Emery-Dreifuss Muscular Dystrophy
What is Emery-Dreifuss muscular dystrophy?
Emery-Dreifuss [EM-uh-ree DRY-fuhs] muscular dystrophy (EDMD) is one of the muscular dystrophies. These are a group of rare, inherited muscle diseases (myopathies). EDMD causes weakness in your child’s shoulders, upper arms, and calves. The disease also causes stiff joints that can’t move well (contractures). Sometimes it affects the heart’s electrical system. The name of the disease refers to the two doctors who first described it in the 1960s.
Symptoms usually appear at about 10 years of age and slowly get worse. EDMD usually affects boys, but girls also can get some forms of the disease.
What causes Emery-Dreifuss muscular dystrophy?
EDMD has several forms. All of them are caused by changes (mutations) in genes that make 3 proteins in muscle cells. These proteins are part of the envelope (membrane) around the nucleus in muscle cells. The nucleus is the sac within cells that contains the genes. A mutation in any one of these proteins can cause EDMD.
Parents can pass EDMD down to their children in different ways:
The most common form of EDMD is X-linked. This means that the changed gene is on the X chromosome. Chromosomes contain genes and are in the nucleus of your cells. Only boys get this form of EDMD. Girls have two X chromosomes, one from each parent. Boys get one X chromosome from their mother and a Y chromosome from their father. Because a boy only has one copy of the changed gene, a mutation means that he will not have enough of the protein to keep his muscles working well. A girl with the gene defect usually gets enough normal protein from her other X chromosome. But she will be a carrier for the mutation and can pass it on to her children.
Another form of EDMD affects both boys and girls, and either parent can pass this form down to his or her children. The term for this kind of inherited pattern is autosomal dominant. In this case, a parent with the disease has a 1 in 2 chance of passing it on to each of his or her children.
A rare form of EDMD happens when a child inherits a mutated gene from both parents (autosomal recessive). Both boys and girls may have this form.
All 3 forms of EDMD have similar symptoms. Researchers are still trying to understand the connections between these defective proteins and the muscle weakness in EDMD.
What are the symptoms of Emery-Dreifuss muscular dystrophy?
Children usually show signs of EDMD by 10 years of age. You may first notice “toe-walking” or waddling. Common symptoms include:
- Weakness and wasting (atrophy) of muscles in the shoulders, upper arms, and calves
- Stiff joints that make it hard to move around. The joints are often in the elbow, neck, heel, and spine.
- Muscle weakness that slowly gets worse
- Fainting or fluttering heartbeat (palpitations) because of heart problems. These are usually seen by age 30.
The muscle weakness in EDMD gets worse very slowly, and many people are still able to walk late in life. Some people may eventually need a wheelchair or other help getting around.
How is Emery-Dreifuss muscular dystrophy diagnosed?
Your child’s doctor will start by taking a health history, and ask about recent symptoms, past health conditions, and family health history. The doctor will do a physical exam. Your child may need tests, including:
- Blood tests, for muscle enzymes such as creatine kinase
- DNA blood tests, for EDMD changes
- Electromyography, to measure the electrical activity of the muscles
- MRI, to see the pattern of muscle damage
- Muscle biopsy, to look at the muscle cells or confirm a diagnosis
- Electrocardiogram, to look for possible effects on the heart
Your child may first see his or her primary doctor and later be referred to a neurologist. Some neurologists have special training to treat neuromuscular diseases such as EDMD. Your child may also need to see other providers such as cardiologists and physical therapists. Your child’s doctor may also refer your child to an MDA clinic. This place has a healthcare team trained to help treat with this disease.
How is Emery-Dreifuss muscular dystrophy treated?
Treatment for EDMD focuses on supportive treatment. Physical therapy is a key part of managing the condition. Your child may need certain treatments, such as:
- Range-of-motion and stretching exercises. These help limit problems with stiff joints.
- Surgery to release contracture. This may also help with mobility. Your child may need several surgeries.
- Heart medicine to treat cardiomyopathy
- Pacemakers or other heart devices. These lower the risk for sudden cardiac arrest.
- Breathing devices such as a ventilator machine. Your child may need these if his or her breathing muscles are affected.
What are the complications of Emery-Dreifuss muscular dystrophy?
Heart problems are the most common complication in EDMD. Most people with the condition have some heart problems by age 30. People with EDMD need to be closely monitored. Problems can include:
- Irregular heartbeat. This is caused by problems sending electrical signals from one part of the heart to another. It can cause slowed heartbeat or missed heartbeats. Your child will need checkups at least once a year for irregular heartbeats or other heart problems. This is true even if your child has no symptoms. Your child may need a pacemaker or an implantable cardioverter defibrillator (ICD) to reduce the risk for complete heart block or sudden cardiac arrest.
- Stretched and weakened heart muscle (dilated cardiomyopathy). This can make it hard for the heart to pump enough blood through the body. Your child may need medicine such as beta-blockers or angiotensin-converting enzyme (ACE) inhibitors.
- Muscle weakness. This usually gets worse over time. It may spread to involve the hips and other muscles throughout the body.
- Stiff joints that are difficult to move (contractures). Your child may need aids such as canes, braces, a walker, or a wheelchair.
- Breathing problems. These are caused by weakened breathing muscles. A positive pressure respirator can help give your child enough air flow.
Key Points about Emery-Dreifuss muscular dystrophy
- EDMD is a rare genetic muscle disease that slowly causes weakness in the shoulders, upper arms, and calves. It also causes stiff joints.
- EDMD usually shows up at about 10 years of age. The most common form of EDMD only affects boys, but other forms affect both boys and girls.
- Heart problems are common in EDMD. A child with EDMD needs to be tested at least every year. You may need medicines or devices such as a pacemaker.
- Physical therapy can help keep flexibility and range of motion.
Tips to help you get the most from a visit to your child’s healthcare provider:
- Know the reason for the visit and what you want to happen.
- Before your visit, write down questions you want answered.
- At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you for your child.
- Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are.
- Ask if your child’s condition can be treated in other ways.
- Know why a test or procedure is recommended and what the results could mean.
- Know what to expect if your child does not take the medicine or have the test or procedure.
- If your child has a follow-up appointment, write down the date, time, and purpose for that visit.
- Know how you can contact your child’s provider after office hours. This is important if your child becomes ill and you have questions or need advice.