Symptoms of DMD start in early childhood. Often, the first noticeable sign is a delay in reaching developmental milestones, like walking well by 18 months of age or sitting or standing without assistance.
Duchenne muscular dystrophy (DMD) is a genetic disorder that results in muscle wasting and weakness over time. Symptoms of DMD might start by age 2, but it can take several years for your doctor to diagnose.
The first noticeable sign of DMD is often when your child doesn’t reach developmental milestones when expected, like walking well by 18 months of age, and lifting their head, sitting, or standing without assistance.
While these signs won’t always mean your child has DMD, it’s important to have them evaluated by a doctor as soon as you notice them. Your doctor will need to perform additional testing, including a muscle biopsy and genetic testing to confirm a diagnosis.
If your child has DMD, treatment is more effective when it’s started in the early stages of the condition.
Symptoms of DMD aren’t noticeable at birth. The earliest symptoms of DMD might begin to be noticeable during the first 3 years of life.
Delays in reaching developmental milestones
A delay in meeting developmental milestones may be the first noticeable sign of a muscle problem. Milestones are the skills or tasks a child can do by a certain age.
Milestones will vary from child to child, but most children follow a similar order and pattern. Children with DMD may have a delay in the following milestones:
- lifting their head while lying on their tummy
- rolling over on their own
- sitting or standing without assistance
- walking well by 18 months
Toddlers with DMD may seem awkward and clumsy. They might bump into things and fall over frequently.
Difficulty rising from a sitting position (Gower’s sign)
When getting up from a sitting position, your child may first start on their hands and knees and then slowly walk their hands up the shins, knees, and thighs until standing.
This is called
Children with DMD may walk on their toes or the balls of their feet.
Children with DMD may walk with a waddling motion. This is called
Children with DMD may have larger than normal calve muscles. This is caused by scarring in the muscles.
Speech and cognitive problems
Children with DMD may have problems with speech and language development. They may start speaking much later than their peers. In some cases, delayed language milestones may be the earliest sign of DMD.
Older research from 2008 suggests that children with DMD also experience learning or intellectual disabilities, like attention deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), and autistic spectrum disorder, at higher rates than the overall population.
Over time, weakness in the muscles progresses until the use of a wheelchair is necessary.
Some of the later signs and symptoms may include:
- curvature of the spine (scoliosis)
- contracture, which occurs when your muscles, tendons, or joints, which are normally stretchy, tighten or shorten and become non-stretchy; a contracture is usually permanent and can cause significant disabilities
- loss of the ability to walk, typically around 12 to 14 years of age
By the late teens, DMD may also cause serious, life threatening complications affecting the heart and the muscles used for breathing.
Effects on the heart
Problems with the heart muscles can make it harder for the heart to pump blood (cardiomyopathy). The heart can become enlarged. This may eventually lead to heart failure.
Effects on the lungs
Another complication of DMD is weakness of the muscles in the rib cage. This can make it harder to breathe. The weakness also increases the risk of serious respiratory infections like pneumonia. At this stage, a ventilator might be necessary to help with breathing.
Effects on digestion
If the muscles of the gastrointestinal tract are affected, food may move through the digestive tract too slowly. This can cause constipation or diarrhea. At advanced stages of DMD, it might also become difficult to swallow (dysphagia).
DMD symptoms are often managed by a team of specialists, including a neuromuscular specialist, physical therapist, speech therapist, occupational therapist, cardiologist, and pulmonologist.
There’s currently no cure for DMD. Treatment involves managing symptoms. This may include:
- medications such as corticosteroids, which are used to help muscle function
- newer agents called antisense oligonucleotides, which may be used in children whose DMD is caused by specific genetic mutations
- physical therapy
- use of mobility aids like canes, braces, or wheelchairs
- breathing assistance
Researchers are also working to develop newer gene therapies that can halt or reverse muscle loss and greatly increase life expectancy.
The earliest signs of DMD may begin appearing around age 2, but symptoms vary from child to child. These signs may be subtle and don’t mean your child has DMD. Talk with your doctor if you think there’s something wrong with the pace and manner your child is developing.
Though muscular dystrophies like DMD aren’t common, in the rare case that your child does have DMD, early diagnosis and treatment can help delay muscle loss and help your child reach their full potential.