Myotonic Muscular Dystrophy (MMD)

Signs and Symptoms

Myotonic dystrophy is more than just a muscle disease. Both MMD1 and MMD2 affect several aspects of physical and mental functioning, to varying degrees and with variable scope.

The following sections discuss different problems that can occur, although many people with the disease have only some of them. Most of these symptoms can be lessened with treatment. See Medical Management for information on current therapies.

Types of Myotonic MD

The two major types of myotonic muscular dystrophy (MMD) — MMD1 and MMD2 — are both caused by genetic defects.

MMD1, the most common type, results from an abnormal DNA expansion in the DMPK gene on chromosome 19.

MMD2 arises from an abnormal expansion of DNA in the ZNF9 gene on chromosome 3.

Within MMD1 there are additional subtypes, depending on a person’s age at onset of symptoms. The age of onset is roughly correlated with the size of the DNA expansion, with larger expansions associated with earlier disease onset.


What is myotonic muscular dystrophy (MMD)?

Illustration of muscles affected by MMD (front) Illustration of muscles affected by MMD (back)

Myotonic Muscular Dystrophy


MDA leads the search for treatments and therapies for myotonic muscular dystrophy (MMD). The Association also provides comprehensive supports and expert clinical care for those living with MMD.

In this section, you’ll find up-to-date information about myotonic muscular dystrophy, as well as many helpful resources. This information has been compiled with input from researchers, physicians and people affected by the disease.

Research Briefs: FA, MG, MM, MMD1, gene therapy

Edison drugs target FA, mitochondrial diseases

Researchers Exploring Disability Perceptions

Researchers at the Psychology of Disability Lab at the University of Michigan in Ann Arbor are exploring the social identity of people with disabilities through a short, anonymous, Web-based questionnaire.

The lab's Disability Identity Project is being headed by principal investigator Adena Rottenstein, a doctoral candidate in psychology.

The study closes the week of Aug. 22, 2011.

AAN Research Briefs on DM, DMD, LGMD, MG, MMD, SMA

Below are brief reports and links to more information about neuromuscular disease research presented at the 63rd annual meeting of the American Academy of Neurology (AAN), held in Honolulu April 9-16, 2011.

MDA Conference Brings Together Researchers, Clinicians, Industry

Moving therapeutic strategies from the laboratory to clinical trials and ultimately to the market as treatments was the theme of the MDA National Scientific Conference held March 13-16, 2011, in Las Vegas.

Some 300 people attended the conference, the first in a planned series of such MDA-sponsored meetings that will emphasize new research and current medical care. The majority of presenters and many of the audience members were current or former MDA research grantees or physicians at MDA-supported clinics.

MDA Awards $13.5 Million in Research Grants

The Muscular Dystrophy Association has awarded 44 grants totaling $13.5 million to support research efforts aimed at advancing understanding of disease processes and uncovering new strategies for treatments and cures of muscular dystrophy and the more than 40 other diseases in the Association’s program.

The new grants were reviewed by MDA’s Scientific and Medical Advisory Committees, and approved by MDA’s Board of Directors at its December meeting.