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Myotonic dystrophy: Prognosis and management

Basil T Darras, MD
David A Chad, MD
Section Editors
Jeremy M Shefner, MD, PhD
Douglas R Nordli, Jr, MD
Deputy Editor
John F Dashe, MD, PhD


Myotonic dystrophy type 1 (DM1) and myotonic dystrophy type 2 (DM2) are autosomal dominant, multisystem disorders characterized by skeletal muscle weakness and myotonia, cardiac conduction abnormalities, and iridescent cataracts. Immune and endocrine manifestations of myotonic dystrophy include hypogammaglobulinemia, testicular failure, and insulin resistance (insensitivity).

DM1 results from an unstable CTG repeat expansion in the DMPK gene on chromosome 19, and DM2 is caused by the expansion of a CCTG repeat of the ZNF9 gene on chromosome 3; in both diseases, the multisystem features are caused by corresponding CUG (DM1) and CCUG (DM2) expansions expressed at the RNA level [1].

In general, DM2 is a less severe disease than DM1. There are congenital, juvenile, and adult onset forms of DM1, whereas only an adult onset form of DM2 is recognized. Typically, DM1 patients come to medical attention because of mental retardation or severe muscle weakness and myotonia, whereas in DM2, the chief complaints are usually muscle pain, stiffness, fatigue, or proximal muscle weakness [1].

There is no disease-modifying therapy available for the treatment of myotonic dystrophy. Thus, treatment is symptomatic. The systemic (non-neuromuscular) manifestations of myotonic dystrophy are the most treatable aspects of the disease. Recommendations regarding management are based more on consensus and clinical experience than on evidence from randomized controlled trials.

The management and prognosis of patients with myotonic dystrophy will be reviewed here. Other aspects of myotonic dystrophy are discussed separately. (See "Myotonic dystrophy: Etiology, clinical features, and diagnosis".)


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Literature review current through: Sep 2016. | This topic last updated: May 20, 2015.
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