Frequently Asked Questions About Myotonic Dystrophy
Below find a listing of frequently asked questions about DM and its management. If you have a question that is not answered here, please e-mail it to MDF at info@myotonic.com and we will attempt to post the answer on our site.
General Information about Myotonic Dystrophy
- What is Myotonic Dystrophy?
- What other names are there for Myotonic Dystrophy?
- What is the difference between Myotonic Dystrophy and Muscular Dystrophy?
- What are the different forms of Myotonic Dystrophy?
- How do people get Myotonic Dystrophy?
- How is Myotonic Dystrophy diagnosed?
- What is the prognosis of having Myotonic Dystrophy?
- What treatment or therapies are available for people with Myotonic Dystrophy?
- How can I help to advance research in Myotonic Dystrophy?
Information about Managing Myotonic Dystrophy
FAQ's from DM patients and family members
If you have a FAQ that is not answered here, please e-mail it to MDF at info@myotonic.com and we will attempt to answer it over time.
What Is myotonic dystrophy?
Myotonic dystrophy (DM) is a muti-systemic inherited disease that affects 1 in 8,000 people or 40,000 individuals in the US alone. Although often viewed as a muscle disease, this description is misleading. Individuals affected by DM may have many different types of issues, including skeletal muscle problems, heart function abnormalities, breathing difficulties, cataracts, issues with speech and swallowing (dysarthria and dysphagia), cognitive impairment, excessive daytime sleepiness, or diabetic symptoms. While the list of potential problems is long, one individual is unlikely to have all or even most of these symptoms.
Myotonic dystrophy is one of the most variable and complicated disorders known. The systems affected, the severity of symptoms, and the age of onset of those symptoms vary greatly between individuals, even in the same family. In general, the younger an individual is when symptoms first appear, the more severe symptoms are likely to be. However, prognosis is as variable as the symptoms of this disease.
What other names are there for myotonic dystrophy?
Myotonic dystrophy has been referred to by different names over the years:
- Myotonic muscular dystrophy - often abbreviated as MMD
- Myotonia atrophica - a Latin name, not commonly used
- Dystrophia myotonica - a Latin name used by many doctors; often abbreviated as DM. The different types of DM are often referred to as DM1, DM2, or DM3.
- DM1 is also known as Steinert's Disease, named for the German doctor who first identified this disorder in 1909.
- DM2 is also known as Proximal myotonic myopathy or PROMM.
- Myotonic dystrophy should not be confused with other disorders with similar names (e.g.myotonia congentia [Thomsen’s disease] and congenital muscular dystrophy).
What is the difference between myotonic dystrophy and muscular dystrophy?
Muscular dystrophy (MD) refers to a group of nine genetic diseases that cause progressive weakness and degeneration of muscles used during voluntary movement.
Myotonic dystrophy is one of the muscular dystrophies. It is the most common form seen in adults and is suspected to be among the most common forms overall.
What are the different types of myotonic dystrophy?
There are two well-defined types of the disease (DM1 and DM2) which have distinct but overlapping symptoms. Both DM1 and DM2 are characterized by muscle weakness and myotonia, heart abnormalities, cataracts and insulin resistance.
In general, DM2 is less severe than DM1: fewer systems are affected, patients develop the disease only as adults, and the disorder’s impact on everyday life is relatively less disruptive.
In contrast, DM1 can occur from birth to old age. Symptoms vary greatly among patients, from minor muscle pain to serious respiratory and cardiac issues. The congenital form of DM1 is the most severe version and has distinct symptoms that can be life-threatening.
A third type, DM3, has been suspected in a small group of patients. However, some debate exists as to whether these individuals represent a truly distinct category of myotonic dystrophy caused by another mutant gene or whether some unknown factors may be confounding their diagnosis.
How do people get myotonic dystrophy?
Myotonic dystrophy (DM) is an inherited disease where a change (called a mutation) has occurred in a gene required for normal muscle function. The mutation prevents the gene from carrying out its function properly.
The change is an autosomal dominant mutation, which means one copy of the altered gene is sufficient to cause the disorder. As a result, affected individuals have a 50% chance of passing on the mutated gene to their children. A child is equally likely to have inherited the mutated gene from either parent. If both parents do not have the disease, their children cannot inherit it.
The congenital form of DM1 is inherited differently from the other types of myotonic dystrophy. Children with congenital myotonic dystrophy almost always inherit the disease from an affected mother.
How is myotonic dystrophy diagnosed?
A complete diagnostic evaluation, which includes family history, physical examination, and medical tests, is typically required for a presumptive diagnosis of myotonic dystrophy. The presence of the disorder can then be confirmed by genetic testing.
The genetic test requires a sample of blood from the patient. The DNA is then extracted from the blood and analyzed to see if that person has the mutation that causes myotonic dystrophy. Prenatal testing, where the DNA of the fetus is checked for the presence of the myotonic dystrophy mutation, is also available.
Diagnosis of myotonic dystrophy is not difficult once the disorder is suspected. However, delays in diagnosis are unfortunately common. More common diseases with symptoms that mimic myotonoic dystrophy must typically first be ruled out before this disorder is considered. The symptoms are complex. Physicians may see only one or two patients with DM in their entire practice and may not be familiar with the range of ways this disease can present.
What is the prognosis of having myotonic dystrophy?
Myotonic dystrophyis a progressive or degenerative disease. Symptoms tend to worsen gradually over several decades. 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.
DM2 tends to be less severe than DM1 and has minimal impact on life expectancy. DM1 is much more variable and the prognosis for an affected individual is difficult to predict. Some people may experience only mild stiffness or cataracts in later life. In the most severe cases, respiratory and cardiac complications can be life-threatening even at an early age. In general, the younger an individual is when symptoms first appear, the more severe symptoms are likely to be.
However, prognosis is as variable as the symptoms of this disease. 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 one individual.
What treatment or therapies are available for people with myotonic dystrophy?
While no treatment exists that slows the progression of myotonic dystrophy, symptomatic treatments are available. Managing the symptoms of this disease can reduce suffering and improve quality of life for patients. Also, ongoing monitoring can avert or reduce the complications seen at critical times.
Note: Medical information available on this site is designed as general information only. The treatment options listed are not comprehensive nor are they appropriate for all patients. Patients should consult a physician or other qualified medical professional for advice on medical treatment.
Symptomatic treatments fall into four main categories:
Medications
- Antidiabetic drugs to normalize blood sugar levels and address mild diabetic symptoms
- Antimyotonic drugs (such as mexiletine) when myotonia impairs normal activities
- Nonsteroidal anti-inflammatory drugs to manage muscle pain
Rehabilitative therapy
- Physiotherapy for muscle weakness, myotonia and contractures
- Speech therapy for swallowing and pronunciation issues
- Psychiatric therapy for behavioral and psychological issues (such as attention deficit, depression and anxiety disorders)
- Individualized support for learning disabilities and cognitive delays
Devices
- Assistive devices (such as neck braces, arm and foot braces, canes, walkers, scooters, and wheelchairs) to ensure safe navigation
- Eye crutches for droopy eyelids (ptosis)
- Pacemaker or implantable cardioverter defibrillator (ICD) to address irregular heartbeat issues
- Incentive spirometry and cough assist devices to improve respiratory function
- Continuous positive airway pressure (CPAP) device to ensure respiratory sufficiency
Surgery
- orthopedic surgery for gait issues and contractures
- cataract removal
- eyelid surgery to correct droopy eyelids
However, surgery is typically used as a last resort treatment as individuals with DM have an elevated risk of complications associated with the use of anesthesia. Please see Anesthesia Guidelines for further information.
How can I help to advance research in myotonic dystrophy?
MDF actively supports research leading to the development of a cure for myotonic dystrophy. Please click here for more information on how you can get involved.