What Is Emery-Dreifuss Muscular Dystrophy?

Emery-Dreifuss muscular dystrophy is a type of muscular dystrophy (an inherited condition of muscle weakness and muscle wasting). The condition affects the body’s muscles, including the heart. 

This form of muscular dystrophy can be inherited in several ways. Experts aren’t sure how many people worldwide have this kind of rare muscular dystrophy.

Some estimates suggest that about 250,000 people in the U.S. live with this form of muscular dystrophy. Other estimates are much more conservative, putting the number between 300 to 3,000.

This article will take a closer look at Emery-Dreifuss muscular dystrophy, describing the symptoms, causes, diagnosis, treatment, and prognosis for the condition.

Emery-Dreifuss Muscular Dystrophy Symptoms

The main symptoms of Emery-Dreifuss muscular dystrophy include:

• Muscle weakness, often in the arms and legs
• Muscle wasting (the muscles shrink) 
• Contractures (hardening of muscles that causes joint rigidity and deformity) 
• Heart issues 
  

Symptom severity can vary significantly and isn’t the same for everyone with Emery-Dreifuss muscular dystrophy.

Common locations for muscle contractures include the following:

• Achilles tendon (joins the calf muscles to the heel at the back of the lower leg)
• Spine 
• Elbows 
  

Age of onset also differs. Some people can develop symptoms in childhood, while others may only start to experience symptoms in adulthood. However, most people develop symptoms as children.

Children with this type of muscular dystrophy might walk differently to make up for muscle weakness in the legs. As the disease progresses, they may have more difficulty with day-to-day movements, such as going up and downstairs. 

Because the heart muscle is also affected, people may experience the following additional symptoms:

• Fatigue
• Difficulty exercising 
• Heart palpitations
• Irregular heartbeat 
• Conduction block (problems with the heart's electrical system), which can cause several issues such as trouble breathing and blackouts
  

Causes

Like other types of muscular dystrophy, Emery-Dreifuss is caused by genetic mutations. These have been identified in the following genes:

• EMD
• FHL1
• LMNA
  

These genes are involved in both skeletal and cardiac muscle function. Skeletal muscles are the ones you use to move your body. The heart is made up of cardiac muscle. When these genes malfunction, they lead to problems with both types of muscles.

In more than half of the cases of Emery-Dreifuss muscular dystrophy, there are no changes in EMD, FHL2, or LMNA, so other gene mutations may be involved. Experts have yet to identify other potential gene mutations that may contribute to this condition.

There are several ways for a person to inherit the genes that cause Emery-Dreifuss muscular dystrophy.

X-Linked Recessive Pattern

X-linked recessive means that the mutated gene (usually EMD or FHL1) is on the X chromosome. People who inherit only one X chromosome and a Y chromosome (often identified as male at birth) only need one copy of the mutated gene (which must come from their maternal parent ) to develop the condition.

In people who inherit two X chromosomes (who most often are identified as female at birth), the mutation must be present in both copies of the gene to cause the condition. Sometimes, people with two X chromosomes can have a single copy of the mutated gene, which can cause some but not all symptoms of Emery-Dreifuss muscular dystrophy.

Autosomal Dominant Pattern

In this case, a single copy of the mutated gene is enough to cause muscular dystrophy. Most often, the LMNA gene is involved in this pattern of inheritance. The gene mutation occurred spontaneously in the person affected about 65% of the time and wasn't passed down from a parent.

Autosomal Recessive Pattern

This inheritance pattern is rare for Emery-Dreifuss muscular dystrophy. In this condition, it typically involves both parents being carriers of the mutated gene (having only one copy and not displaying the condition).

Autosomal means the gene is carried on a chromosome that is not the X or Y chromosome. Recessive means the person needs two copies of the gene mutation to develop the condition, receiving one from each parent.

Diagnosis

In many cases of X-linked Emery-Dreifuss muscular dystrophy, contractures are the first sign that something is wrong, prompting someone to seek a diagnosis. For autosomal dominant cases, people will typically experience muscle weakness before contractures.

Healthcare providers diagnose the condition based on a combination of clinical signs and genetic testing. 

Signs that may prompt genetic testing include:

• Contractures
• Muscle weakness and wasting that get worse over time
• Heart disease and other heart issues
• Family history of the disease
  

Treatment

While there’s no cure for Emery-Dreifuss muscular dystrophy, it’s possible to manage symptoms and improve quality of life.

Treatment for heart problems can include:

• Antiarrhythmic drugs
• Implantation of a pacemaker (an implanted device that regulates the heart rhythm)
• Cardioverter defibrillator implant (an implanted device that triggers to correct a dangerous heart rhythm)
• Heart transplant
• Respiratory therapy
• Ventilation (breathing support)
• Monitoring heart health

Other supportive measures include mobility aids and physical therapy to help with contractures.

Prognosis

Emery-Dreifuss muscular dystrophy is a progressive degenerative genetic condition. Unlike some other forms of muscular dystrophy, it can progress slowly, though the rate of degeneration varies.

Most people don’t develop rapid degeneration until they reach their 30s. Some people may lose the ability to walk.

People with this type of muscular dystrophy often develop heart problems in young adulthood. But these problems can occur earlier or later.

Summary 

Emery-Dreifuss muscular dystrophy is a rare progressive genetic condition that causes skeletal and heart muscle problems. It is inherited, but the inheritance pattern varies.

Unlike other types of muscular dystrophy, it progresses slowly. Some people might not even develop symptoms or receive a diagnosis until they reach young adulthood. There’s no cure for the condition, but it’s possible to manage symptoms. 

A Word From Verywell

If you live with Emery-Dreifuss muscular dystrophy, working with a care team is crucial for managing symptoms and ensuring good quality of life.

Living with a progressive degenerative disease like this one can be overwhelming. You may find it helpful to reach out to support groups and disease-specific organizations. They can help you connect to others, find out about new advances in treatments, and find resources such as financial aid.