Emery-Dreifuss muscular dystrophy
Reviewed by Emery-Dreifuss muscular dystrophy (EDMD) is a rare group of genetic disorders that cause slowly progressive muscle weakness and joint contractures and can also affect the heart and, in some people, the respiratory muscles.
EDMD can cause potentially life-threatening heart complications, sometimes without obvious warning signs. Regular heart monitoring is an important part of ongoing care.
Specialized care can help manage EDMD’s effects on movement, muscle function, and the heart. This article covers its symptoms, genetic causes, diagnosis, and treatment.
What is Emery-Dreifuss muscular dystrophy (EDMD)?
EDMD is a group of muscular dystrophies that lead to slowly progressive muscle weakness, problems with the heart’s electrical conduction system, and joint tightening known as contractures.
The different conditions included under EDMD are associated with changes in different genes, including:
- EDMD type 1, caused by changes in the EMD gene
- EDMD type 2, caused by changes in the LMNA gene
- X-linked EDMD, caused by changes in the FHL1 gene
- other, rarer forms, linked to changes in genes such as SUN1, SUN2, SYNE1, SYNE2, and TMEM43
Although these forms can differ in how they are inherited, they share the main features of EDMD. The age of onset, severity, heart involvement, and rate of progression can vary from person to person.
What are EDMD’s symptoms?
EDMD symptoms usually become apparent by age 10, although the exact age of onset can vary among different genetic forms of the disease and from person to person.
Early joint contractures
Early EDMD symptoms often include contractures, or joint stiffness and tightening. Tight Achilles tendons can cause toe-walking, while contractures in the elbows, neck, and spine can limit movement. Although contractures may not be painful, they can make sitting and walking uncomfortable.
Muscle weakness and wasting
EDMD causes slowly progressive muscle wasting and weakness, often affecting the shoulders, upper arms, and calf muscles. Weakness can also affect the hips and thighs, making walking and other movements more difficult. Some people eventually need to use a wheelchair.
Heart symptoms and complications
Heart problems in EDMD can affect the heart’s electrical system or muscle, causing abnormal heart rhythms and symptoms such as dizziness, fainting, breathlessness, or fatigue. Heart problems often develop during adolescence or adulthood, although the timing and severity can vary.
Women who carry a disease-causing FHL1 variant may develop heart problems even without muscle symptoms, and the risk can increase with age.
Heart problems can also develop without noticeable symptoms, making regular monitoring especially important. Severe heart complications can affect life expectancy.
Breathing problems
EDMD can also weaken the muscles involved in breathing, which can lead to breathing problems. These issues can disrupt sleep and may cause daytime sleepiness, fatigue, or morning headaches. They can also increase the risk of chest infections. Severe respiratory problems are generally less common in EDMD than muscle and heart involvement.
What causes EDMD?
EDMD develops due to disease-causing genetic changes, or mutations, in one of several genes.
Genes associated with EDMD
Most EDMD cases are caused by mutations in EMD, FHL1, or LMNA, though the genetic cause remains unknown in many people.
The EMD gene produces emerin, while LMNA produces lamins A and C. These proteins help support the membrane surrounding the cell’s nucleus. Mutations can disrupt this support system and impair muscle function, although the exact mechanisms are not fully understood.
FHL1 mutations affect a protein involved in maintaining muscle structure and function. These changes can contribute to the muscle and heart problems seen in EDMD.
Why symptoms and severity vary
Different genetic forms of EDMD affect different proteins involved in muscle-cell structure and function.
The severity, age of onset, and progression of symptoms can vary greatly from person to person, even within the same family. Differences can also occur among the different genetic forms of EDMD.
How EDMD is inherited
EDMD’s inheritance pattern depends on the gene involved. EMD and FHL1 are on the X chromosome. Males with a disease-causing variant are generally affected, while females may have no symptoms but remain at risk of heart problems and, less commonly, muscle involvement.
LMNA-related EDMD can affect people of any sex and is usually inherited in an autosomal dominant pattern, meaning one disease-causing gene copy is enough to cause the condition. Rarely, it is autosomal recessive, meaning two disease-causing copies are needed, one inherited from each parent.
The chart below shows the most common inheritance patterns for the main genetic forms of EDMD.
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| Type | Gene | Inheritance pattern | Inheritance details |
| Emery-Dreifuss muscular dystrophy type 1 | EMD | X-linked |
A woman with the variant has a 1-in-2 chance of passing it to each child. Males who inherit the variant are affected. An affected male passes the variant to all his daughters and none of his sons. |
| Emery-Dreifuss muscular dystrophy type 2 | LMNA | Autosomal dominant |
One disease-causing copy is enough to cause the condition. The variant may be inherited from either parent or arise as a de novo variant. An affected parent has a 1-in-2 chance of passing it to each child. |
| X-linked Emery-Dreifuss muscular dystrophy | FHL1 | X-linked |
A woman with the variant has a 1-in-2 chance of passing it to each child. Males who inherit the variant are affected. An affected male passes the variant to all his daughters and none of his sons. |
How is EDMD diagnosed?
An EDMD diagnosis involves reviewing medical and family history, assessing symptoms and muscle strength, and evaluating heart function. Tests may include:
- electromyography to help determine whether muscle weakness is caused by a problem in the muscles or nerves
- blood tests for creatine kinase (CK), a marker of muscle damage
- genetic testing to identify gene changes and help confirm an EDMD diagnosis
- a muscle biopsy when the diagnosis remains unclear or genetic testing does not provide a clear answer
Genetic testing does not identify a disease-causing change in everyone. A variant of uncertain significance (VUS) cannot confirm or rule out EDMD on its own. Specialized muscle tissue testing may provide additional information in suspected EMD– or FHL1-related cases.
A genetic counselor can help families understand test results, arrange additional testing when needed, and assess inheritance risks.
How is EDMD treated?
There is no cure or specific EDMD treatment. Care focuses on managing symptoms, maintaining mobility, supporting breathing, and monitoring and treating heart complications.
A multidisciplinary care team may include a neurologist or neuromuscular specialist, cardiologist, and other specialists as needed.
Before surgery, people with EDMD should make sure the anesthesia and surgical teams know about the diagnosis and any heart or breathing problems. Neck stiffness or jaw tightness can make intubation more difficult, so preoperative assessment and careful monitoring after surgery may be needed.
Heart monitoring and treatment
EDMD heart problems can be life-threatening and may develop without noticeable symptoms. Regular heart monitoring is important for people with EDMD, as well as female carriers.
Heart monitoring may include:
- Electrocardiograms (ECGs): to check the heart’s electrical activity and look for conduction problems
- Echocardiograms (ECHO): to assess the heart’s structure and function
- Holter monitoring: to record the heart’s rhythm over time and look for abnormalities that may not cause symptoms
Treatment for heart involvement may include:
- heart medications
- a pacemaker or implantable cardioverter defibrillator (ICD)
- a heart transplant for severe cardiomyopathy
Exercise and physical therapy
A tailored, low-impact physical therapy plan can help maintain muscle strength and joint flexibility without overworking the muscles. Exercise should not cause pain or weakness that limits everyday activities, and people should aim to feel fully recovered by the next day.
A physical therapist may recommend:
- gentle stretching to ease joint tightness and maintain mobility
- light resistance exercises to help maintain muscle strength
- low-impact aerobic activities, such as walking, swimming, or arm cycling, to support heart and lung fitness
Mobility and orthopedic support
Custom braces and shoe supports, called orthotics, can help support mobility, stability, and alignment and may reduce discomfort while walking. An orthotist can help fit the most appropriate device.
Surgery may help correct scoliosis or release contractures, although contractures can recur.
As walking becomes more difficult, mobility aids such as canes, walkers, or wheelchairs may help with getting around.
Respiratory monitoring
Regular lung function tests, such as forced vital capacity (FVC), can help monitor breathing function. FVC measures how much air a person can forcefully exhale after taking a deep breath. Sleep studies can also assess breathing during sleep.
If breathing problems develop, the care team may recommend breathing exercises, cough-assist devices, or noninvasive ventilation. Ventilation support may be particularly helpful at night.
How does EDMD progress?
EDMD usually progresses slowly, although the course can vary from person to person and among different genetic forms. Heart problems require lifelong monitoring, while muscle weakness may become more limiting over time.
Severe heart disease can affect life expectancy in people with EDMD, though many live into middle age or beyond.
A genetic counselor and care team can help explain what an identified genetic change may mean for the course of EDMD.
Living with EDMD
EDMD affects people differently. Muscle weakness can make activities such as walking, climbing stairs, lifting, and other daily tasks more difficult.
Adaptive tools, mobility aids, and other accommodations can help people remain as independent as possible. An occupational therapist can recommend home adjustments, adaptive equipment, and ways to conserve energy.
Flexible school or work arrangements may help people manage fatigue, daily activities, and medical appointments.
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