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Neuromuscular diseases

Myotonic dystrophy type 1 (DM1, Steinert disease)

An inherited muscle disease. The muscles become weak and do not relax easily after contracting. The eyes, heart and hormones can also be affected.

Not part of the panel of Türkiye's National Newborn Screening Programme (heel-prick test). Source

Orphanet has a guideline for emergency doctors for this disease (language: French, Polish, German, English, Spanish, Italian). See on Orphanet

Prepare an emergency card

This page is translated from the Turkish original.

This disease is followed through the “Neuromuscular diseases” group.

Understanding the disease

This section has not yet been reviewed by a physician. It summarises patient information from sources such as MedlinePlus, Orphanet and the NHS in plain language. The disease can differ from person to person; talk to your doctor about diagnosis and treatment.

What happens in this disease?

The disease is caused by a change in the DMPK gene. A piece of DNA in the gene is repeated many more times than normal. This disrupts how cells in the muscles and other tissues work. The muscles, heart rhythm, lens of the eye and hormones can be affected.

Which symptoms can occur?

Symptoms often begin in a person's 20s or 30s. There is also a severe type present from birth and a mild type.

  • The muscle being unable to relax after contracting, called myotonia; for example, being unable to let go of a door handle
  • Weakness in the muscles of the face, neck, hands and lower legs
  • Drooping eyelids and slurred speech
  • Clouding of the lens of the eye at an early age, called cataract
  • Heart rhythm and conduction problems
  • Excessive daytime sleepiness and tiredness
  • Difficulty swallowing and digestive problems
  • An increased risk of diabetes

How is it diagnosed?

The doctor examines the person and asks about the family history. The diagnosis is made with a genetic test that looks at the DMPK gene. EMG, blood tests and heart tests may also be done.

Treatment and care

There is not yet an approved treatment specific to the disease; research is ongoing. Care is planned according to the organs affected. The heart is checked regularly; if needed, devices such as a pacemaker are fitted. Cataracts can be corrected with surgery. Physiotherapy, occupational therapy and assistive devices make daily life easier. Breathing support during sleep may be needed. Procedures that need anesthesia are planned with an experienced team. The doctor who follows the disease decides which treatment is suitable.

For the family: inheritance and genetic counselling

The disease is passed on through dominant inheritance. For each child of an affected parent, the chance is 1 in 2. As the gene passes from one generation to the next, the number of repeats can increase. This is why symptoms in children can begin earlier and be more severe. The type present from birth is more common in babies of mothers who carry the disease. Genetic counselling helps the family understand these risks.

Source: MedlinePlus Genetics: Myotonic dystrophy · NORD: Myotonic Dystrophy · Orphanet: Steinert myotonic dystrophy (ORPHA:273)

Key facts

How common is it?
Prevalence: 1-9 per 100 000 (Europe)
How is it inherited?
Autosomal dominant
When does it usually start?
Adolescence, Adulthood, Before birth, Childhood, Infancy, Newborn period

These facts are taken from Orphanet and MedlinePlus records (last checked: October 7, 2026). Frequency values are approximate ranges.

You are not alone: patient associations in Türkiye

Non-profit patient and family organizations in Türkiye working on this disease or disease group. Links are for information; Doktorclub is not affiliated with these organizations and does not endorse them.

For all rare diseases: Nadir Hastalıklar Federasyonu

Links checked on October 8, 2026.

Guides related to this disease

  • Home care and medical devices · Home health service, oxygen and respiratory device reports, wheelchairs and orthoses, power outage notification, emergency plan.
  • Rare disease at school · Telling the school, medicines and emergency plan, inclusion and BEP, support education room, absences, LGS/YKS arrangements, peer bullying.

Support and help

Doktorclub does not diagnose, recommend treatments or refer you to hospitals or doctors. These pages are meant to help you talk with your doctor.

News about Myotonic dystrophy

Clinical trials (ClinicalTrials.gov)

A clinical trial is a regulated study that tests whether a new treatment is safe and whether it works, in patients who volunteer. Most trials look for a certain age, genetic change and health condition. Taking part is voluntary.

This list is not a treatment recommendation. Treatments tested in phase 1–3 trials are investigational (experimental): their efficacy and safety have not yet been proven and they are not approved treatments. Taking part depends on each trial’s criteria and a physician’s assessment; the first step is to talk to the doctor who manages your care.

Questions you can ask your doctor

  • Could this trial be suitable for us?
  • If we take part, how would current treatment and check-ups be affected?
  • Where does the trial take place, and how are travel and accommodation handled?
  • What happens if we want to leave the trial?

ClinicalTrials.gov lists 26 active interventional studies for this disease. 16 are recruiting now; none has a site in Türkiye. Last checked: October 7, 2026.

Selected records (studies with a site in Türkiye first):

See all studies on ClinicalTrials.gov · Joining clinical trials

Neuromuscular diseases: other news

Medical codes (for talking with your doctor and finding sources)

These codes identify the disease in international classifications and databases. They can help when you talk with your doctor or look for reliable sources.

Orphanet code: ORPHA:273

No separate ICD-11 code; WHO classifies this disease under: 8C71.0

Codes checked against WHO ICD-11 and Orphanet on October 7, 2026.

This page provides general information and does not replace diagnosis or treatment. Talk to your doctor about symptoms, diagnosis and treatment.

The information on these pages is for general information only and does not replace medical advice. Talk to your doctor about diagnosis and treatment decisions. In an emergency in Türkiye, call 112.

Every update is based on an open source and labeled with its level of evidence. No advertising and no drug brand names. Our scientific principles

This page was translated from Turkish by the Doktorclub editorial team.