Chromosomal and Genetic Conditions
Duchenne Muscular Dystrophy
What is Duchenne muscular dystrophy?
Muscular dystrophy (MD) is a genetic condition that weakens your child’s muscles slowly over time. There are several forms of MD that may affect different sets of muscles and cause more or less weakness.
Duchenne is the most common form of MD and the most severe. First it usually affects muscles in the hips and shoulders. Later it affects muscles in the trunk, lower legs and arms. It can also weaken your child’s heart muscle and the muscles your child uses to breathe.
Duchenne happens if your child’s body cannot make a protein called dystrophin.
Dystrophin is important for muscle health.
- It helps muscle cells stay whole and keep their shape, length and strength.
- It acts as a cushion or shock absorber that helps muscles contract and relax without being damaged.
In Duchenne, there’s a problem with a gene that tells your child’s body how to make dystrophin.
Because your child is missing this protein:
- Their muscles are fragile and easily damaged.
- Their body can’t repair the minor muscle damage that normally happens day to day.
- Fat and scar tissue replace your child’s damaged muscle, making their muscles less stretchy and mobile.
- Over time, your child’s muscles become weaker.
Children with Duchenne are born with an abnormal gene for making dystrophin. But it often takes a few years or longer before a child shows any signs or symptoms that family members or doctors would notice. Most are diagnosed between age 3 and 5.
Each child with Duchenne is unique. One thing they all have in common is their muscle weakness gets worse over time.
The age when symptoms start and the speed of the change are different for each child.
- Usually, children slowly lose their ability to walk, sit up on their own and move their arms.
- Most begin using a wheelchair by about age 12.
- Later, typically in their teen years, they may start having heart problems (cardiomyopathy) or breathing problems because of weak muscles.
About 1 in 3 children with Duchenne has learning disabilities.
There is no cure yet for Duchenne, but treatment can support your child’s function and comfort so they have a rich, active life at home, at school and in the community.
Over the last 10 years a number of clinical trials have tested new medicines that might help boys with Duchenne. There are now medicines approved by the U.S. Food and Drug Administration to treat some boys with the condition.
People with Duchenne are living longer and more independently than ever before. Most live into their 20s or 30s. Many young adults with Duchenne go to college, work and get married, and some have children of their own.
Almost all children with Duchenne are boys. That’s because the gene that causes Duchenne is on the X chromosome.
Boys typically have 1 X chromosome (passed from their mother) and 1 Y chromosome (passed from their father). If they have a gene that causes Duchenne on their X chromosome, they will have this form of MD.
Girls typically have 2 X chromosomes (1 from their mother and 1 from their father). If 1 X chromosome has a gene that causes Duchenne, usually the other X chromosome has a normal gene that tells their body to make enough dystrophin.
Girls can be carriers of Duchenne, and some carriers can have mild symptoms.
A baby can get Duchenne even if both of their parents do not have the abnormal gene. When a baby is developing in the womb, a normal gene for making dystrophin can change. This happens in about 1 in 3 children with Duchenne.
Duchenne Muscular Dystrophy at Seattle Children’s
Seattle Children’s Neuromuscular Program offers the most comprehensive care in the Pacific Northwest for children with Duchenne muscular dystrophy.
- We have been named an MDA Care Center by the Muscular Dystrophy Association and a Certified Duchenne Care Center by Parent Project Muscular Dystrophy, the leading advocacy group for people with Duchenne.
- Our dedicated team – doctors, nurse practitioners, therapists, dietitians, genetic counselors and social workers – has expertise and experience in diagnosing and treating Duchenne.
- Seattle Children’s brings together pediatric specialists from Rehabilitation Medicine, Endocrinology, Neurology, Pulmonary and Sleep Medicine and the Heart Center to evaluate your child’s unique needs.
- We design and provide care to help your child and family manage Duchenne and to give your child the best possible function and quality of life now and as they grow.
- Seattle Children’s provides a full range of treatments, from medicines, therapy and equipment, to respiratory support, heart care and orthopedic surgery.
- To make sure your child has a full evaluation and receives complete, coordinated care, we will involve experts from across Seattle Children’s.
- Your child may see their entire team in one room on a single day, making the process easier on you and your child.
- Based on your child’s needs, your team may include experts from Orthopedics, Speech and Language Services, Neurodevelopmental Clinic and other specialties and programs.
Doctors and scientists at Seattle Children’s are active in research into new ways to treat Duchenne.
We took part in clinical trials that led to the approval of eteplirsen (Exondys 51), the first drug that treats one of the genetic changes that cause the disease.
Our active clinical trials program means your child may have the chance to receive promising new therapies by taking part in research that matches their specific situation.
Seattle Children’s scientists are also involved in lab research to help develop new drugs for Duchenne.
To learn more about neuromuscular research at Seattle Children’s, email us.
Symptoms of Duchenne Muscular Dystrophy
Children with Duchenne usually seem to develop and move like other children their age for at least their first couple of years. Symptoms often start between age 3 and 5.
You may notice changes in the way your child walks, including:
- Stumbling, falling or seeming clumsy
- Walking on their toes or the balls of their feet
- Walking with their chest or belly pointing out and their shoulders pulled back
Getting up from the floor may become harder for children with Duchenne. To make it easier, your child might:
- Roll onto their belly.
- Raise their bottom in the air.
- Walk their hands up their legs until they’re standing.
Your child might also begin having trouble:
- Going up or down stairs
- Pushing or raising their arms
- Lifting their head or neck
As more of your child’s muscles become weaker, your child may develop other symptoms or conditions related to Duchenne, such as trouble walking, trouble sleeping, tiring easily and scoliosis.
Diagnosing Duchenne Muscular Dystrophy
Your child’s doctor will most likely schedule a clinic visit to:
- Ask you about your child’s symptoms, development and medical history.
- Examine your child and look for patterns of muscle weakness.
- Blood test to check the level of an enzyme (serum creatine kinase) that is higher when muscles are damaged
- Genetic test to look for changes in the Duchenne gene
- Muscle biopsy to see whether your child’s muscle cells are abnormal and whether they have any dystrophin that works
Treating Duchenne Muscular Dystrophy
At Seattle Children’s, your child receives complete care from the team in our Neuromuscular Program – and from our other programs if needed.
We offer a range of treatments to help with your child’s strength, activity level and comfort and are involved in research on new ways to treat Duchenne.
Every child with Duchenne does not need every type of treatment. Your child’s treatment plan will be custom-made for them and will change over time as their needs change.
The Neuromuscular Program team includes experts from Rehabilitation Medicine, Endocrinology, Neurology, Pulmonary and Sleep Medicine and the Heart Center, as well as dietitians, genetic counselors and social workers.
Based on your child’s needs, we also involve specialists from other clinics and programs around Seattle Children’s, such as:
Common treatments to maintain your child’s ability to move and do the things they want to do include:
- Physical therapy to maintain muscle tone, improve range of motion and evaluate whether your child needs equipment
- Occupational therapy to help your child with activities like dressing and using a computer keyboard
- Braces for your child’s feet and legs to keep them more flexible, prevent tight muscles and joints (contractures) and extend the time your child can walk on their own
- Medicine to slow breakdown of muscles, keeping your child stronger and more active longer
- Exercise designed for your child to build their muscles and keep their heart healthy without overdoing it
- Devices that help your child get around, such as a wheelchair, or that help them with daily tasks, such as a special chair for sitting in the shower
- Surgery to release tight muscles and joints (contractures) or to treat severe scoliosis so your child can sit up or sleep more comfortably or breathe more easily
We will evaluate your child’s lung function as their breathing muscles become weaker, with a focus on preventing and treating respiratory infections.
Infections can become serious if weak breathing muscles make it hard for your child to cough out phlegm. A device called a cough-assist machine can help your child get a deeper breath and then clear their airways. A respiratory therapist sets up the machine and teaches you how to use it.
Eventually, children with Duchenne may need a machine to help with breathing (bilevel positive airway pressure, Bi-PAP). Some children start by using Bi-PAP only at night and gradually need to use it more of the time.
Your child will have a complete cardiac evaluation every 1 to 2 years to check how well their heart is working. Medicines can help your child’s heart move blood around their body with less effort. These include angiotensin-converting enzyme (ACE) inhibitors and beta blockers.
A dietitian will work with you and your child to:
- Make sure your child gets the right amount of calories to have energy and maintain a healthy weight so extra pounds don’t strain your child’s muscles.
- Prevent constipation (from weak abdominal muscles and limited movement overall) with a diet high in liquids, fiber and fresh fruits and vegetables.
- Keep your child’s bones healthy if they take corticosteroids, which can weaken bones (and cause your child to gain weight).
A social worker focuses on supporting your child and family and helps with coping, social relationships, behavior and emotions. Along with your child’s doctors, nurses and therapists, the social worker will connect you with helpful resources at Seattle Children’s and in the community.