Answers to questions families often have about caring for their child with Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a progressive form of muscular dystrophy that occurs primarily in boys. It is caused by an alteration (mutation) in a gene called the DMD gene, which can be inherited in families; however, DMD often occurs in people from families without a known family history of the condition. In individuals with DMD, muscle fibers break down. They are replaced by fibrous and/or fatty tissue that cause the muscle to gradually weaken, leading to progressive loss of muscle function, which begins in the lower limbs.

DMD is inherited in an X-linked recessive pattern. Males have only one copy of the X chromosome from their mother and one copy of the Y chromosome from their father. If their X chromosome has a DMD gene mutation, they will have Duchenne muscular dystrophy. Females, on the other hand, have two copies of the X chromosomes. Since females have two copies of this gene, if one copy does not work, they have a second backup copy to produce the dystrophin protein. A woman who has a genetic change in one of her two copies is said to be "a carrier" of Duchenne muscular dystrophy. Carriers do not have Duchenne muscular dystrophy, and most are unaware that they even carry this change in their genetic material unless they have a family history of DMD.

The symptoms usually appear before age 6 and may appear as early as infancy. Motor milestones, such as when the child first walks, may be delayed. Boys may have a waddling gait and difficulty climbing stairs. Calf muscles are usually noted to be enlarged. There is a steady decline in muscle strength between the ages of 6 and 11 years; treatment with steroids helps to alleviate some of this progression. Scoliosis, a curvature of the spine, may appear. Muscular weakness and skeletal deformities frequently contribute to breathing disorders. Cardiomyopathy (enlarged heart) begins after the age of 18 in most, but some will experience this in the early teen years. Few individuals with DMD live beyond their 30s. Breathing complications, subsequent infection, and cardiomyopathy are common causes of death.

Unless there is a family history of Duchenne, most boys are not diagnosed until they start displaying symptoms. Sometimes, a blood test for high-protein levels called creatine kinase is used to screen for DMD. Creatine kinase is normally found in muscle, but leaks into the bloodstream when muscles are abnormal, like in DMD. DMD is confirmed by genetic testing. Different types of genetic tests can provide specific and more detailed information about the DNA mutation. Genetic confirmation is crucial for determining if your son qualifies for clinical trials and helping your family with decisions related to prenatal diagnosis and future pregnancies. Your doctor may also recommend a muscle biopsy, which is the process of taking a small sample of muscle to analyze the amount of dystrophin protein present in the muscle cells.

With high standards of medical care, young men with Duchenne muscular dystrophy often live well into their 30s. Progressive weakness first shows as difficulty climbing stairs, then walking, until a wheelchair is needed for all mobility. Early treatment with steroids may help prolong life and the ability to walk. Upper limb function and maintenance of good posture become increasingly difficult, and complications, such as scoliosis and heart problems, can occur. Some boys with DMD will also develop learning and/or behavioral difficulties.

Several ongoing clinical trials for boys with specific gene mutations with Duchenne muscular dystrophy can be found at Explore Clinical Trials. Parent Project Muscular Dystrophy. Genetic testing is important to be able to participate in these trials. It is encouraged to register your child in your respective National Duchenne Patient Registry.

The likelihood of a mom who is a carrier of DMD passing the gene to a child is different for males and females because DMD is an X-linked recessive condition. So, females carrying the changed gene copy have a 50% chance of passing it on with each pregnancy. Thus, there is a 25% chance of having an affected child with DMD, a 50% chance of boys having DMD, and a 50% chance that girls will be carriers. The chance of a woman who has 1 affected son and no family history of being a carrier of the changed DMD gene is approximately 2/3. For more information, talk to your neurologist, geneticist, or genetic counselor.

Prednisone, a type of steroid, is given to improve strength and function, prolonging the ability to walk by 2 to 5 years. Possible side effects of prednisone include weight gain, high blood pressure, behavior changes, and delayed growth. Boys with DMD need to be monitored closely. A synthetic form of prednisone, Deflazacort, is used in Europe and believed to have fewer side effects than prednisone. Otherwise, treatment for Duchenne muscular dystrophy is aimed at the symptoms. For instance, dilated cardiomyopathy is managed with anti-congestive medications, and braces may help contractures that develop in the legs. Input from specialists in many different areas is best. Guidelines for treatment are available at Duchenne/Becker Muscular Dystrophy. Treat NMD (Neuromuscular Network).

Discussions depend on family preferences and the age and cognitive level of the boy with DMD. Starting these conversations earlier is typically better, as is having many conversations over the years as your child gains understanding or hears new information. Sometimes, boys with DMD already understand a fair amount without being told. The first step, therefore, is to determine his level of understanding. Try avoiding negative words associated with DMD, such as “bad or “bad illness.” It is also important to introduce the words “Duchenne” or “DMD” early on to help your child learn about the condition. An opportunity to attend a muscular dystrophy camp where the boy can meet other children with DMD and see boys in various stages is often helpful. Since research on DMD is progressing quickly, discussions should hold out hope for the future. Ultimately, do not be afraid to say the “wrong” thing. There are opportunities to fix mistakes; it is better to be honest and transparent instead of avoiding conversations about DMD. Adjusting to the Diagnosis (Parent Project Muscular Dystrophy) has helpful information.

There are various types of external catheters used primarily by men with spinal cord injuries. Although many providers worry about the risk of infection and skin irritation/breakdown with these systems, many users are quite satisfied. To find a provider familiar with the use of catheters and the possible side effects, call a local rehabilitation facility with expertise in spinal cord injury, and ask for an appointment with a provider familiar with them.

Starting early, around the age of 13 or 14, to develop a plan can be helpful. Consider goals for education, employment, housing, transportation, and mobility, along with transitioning care to adult providers. Also, consider mental health. Adults with Duchenne can experience anxiety and depression. Mental health screening should occur during visits with the multidisciplinary team and treated accordingly. See Transition to Adult Healthcare.