OVERVIEW

What is Duchenne Muscular Dystrophy?

Duchenne Muscular Dystrophy is a rare inherited degenerative muscle disease, primarily characterized by slow, progressive, and symmetrical muscle weakness and atrophy. It is a relatively common type of progressive muscular dystrophy, with an incidence rate of approximately 30 per 100,000 male infants.
Duchenne Muscular Dystrophy follows an X-linked recessive inheritance pattern, meaning only males are affected.
Most cases of Duchenne Muscular Dystrophy begin between ages 2-3, with patients typically passing away in their teens or twenties, and there is currently no cure. Some research reports indicate an average lifespan of 35 years for patients.

SYMPTOMS

What are the manifestations of Duchenne muscular dystrophy?

Symptoms of Duchenne muscular dystrophy typically begin to appear between the ages of 2 and 3:

• Pseudohypertrophy of muscles: One of the earliest symptoms of Duchenne muscular dystrophy is "pseudohypertrophy," where muscle fibers atrophy and are replaced by fat and connective tissue. The affected muscles may appear enlarged and firm to the touch, but their strength is actually weakened, making patients feel weak. The most noticeable area of pseudohypertrophy is the calf muscles (gastrocnemius), though it can also occur in other muscles.

• Muscle weakness: Children initially experience muscle weakness in the trunk, which gradually spreads to the limbs, hands, and feet. For example, weakness in the pelvic muscles may cause slow walking, frequent falls, and difficulty climbing stairs or squatting. Weakness in the abdominal, lower back, and thigh muscles can lead to "Gowers' sign," where the child cannot sit up directly from lying down and must first roll onto their stomach, push up onto their hands and knees, and then use their hands to slowly stand. This is a characteristic feature of Duchenne muscular dystrophy. Weakness in the shoulders and arms is usually milder, but lifting the arms may reveal prominent shoulder blades.

• As symptoms worsen, patients develop significant Achilles tendon contractures, foot drop, and difficulty walking. Most children lose the ability to walk by around age 12 and require a wheelchair. Subsequently, muscles throughout the body atrophy severely, including the respiratory muscles, leading to weak breathing and coughing, impaired heart function, and eventual death.

CAUSES

What is the cause of Duchenne muscular dystrophy?

Duchenne muscular dystrophy is caused by a genetic defect located on the X chromosome. Parents pass the defective gene to their children, leading to the disease in male offspring.

How is Duchenne muscular dystrophy inherited?

Duchenne muscular dystrophy follows an X-linked recessive inheritance pattern with the following characteristics:

• Affected males do not pass the disease to their sons;

• Affected males do not pass the disease to their daughters, but daughters will carry the defective gene;

• Sons born to female carriers have a 50% chance of inheriting the disease.

Is Duchenne muscular dystrophy contagious?

No.

DIAGNOSIS

How is Duchenne muscular dystrophy diagnosed?

Doctors make a comprehensive diagnosis based on the patient's clinical manifestations, inheritance pattern, age of onset, family history, as well as electromyography, muscle biopsy, serum tests, and genetic analysis.

What tests are needed to confirm a diagnosis of Duchenne muscular dystrophy?

• Serum enzyme tests: A blood test to measure levels of muscle-related enzymes such as creatine kinase, lactate dehydrogenase, and creatine kinase isoenzymes. In Duchenne muscular dystrophy, these enzymes are significantly elevated (12–100 times the normal range).

• Electromyography (EMG): Electrodes are placed on the muscles, or needle electrodes may be inserted to assess muscle response. Needle electrodes may cause a stinging sensation similar to an injection.

• Muscle biopsy: A minor surgical or invasive procedure is performed to extract a small muscle tissue sample for laboratory analysis. This checks for muscle tissue necrosis, regeneration, and the presence of specific proteins in muscle cells.

• Genetic testing: Directly detects gene mutations in the patient. This test is relatively expensive and time-consuming.

• Other tests: X-rays, electrocardiograms (ECG), and echocardiograms assess heart involvement. CT or MRI scans determine the extent and severity of muscle damage. Since patients may have cognitive impairments, intelligence testing is also required.

TREATMENT

Which department should I visit for Duchenne muscular dystrophy?

Neurology.

Is it necessary to go to the hospital for Duchenne muscular dystrophy?

Yes. Hospital visits are required for accurate diagnosis, condition assessment, and treatment planning.

How is Duchenne muscular dystrophy treated?

Currently, corticosteroids (such as prednisone) are the primary drugs for treating Duchenne muscular dystrophy, but they can only increase muscle strength and slow disease progression, not cure the condition.
When using this treatment, side effects of corticosteroids must be monitored, such as peptic ulcers and bleeding, elevated blood sugar, high blood pressure, osteoporosis, and low potassium levels.

Can Duchenne muscular dystrophy be cured?

No. Patients typically die in their teens or twenties, though some studies report an average lifespan of 35 years.

DIET & LIFESTYLE

What should patients with Duchenne muscular dystrophy pay attention to in their diet?

There are no specific dietary restrictions, but a balanced diet is important. Protein-rich foods such as eggs, meat, and dairy products can be appropriately increased.

What should patients with Duchenne muscular dystrophy pay attention to in daily life?

Muscles weaken with disuse, so moderate exercise is essential. Avoid prolonged bed rest and engage in daily activities as much as possible.

Does Duchenne muscular dystrophy affect fertility?

No. However, prenatal genetic diagnosis is recommended. If the fetus is diagnosed with the condition, termination of pregnancy should be considered to prevent the birth of an affected child.

PREVENTION

Can Duchenne muscular dystrophy be prevented? How to prevent it?

The best prevention method is prenatal genetic diagnosis. Individuals with a family history of Duchenne muscular dystrophy should undergo prenatal genetic testing. If an affected fetus is detected, the pregnancy should be terminated to prevent the birth of an affected child.