Myotonic Dystrophy Type 1 and Type 2
Synonyms
Myotonic dystrophy type 1 [OMIM #160900]; Dystrophia myotonica 1; DM1; Steinert’s disease; Myotonic dystrophy type 2 [OMIM #602668]; Dystrophia myotonica 2; DM2; Proximal myotonic myopathy; PROMM
Definition and Characteristics
Myotonic dystrophy (dystrophia myotonica, DM) is the most common inherited muscular dystrophy in adults. DM1 and DM2 show similarities in their clinical features including progressive myopathy, myotonia and multiorgan involvement. Both myotonic dystrophies are dominantly inherited disorders caused by repeat expansion mutations.
Clinical symptoms and signs in DM1 comprise three different phenotypes: (i) the most common adult onset DM1 with clinical myotonia, distal and facial weakness and atrophies, cataracts, cardiac conduction defects, frontal baldness, endocrinological, liver and skeletal abnormalities and CNS involvement with sleepiness, personality and cognitive changes. Later patients develop incapacity, dysphagia, respiratory failure and have a...
References
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