type	Onset	Progression	Inheritance
Duchenne (DMD)	2–5 yrs (boys)	Rapid: wheelchair by 12, death 20s–30s	X-linked recessive
Becker (BMD)	5–25+ yrs	Slower, variable	X-linked recessive
Myotonic (DM1)	Any age (often 20s–30s)	Slow, multisystem	Autosomal dominant
Facioscapulohumeral (FSHD)	Teens–40s	Slow, asymmetric	Autosomal dominant
Limb-Girdle (LGMD)	Childhood–adulthood	Variable (rapid to slow)	AR / AD
Congenital (CMD)	Birth/infancy	Variable	AR
Oculopharyngeal (OPMD)	40s–60s	Slow	Autosomal dominant