Myotonic Dystrophy Type 2: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Myotonic Dystrophy Type 2?
A neurologist (a doctor who treats diseases of the nerves and muscles) usually treats myotonic dystrophy type 2. An eye doctor may notice the cataracts that come with it and refer a person to a neurologist. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is myotonic dystrophy type 2?
Myotonic dystrophy is part of a group of inherited disorders called muscular dystrophies. It is the most common form of muscular dystrophy that begins in adulthood.
There are two major types, type 1 and type 2. The two types overlap, although type 2 tends to be milder than type 1.
Myotonic dystrophy affects at least 1 in 8,000 people worldwide.
Symptoms
Myotonic dystrophy causes muscle wasting and weakness that get worse over time. In type 2, weakness mainly affects muscles near the center of the body. Examples are the neck, shoulders, elbows and hips.
Other signs and symptoms can include these.
- Myotonia, which means muscles are slow to relax after use. For example, a person may find it hard to let go of a doorknob.
- Muscle pain, which in type 2 may be brought on by exercise, touch or changes in temperature.
- Cataracts, which are clouding of the lens of the eye. They are common in type 2 and often appear by middle age.
- Daytime sleepiness.
The heart can also be affected. Some people have problems with the electrical signals that control the heartbeat. Some people develop diabetes, which means high blood sugar.
Causes and who gets it
Type 2 results from changes in the CNBP gene. A segment of DNA in the gene is repeated too many times. This stops muscle cells and cells in other tissues from working normally.
Type 2 is inherited in an autosomal dominant pattern. That means one copy of the altered gene in each cell is enough to cause the disorder. In most cases, an affected person has one parent with the condition.
Signs of myotonic dystrophy often begin in a person's twenties or thirties. They can occur at any age.
How doctors diagnose it
A doctor who suspects myotonic dystrophy type 2 starts with your history and a physical exam. The next step is a DNA test, also called a genetic test. It needs only a blood sample.
Finding extra repeats of DNA in the CNBP gene can confirm type 2. This applies when the type 1 test is negative and the doctor strongly suspects it.
- An electromyogram (EMG) uses small needles in the muscles to measure electrical activity.
- An electrocardiogram (ECG), a test of the heart's electrical signals, can find heart rhythm problems that cause no symptoms.
- A muscle biopsy has a limited role. It can help tell type 2 from an inflammatory or metabolic muscle disease.
Treatment
Care works best with a team. Doctors recommend watching and managing the many symptoms together.
- Heart care. Everyone with myotonic dystrophy should have regular heart checks. Pacemakers and implantable defibrillators can treat abnormal heart rhythms.
- Myotonia. If myotonia is bothersome, a drug called mexiletine can treat it. Mexiletine can rarely cause heart rhythm problems in people who already have them. It is best to see a heart doctor before you start it.
- Cataracts. They can be removed with surgery if they get in the way of daily life.
Low-intensity exercise is recommended, along with gentle stretching. Check with a heart doctor before starting an exercise program.
Before surgery, tell the whole medical team that you have myotonic dystrophy. Tell the anesthesia team most of all. Reactions to anesthesia do not seem as serious in type 2, but caution is advised.
Follow your doctor's instructions about every medicine.
When to see a doctor
Doctors check people with myotonic dystrophy for palpitations (a racing or skipping heartbeat), blackouts and shortness of breath. Some heart rhythm problems in myotonic dystrophy can be very serious and can even cause sudden death. For this reason, people with myotonic dystrophy need regular ECGs.
Call 911 or go to the emergency room if you have chest pain lasting two minutes or more, severe trouble breathing, fainting or loss of consciousness.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. A direct primary care doctor can review your symptoms and refer you to a neurologist. They can also help coordinate care among specialists and keep up with follow-up visits.
Common questions
Is myotonic dystrophy type 2 milder than type 1?
Yes, type 2 tends to be milder than type 1. The two types are caused by changes in different genes.
Is myotonic dystrophy type 2 inherited?
Yes, it is inherited in an autosomal dominant pattern. One altered copy of the CNBP gene in each cell is enough to cause it.
What is myotonia?
Myotonia means the muscles cannot relax easily after use. For example, a person may have trouble letting go of a doorknob.
Can myotonic dystrophy type 2 affect the heart?
Yes, both types can affect the heart, although complications seem more common in type 1. The most common problem is an abnormal heart rhythm.
How is myotonic dystrophy type 2 diagnosed?
Doctors diagnose myotonic dystrophy type 2 with your history, a physical exam and then a DNA test from a blood sample. An ECG, a test of the heart's electrical signals, is also important for finding heart rhythm problems.
Sources
- MedlinePlus Genetics - Myotonic dystrophy
- Muscular Dystrophy Association - Diagnosis of Myotonic Dystrophy
- Muscular Dystrophy Association - Medical Management for Adult-Onset DM1/DM2 and Juvenile-Onset DM1
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
