# Duchenne muscular dystrophy
What is it
Duchenne muscular dystrophy (DMD) is an inherited muscle disease in which muscles gradually become weaker and break down. It is caused by a defect in the gene that codes for an important protein called dystrophin. This protein keeps muscle cells stable and allows them to function properly.
The disease occurs almost exclusively in boys. This is because the gene is located on the X chromosome. Boys have one X chromosome, so if this gene is damaged, they have no healthy copy to compensate for the deficiency. Girls have two X chromosomes, so usually they have a healthy copy available.
DMD belongs to a group of inherited muscle diseases that cannot be cured. The muscles weaken steadily, and this has consequences for how the body functions. It is a disease that demands much attention from the child and the family, both medically and practically.
Causes
Duchenne muscular dystrophy is caused by a mutation in the DMD gene on the X chromosome. This gene instructs the body to produce dystrophin. This protein is found in muscle cells and acts as a kind of 'anchor' that connects the inside of the muscle cell to the outside. Without working dystrophin, muscle cells cannot hold up well during contraction, and they break down and die.
Mutations in the DMD gene can arise in different ways:
- **Inherited**: The gene is passed from mother to son. Mothers can be carriers without having symptoms themselves, because they have two X chromosomes.
- **New onset**: In about one third of cases, the mutation occurs for the first time in the mother or arises spontaneously during the formation of sperm cells in the father.
Because the X chromosome in boys is the only copy, any mutation in the DMD gene automatically leads to the disease.
How the disease progresses
DMD is a progressive disease, meaning it gradually gets worse. The disease usually follows a predictable pattern, although the speed varies from person to person.
**Early childhood (2-5 years)**
The first symptoms usually appear around the second to third year of life. The child begins to lose strength and coordination. Beginning in the pelvis and upper thighs, the child finds it difficult to get up from the ground, climb stairs, or run. The movements can seem awkward and the child falls more often.
**Middle childhood (5-12 years)**
Muscle weakness spreads to more muscle groups. The child becomes dependent on aids: first canes or walkers, later a rollator, and eventually a wheelchair. During this period, many children remain active and participate in school life, although adjustments become increasingly necessary. Also the heart muscle and breathing muscles sometimes begin to deteriorate, which is not always noticeable.
**Puberty and teenage years (12-20 years)**
Weakness in the arms, trunk, and neck increases. The child becomes more fully dependent on the wheelchair and needs increasing support for daily activities. The heart muscle and lungs can cause more problems. Also muscle inflammation and fatty infiltration (where muscle tissue is replaced by fatty tissue) increase.
**Adulthood (20+ years)**
With good care, young people and young adults with DMD can live longer than before. However, muscle weakness is now severe. Many young people are fully wheelchair-dependent and need help with virtually all activities. The greatest threats are heart problems and breathing problems.
Symptoms by phase
**Early symptoms (age 2-5 years)**
- Slow or late walking (often not until after the second year of life)
- Difficulty jumping, running, or climbing stairs
- Frequent falls
- Difficulty getting up from the ground (the child 'climbs' up his own legs)
- Thicker calves than normal (because muscle is replaced by fat and scar tissue)
- Tiring easily
- Slow speech development sometimes
**Progressive Muscle Weakness (age 5-12 years)**
- Weakness in legs becomes noticeably worse
- Contractures (shortening of muscles and tendons), especially in feet and knees
- Orthopedic problems such as extended feet or spinal curvatures
- Muscle weakness reaches arms and neck
- Weak neck, difficulty holding head upright
- Breathing restrictions (especially noticeable during exertion)
- Possible first signs of heart problems (without symptoms)
**Further Progression (age 12+ years)**
- Complete dependence on wheelchair
- Weakness in arms and hands becomes severe
- Difficulty speaking and swallowing may occur
- More frequent breathing problems, especially at night
- Heart rhythm disturbances or heart muscle weakness
- Back problems and posture deteriorate
What it means for daily life
DMD has major consequences for the child's life and the family. These go far beyond just the medical aspects.
**Mobility and Independence**
As the muscles weaken, the way the child can move around and be independent changes. At first, walking aids are needed. Later, a wheelchair becomes necessary. This means adjustments at home (ramps, stairlifts), at school and in social life. Many activities that require mobility become more difficult or impossible.
**Care and support**
The care needs grow significantly as the disease progresses. Initially, help with certain tasks is needed; later, intensive daily support is unavoidable. This puts a strain on family members and often means professional home care is necessary.
**School and Education**
Many children with DMD attend regular schools, but need adapted facilities and support there. As the disease progresses, participation in school activities becomes increasingly difficult. Some children need home schooling.
**Mental Health**
The diagnosis and disease progression can be psychologically burdensome. Children and teenagers struggle with loss of possibilities, being different from peers and uncertainty about the future. Counselling from psychologists or social workers helps here.
**Family and relationships**
The disease affects the whole family. Parents carry heavy care burdens; brothers and sisters grow up in a family where much attention goes to the sick sibling. Financial burdens from medical care and adjustments can be substantial.
**Heart Function and Breathing**
These are the most serious long-term threats. The heart muscle can weaken (cardiomyopathy), and the breathing muscles can deteriorate. This can cause nighttime breathing problems, fatigue and ultimately respiratory failure. Regular check-ups and sometimes supportive devices (such as nighttime ventilation) then become important.
**Nutrition and Swallowing**
In later stages, swallowing and eating problems can develop due to weakness of the swallowing and tongue muscles. This requires caution with eating and drinking, and sometimes adjustments in diet or nutritional supplements.
Outlook
It is important to be honest: Duchenne muscular dystrophy is a progressive disease with no cure. The muscles will continue to weaken. However, thanks to improved medical care, supportive therapies and new treatments, young people with DMD nowadays live much longer than a few decades ago.
**Survival and Life Expectancy**
Research from supportive countries shows that many boys with DMD now reach their twenties, thirties or even early forties. This is much longer than was previously common. However, the prognosis varies greatly from person to person and depends on factors such as the exact mutation, how well the heart and lungs cope, and the quality of care.
However, survival figures say nothing about an individual's future. One person can perform much better than average numbers suggest, another may decline faster. This is not predictable.
**New Treatments**
Research is constantly being conducted into treatments that can slow the disease or relieve symptoms. This includes, among others:
- Medicines that fight inflammation and slow muscle damage
- Techniques that help the body produce dystrophin in other ways
- Therapies targeting the heart
- Supportive treatments for breathing and nutrition
This means that children diagnosed with DMD today may benefit from treatments still in development.
**Quality of life**
Although the disease progresses, many young people with DMD can lead meaningful lives with the right support. They can go to school, build friendships, pursue interests and participate in family life. Quality of life depends greatly on the available care and how well the medical team, school and family can work together to remove barriers.
Frequently asked questions
**Can my child prevent DMD or can it be cured?**
No, DMD cannot be prevented — it is congenital. There is currently no cure. However, the disease can be managed with medical care that relieves symptoms and slows progression. Research into new treatments continues.
**How often does my child need to see a doctor?**
Children with DMD need regular check-ups — usually several times a year. This includes check-ups by a muscle specialist (neurologist), cardiologist, lung specialist and possibly others. The frequency depends on age and how the disease progresses. Regular check-ups help detect heart and breathing problems early.
**Can my other children get DMD?**
This depends on how DMD occurred in your family. If the mother is a carrier (meaning she carries the mutated gene), each of her children has a 50% chance of inheriting the gene. Boys who inherit the gene will develop DMD; girls who inherit it are usually carriers without symptoms. A genetic counselor can explain this accurately for your situation.
**What can I do now to help my child?**
This is something to discuss with your medical team. In general, regular medical check-ups, physical activity adapted to your child's abilities, healthy nutrition, and good psychological and practical support help. The doctor can also advise on which tests and treatments are appropriate.
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_This information never replaces a doctor's judgment. Always discuss your situation with your own healthcare provider._