DefinitionMuscular dystrophy is a group of inherited disorders that involve muscle weakness and loss of muscle tissue, which get worse over time.Alternative NamesInherited myopathy, MDCauses, incidence, and risk factorsMuscular dystrophies, or MD, are a group of inherited conditions, which means they are passed down through families. They may occur in childhood or adulthood. There are many different types of muscular dystrophy. They include:Becker muscular dystrophyDuchenne muscular dystrophyEmery-Dreifuss muscular dystrophyFacioscapulohumeral muscular dystrophyLimb-girdle muscular dystrophyMyotonia congenitaMyotonic dystrophySymptomsSymptoms vary with the different types of muscular dystrophy.All of the muscles may be affected. Or, only specific groups of muscles may be affected, such as