About Congenital Myotonic Dystrophy

Congenital myotonic dystrophy (CDM1) is a genetic disease that presents itself at birth. Patients born with CDM1 might have deformed feet, might not be able to breathe or feed properly and might be considered 'floppy' as an infant due to delayed development of muscles. It can affect many parts of the body and can lead to significant physical and cognitive impairment and, in some cases, early death. The most challenging symptoms of MMD1 include:

  1. difficulty with thinking and problem solving;
  2. weakened muscles; and,
  3. speech, hearing and vision difficulties.

Diagnosis is confirmed though a diagnostic evaluation or genetic test.

There are currently no approved therapies for CDM1 and patients are typically treated with drugs to address different symptoms of the disease. Many patients also receive support through special education and speech and physical therapy.

Our clinical development program in congenital myotonic dystrophy

AMO-02, one of AMO Pharma's lead investigational drugs, is in development for the treatment of congenital myotonic dystrophy, (myotonic dystrophy is the most common form of muscular dystrophy (DM1). It is caused by a mutation in the DMPK gene. Congenital myotonic dystrophy symptoms include muscle weakness and intellectual, sleepiness and developmental impairment.

The safety and efficacy profiles of this therapy and its demonstrated mechanism of action provide strong support for its development in this indication and for potential use in the treatment of certain other orphan and non-orphan diseases.

A phase 2 proof-of-concept study found AMO-02 provided clinical benefit to the majority of subjects after 12 weeks of treatment. Improvements were most evident in cognitive functioning, fatigue and ability to perform activities of daily living, as well as in certain neuromuscular symptoms. In addition, co-occurring autism symptoms improved in several subjects. AMO is now advancing AMO-02 to a Phase 2/3 registration-caliber study in children and adolescents with congenital myotonic dystrophy. The study is intended to commence later this year, conducted at multiple sites across North America and in the UK.

Resources for more information about myotonic dystrophy

There are several organizations available to provide information about myotonic dystrophy and the services available to help families:

Myotonic Dystrophy Foundation

Myotonic Dystrophy Support Group

Muscular Dystrophy Association

Muscular Dystrophy Association UK

Congenital Myotonic Dystrophy

In addition, many countries now have patient registries for myotonic dystrophy. For additional information on resources and to access a DM family and patient registry, please visit:

Norwood FL, Harling C, Chinnery PF, Eagle M, Bushby K, Straub V. Prevalence of genetic muscle disease in Northern England: in-depth analysis of a muscle clinic population. Brain. 2009 Nov;132(Pt 11):3175-86. PubMed PMID: 19767415; PubMed Central PMCID: PMC4038491.