Frequently asked questions

Myotonic dystrophy (DM) is a genetic disorder that can affect many parts of your body. DM is a complex condition, and its symptoms and disease progression can vary widely from person to person – even among members of the same family. This means it can be challenging to predict just how DM will affect you and your loved ones. For example, one person may have mild muscle stiffness or develop cataracts later in life, while another person may be born with serious breathing problems (Hawkins et al., 2019; Henke et al., 2020) or develop problems with their heart (Freyermuth et al., 2016; Wahbi et al., 2016).

There are two types of myotonic dystrophy: myotonic dystrophy type 1 (DM1) and myotonic dystrophy type 2 (DM2). DM1 is further categorized based on the age at which symptoms first appear.

Myotonic dystrophy type 1

This is the most common form of the disease, affecting an estimated 1 in 2,100 people worldwide. That is over 3.6 million individuals across the world (Johnson et al., 2021).

There are three categories of DM1, categorized by when symptoms of the disease first appear:

• Congenital myotonic dystrophy (CDM)
  • “Congenital” means present at birth. In CDM, symptoms are noticeable from birth. Babies with CDM may face significant health challenges early on and often require specialized medical care right away. Delivery at a medical center with high-risk neonatal support may be recommended.
• Juvenile-onset myotonic dystrophy
  • For individuals with Juvenile-Onset DM1, symptoms usually appear during childhood or adolescence, before the age of 21. The first signs are often related to learning difficulties or challenges with intellectual development. These signs can present during childhood or adolescence (before age 21).
• Adult-onset myotonic dystrophy
  • Adult-Onset DM1 is diagnosed after the age of 21. Symptoms can vary but common ones include muscle weakness, muscle wasting (loss of muscle mass), and stiffness. These symptoms can develop gradually.

Click here to view MDF’s consensus-based clinical care guidelines for DM1.

Additionally, comprehensive information for clinicians is regularly updated here: https://www.ncbi.nlm.nih.gov/books/NBK1165/

Myotonic dystrophy type 2

DM2 was discovered more recently, in 2001. The exact number of people who may have this type of DM is currently unknown. Symptoms of DM2 often manifest in adulthood and can affect multiple body systems. The most common symptoms are muscle pain and fatigue.

Click here to view MDF’s consensus-based clinical care guidelines for DM2.

Additionally, comprehensive information for clinicians is regularly updated here https://www.ncbi.nlm.nih.gov/books/NBK1466/.

Myotonic dystrophy type 1 is the most common form of the disease. An estimated 1 in 2,100 people worldwide carry the repeat expansion that can cause the disease. That is over 3.6 million individuals across the world (Johnson et al., 2021).

While genetic studies are currently underway, it is currently unknown how many people are living with myotonic dystrophy type 2. The prevalence appears to differ across various populations; however, few definitive demographic studies have been conducted. A higher prevalence of DM2 is observed in Germany, Czechia, Serbia, and Poland and in individuals of German or Polish descent. For example, in Finland, the incidence of DM2 (1:1,830) is higher than that of DM1. In Germany, cumulative empirical evidence suggests an estimated prevalence of DM2 of roughly 9:100,000; therefore, DM2 is as prevalent as DM1.

Scientists and Physicians often use Latin when naming different diseases or organisms. So, while the disease is called myotonic dystrophy – it is abbreviated “DM” after the Latin name, which is dystrophia myotonica.

You might also hear other names used by doctors and researchers worldwide:

• DM: Myotonic Muscular Dystrophy (MMD)
• DM1: Steinert’s Disease
• DM2: Proximal Myotonic Myopathy (PROMM)

Muscular dystrophy (MD) refers to a group of genetic diseases that cause progressive weakness and degeneration of muscles used during voluntary movement. Myotonic dystrophy (DM) is one of the muscular dystrophies. It is also the most common form seen in adults and is suspected to be among the most common forms overall.

Myotonic dystrophy is an inherited disease that is passed from one generation to the next through a faulty gene. It is not caused by an infectious agent such as a virus or bacteria, or chemicals, biohazards or similar exposures.

Learn more about genetics and DM

Myotonic dystrophy can be diagnosed clinically, by a doctor familiar with the disease, who recognizes the symptoms in a person. Or, more definitively, through genetic testing.

If you have a family history of myotonic dystrophy (DM), or if your symptoms include signs like early onset cataracts, difficulty relaxing your grip (myotonia), muscle pain or gastrointestinal issues, your doctor might suggest genetic testing. A genetic test uses a blood sample to check for the presence of expanded repeats in the genes that cause myotonic dystrophy.

Usually, an individual seeking genetic testing is either someone with symptoms, someone with a clinical DM diagnosis (when your doctor believes your symptoms are consistent with DM but this has not been verified through a genetic test), seeking a second opinion or confirmation, or someone without symptoms or a diagnosis but with a family history of DM.

Genetic testing for DM uses DNA testing methods to check for the presence of an abnormally expanded repeat in the DMPK gene for DM1, or an abnormally expanded repeat in the CNBP gene for DM2. Types of genetic testing used to diagnose DM are called “southern blot”, “Polymerase Chain Reaction” or “PCR” for short, or genetic sequencing.

It is important to note that not all genetic tests and testing providers will tell you your repeat number or repeat size, the number of expansions you have on the DMPK or CNBP gene. Instead, some tests will just say you have more repeats than the threshold, and therefore a positive test result.

A genetic test for myotonic dystrophy must be ordered by a physician.

Genetic Counselors help families navigate the process of genetic testing, provide education about your diagnosis, and can help you make informed and very personalized decisions about testing and family planning. A genetic counselor may also support your physician in ordering a genetic test, and finding a testing laboratory.

Because DM is such a rare and variable disease, many community members find themselves traveling quite far to see a specialist or educating their more local doctors and clinicians. Because of this, MDF has a variety of toolkits to educate your family and your doctors on DM. Click here to find a list of resources and links for both yourself, and your medical team.

It is very easy to connect to other people living with DM by joining one of MDF’s many support groups, Facebook Pages, or even in person events like conferences! Our support groups are facilitated by trained community volunteers and create a safe space for those living with DM to share, learn, and connect.

You can see a list of all of our support groups and facebook pages here.

You may also be interested in joining us for an in person conference, find out more here.

It is very easy to connect to other people caring for loved ones living with DM by joining one of MDF’s many support groups, Facebook Pages, or even in person events like conferences! Our support groups are facilitated by trained community volunteers and create a safe space for those living with DM to share, learn, and connect.

You can see a list of all of our support groups and Facebook pages here.

You may also be interested in joining us for an in person conference, find out more here.

Living with myotonic dystrophy can affect more than just your physical health; DM can also influence how you think, feel, and interact with others. While research in this area is still ongoing, mental and emotional changes are a real part of living with DM. You may notice shifts in your mood, motivation, energy, or social comfort, and these experiences are valid and common in the DM community.

There are many ways to support your emotional well-being. Taking an active role in your mental health can make a meaningful difference in your day-to-day life, no matter the severity of your symptoms. MDF’s Myotonic Dystrophy and Mental Health Handbook provides a detailed, community-focused overview of common mental health symptoms and treatment options, along with recommendations from mental health and neuropsychology experts.

For individuals living with myotonic dystrophy (DM), heart or “cardiac” issues can pose a serious threat to health because the heart is itself a muscle and is affected by many of the muscular dystrophies. People living with myotonic dystrophy type 1 (DM1) or type 2 (DM2) can experience cardiac issues. Annual appointments with a cardiologist and regular monitoring is recommended for people living with DM. There are management techniques, including procedures to implant a pacemaker or an Implantable Cardioverter Defibrillator (ICD), that can be used to support your heart health.

Learn more about DM and heart health and risk.

When the muscles in the intestines are weak or don’t work well together, it can be harder for food and waste to move through the digestive system the way they should. This is known as dysmotility, which means the muscles aren’t coordinating properly. As a result, things might move too slowly or too quickly through the gut. This can lead to irregular bowel movements, like constipation and diarrhea, as well as stomach pain and bloating (Hilbert et al., 2017; Peterson & Cooper, 2022).

Because of DM, over time, the muscles used for speech and facial expressions may weaken or become rigid, which can lead to difficulties with communication, chewing, and swallowing. Addressing muscle weakness early, through support like physical and speech therapy can significantly help these symptoms before they worsen. Use the Speech and Language Guidelines to work with a speech pathologist on techniques to support your ability to swallow. You may also be interested in MDF Cooks, a cook book with recipes for folks who struggle with dysphagia.

Research shows that moderate exercise is safe and beneficial in people with DM and can support overall health without worsening disease progression (Voet NB, et al., 2019) (Cup EH, et al., 2007) (Orngreen MC, et al., 2005) (Roussel MP, et al., 2019). However, it is important not to overexert yourself. Before starting an exercise program, individuals with DM should consult with a physical therapist or neurologist who has knowledge about DM or neuromuscular diseases for an evaluation. Exercise can help maintain joint health, support heart and lung function, improve balance, and even reduce certain types of pain you may experience related to muscle imbalance or tightness. Together with your therapist, you will develop goals that match your symptoms, lifestyle, and priorities.

Learn more about exercise and movement for those living with DM.

Physical therapy can play an important role in helping you maintain mobility, strength, and comfort while living with myotonic dystrophy. Physical therapists (PTs) also called Physiotherapists in Canada, the UK, Australia, New Zealand, India, and other countries around the world, specialize in assessing movement and function and can design individualized exercise programs tailored to your needs. They may also recommend orthotics (such as braces or splints) or adaptive equipment to support your balance, safety, and independence.

There are four types of exercise recommended for people living with DM:

• Flexibility/Stretching/Range of Motion
• Aerobic/Cardiovascular
• Resistive/Strengthening
• Balance Training

Be sure to work with a physical therapist to develop a weight lifting or resistive training regiment that works for you!

The Social Security Administration (SSA) doesn’t include myotonic dystrophy on the list of chronic illnesses or impairments provided in its Blue Book, it’s guide for detailing specific medical impairments that automatically qualify people for disability benefits. DM is not included in the Blue Book in part because the disease is variable and not all DM patients are unable to work, making a blanket determination impossible, and partially because DM is such a difficult disease to understand. If any of the following, or other common DM symptoms, prevents you from working, you might qualify for Social Security disability benefits:

• Depression
• Difficulty with walking and other motor skills
• Difficulty seeing
• Difficulty concentrating or completing simple tasks
• Inflammatory bowel disease, including digestive disorders/weight loss and pseudo-obstructions
• Difficulty remembering
• Extreme fatigue, regardless of sleep
• Speech impairment
• Trouble breathing or lung infections
• Persistent or recurrent heart problems, including arrhythmias
• Side effects of medication(s)

You can review the Social Security and Disability Toolkit to find more information about the application process.

You may also consider reaching out to the Patient Advocate Foundation (PAF) to work with a free case worker to support you in applying to disability and other programs.

There are many ways to navigate this challenge. First, you can appeal to your insurance and ask for them to make an exception. Consider sharing MDF resources, like the Consensus Based Care Guidelines, and the Body Systems Page. that share the importance of building a knowledgeable care team.

You may also consider working with an organization like the Patient Advocate Foundation (PAF), who will provide a free case worker to navigate the appeal process. Finally, you may consider having your current care team request a consultation with existing experts outside of coverage.

Getting a result can be highly variable. Typically, once a sample is sent out for testing, a result is received within 3-4 weeks. After the results are processed, you can consult with your doctor or genetic counselor to review the results of the test.

Not always. Even though siblings share many of the same genes, differences in their overall genetic makeup can affect which organs are impacted, when you experience symptoms, and how the disease changes over time.

A repeat expansion is a mutation or a genetic change in your DNA where a short DNA sequence is copied too many times. Myotonic dystrophy is a repeat expansion disease. Because the repeat can also increase in size over time, these mutations are also called “instable”.

In DM1, expansion happens in the Dystrophia Myotonica Protein Kinase (DMPK) gene. This gene normally contains a small number of repeat made up of the letters C, T, G. Most people have between 5 and 37 CTG repeats. In people with DM1, this CTG repeat becomes much longer than normal, with 50 to more than 4,000 repeats.

In DM2, expansion happens in a gene called the CCHC-type zinc finger nucleic acid binding protein (CNBP) gene (also sometimes called ZNF or CNBP1). This gene normally contains a small repeated DNA pattern made up of the letters C, C, T, G. Most people have fewer than 75 repeats, while people with DM2 may have anywhere from 75 to more than 11,000 CCTG repeats.

In both DM1 and DM2, these expanded DNA repeats cause the gene to produce abnormal RNA with long stretches of repeats, which interferes with how cells function.

Watch the “Ask-the-Expert: Genetics & myotonic dystrophy” to learn more

You deserve the best care possible as you navigate your DM journey. Because myotonic dystrophy affects many parts of the body, it is beneficial to have a team of different specialists who work together to support your care. Building a care team allows you to play an active role in managing your health and can help prevent potential complications.

Most people with DM find a neurologist, or a neuromuscular neurologist to manage their care, as well as a cardiologist and a primary care provider. Additionally, you may consider seeing a variety of specialists each year including: , pulmonologist, gastroenterologist, physical therapist and more.

You can talk to your neurologist about building out a comprehensive care team, get referrals to specialists, and ensuring your doctors are communicating with each other.

Find more about who is included in your treatment team on our working with your healthcare team page. Reach out to the MDF warmline to help find a doctor near you!

Bring MDF Consensus Based Care Guidelines to ensure your doctors are up to date on the best practices for supporting someone with DM.

• Clinical care recommendations for adults with DM1
• Clinical care recommendations for adults with DM2

Find all resources for you and your healthcare professional here.

Excessive Daytime Sleepiness (EDS) is common in people with myotonic dystrophy and can happen at any age. EDS is different from regular fatigue because it can make you fall asleep often, and sometimes without warning, during the day even if you sleep a normal amount or more at night. If you are struggling with symptoms related to sleep, talk to your care team. Your provider will give recommendations on potential medications or devices. They can also help you decide if it may be beneficial to see a sleep medicine doctor who may request a sleep study (an overnight test that tracks your breathing, heart rate, and sleep patterns to check for sleep problems).

There are existing medications that may help with EDS. Talk to your doctor about ways to manage excessive daytime sleepiness.

While it is a very hopeful time in DM research, it is hard to know the exact timeline for a treatment to become available. The best way to stay informed on updates for potential treatment is to review our Drug Development Pipeline and to sign up for our monthly newsletter, My Dispatch.

Anticipation is the phenomenon that with each successive generation, the symptoms of DM1 can appear earlier and become more severe (Yum et al., 2017). Anticipation occurs because the number of CTG repeats in the DMPK gene is unstable and the repeat can expand with each successive generation. Anticipation does not appear to be observed in DM2.

Yes. Genetic counselors can explain the chances of passing on the DM gene and walk you through testing options that are available. A genetic counselor can also refer you to experts in assisted reproductive technologies (ART) and fertility centers to explore prenatal testing strategies or in vitro fertilization in combination with genetic testing (preimplantation genetic testing/diagnoses (PGD). You may also consider working with a fertility specialist who can consult with you about options such as sperm banking or egg freezing. These conversations can help you better understand your options and make informed choices.

While it is not 100% error free, PGD is a highly accurate diagnostic procedure.

Myotonic dystrophy is a progressive or degenerative disease. This means that symptoms tend to worsen gradually over several decades. The prognosis of DM is as variable as the symptoms. How myotonic dystrophy affects one individual can be completely different from how it manifests in another, even for members of the same family. It is impossible to predict how the disease will affect any single individual.

While no treatment exists that slows the progression of myotonic dystrophy, management of its symptoms can greatly improve patient quality of life. Early intervention can reduce or avert complications that sometimes arise.

While there is currently no cure or specific treatments for DM, there is a lot your healthcare team and you can do to improve your quality of life and manage symptoms.

(Coming soon) MDF has published guides for individuals and families in the DM community, one for DM1 and one for DM2. Part 5 of the MDF DM2 or DM2 Guidebook goes through each body system and describes how myotonic dystrophy may impact it and what you and your healthcare providers can do to help.

MDF has published clinical care guidelines including quick reference guides to share with your doctor.

You can also share the published NIH guidelines, Gene reviews, with your doctors. These publications are written for professionals, and may be confusing for community members:

• DM1: https://www.ncbi.nlm.nih.gov/books/NBK1165/
• DM2: https://www.ncbi.nlm.nih.gov/books/NBK1165/

It is a very hopeful time in DM research with many different pharmaceutical companies and academic institutions researching a treatment or cure for DM. To see the current drug development efforts, review our Drug Development Pipeline here.

There are many ways to support DM research. If you are interested in participating in Clinical Trials or studies, you can see all of the current studies and trials in our Studies and Trial Resource Center.

You can also find more information on Clinicaltrials.gov.

Join the DM Family Registry to help advance DM research and share knowledge about the impacts of DM.

Donate to MDF to fund research for treatment and a cure.