Disease Information for Myotonic Dystrophy

Disease Information

Understanding Myotonic Dystrophy

Myotonic dystrophy (DM*) is an inherited disorder that can affect many systems in the body, including skeletal muscle, breathing, cardiac performance, cognitive function, and multiple other organs and systems.  Symptoms of this complex disorder vary from individual to individual, even within the same family, making the disease difficult to diagnose and treat.

Two types of myotonic dystrophy have been identified.  The first type, referred to as DM1 is the most common form of adult-onset muscular dystrophy.  This form affects an estimated 1 in 8,000 people worldwide or 40,000 people in the US alone. The second type, DM2 produces many symptoms similar to DM1, but is caused by a different genetic defect.  To date there have been no large scale or definitive studies to determine the prevalence of DM2.  Other possible types, caused by different genetic mutations, are currently being investigated. 

The key for dealing with this disorder is education for both families with myotonic dystrophy and the health professionals who treat them. Please read on to learn about the different types of myotonic dystrophy, its symptoms, diagnosis, and treatment, commonly asked questions, and much more.

  • If you are newly diagnosed, please visit our Newly Diagnosed page and read our message about how to empower yourself as you navigate your new circumstances.
  • For an overview of myotonic dystrophy, we recommend you start with About the Disease. Here you can learn about the different types of myotonic dystrophy, its origins and the wide range of symptoms people experience.
  • To help you sort through the vast array of information you may be processing, we've also included a Medical Glossary, Frequently Asked Questions, and a Resources and Links page which contain other helpful information.
  • To find more technical details about the disease, go to the Professionals page.

*  "DM" is the most commonly accepted acronym for myotonic dystrophy and derived from the Latin name, dystrophia myotonica.