What is DMD (Duchenne Muscular Dystrophy)? Symptoms and Treatment

The question of "what is DMD" is frequently researched by parents who notice delayed motor development in their children, especially during early childhood. Duchenne Muscular Dystrophy (DMD) is a progressive muscle weakness condition caused by a deficiency of a protein called dystrophin, which protects muscle integrity in the body. Primarily affecting boys, this condition can be managed with early diagnosis and a multidisciplinary approach, leading to a significant increase in the patient's independent mobility and quality of life.

• In brief:
• DMD is caused by a genetic mutation on the X chromosome and is predominantly seen in boys.
• The first symptoms usually appear between the ages of 2 and 3, starting with frequent falls, delayed walking, and difficulty climbing stairs.
• A false enlargement (pseudohypertrophy) in the calf muscles is noticeable, as muscle tissue is replaced by fat tissue.
• High levels of Creatine Kinase (CK) in the blood and genetic testing play a decisive role in the diagnostic process.
• While there is no definitive cure, corticosteroid medications and physical therapy help slow the progression of the disease.

What is DMD?

Duchenne Muscular Dystrophy, commonly known as muscle wasting, is one of the most common and severe genetic muscle diseases encountered in childhood. The human body contains a protein called dystrophin, which acts almost like a shock absorber, preventing muscle fibers from being damaged during contraction and relaxation. In children with DMD, a genetic error means this protein is either not produced at all or remains dysfunctional.

In the absence of dystrophin, muscle fibers are continuously damaged during daily movements. Although the body initially tries to repair this damage, over time, muscle tissue begins to be replaced by fat and connective tissue. This leads to the muscles gradually weakening and losing their function. The disease usually starts in the large muscle groups close to the center of the body (proximal), such as the legs and hips, and spreads to the arms, respiratory muscles, and heart muscle in later years. Affecting approximately one in every 3,500 to 5,000 boys, early detection and the initiation of supportive treatments can extend the time these children can walk independently.

Causes and Risk Factors of Duchenne Muscular Dystrophy

The root cause of the disease is mutations in the gene responsible for producing the dystrophin protein. This gene is located on the X chromosome, one of the sex-determining chromosomes. While females have two X chromosomes, males have one X and one Y chromosome. Even if mothers carry the faulty gene, they usually do not show symptoms of the disease thanks to their other healthy X chromosome; they merely act as carriers. However, boys who inherit this faulty X chromosome experience the disease directly because they do not have a second X chromosome to compensate. Due to this genetic inheritance pattern, the condition is known almost entirely as a boys' disease.

In about two-thirds of cases, the mutation is passed from a carrier mother to her child, while in the remaining one-third, there is no family history of the disease. This is called a de novo (new) mutation; the genetic error occurs spontaneously during development in the womb. Those with a family history of muscle disease or unexplained motor developmental delay form the highest risk group. The daughters of carrier mothers also have a 50 percent chance of being carriers. Therefore, when a diagnosis is made within a family, seeking genetic counseling and screening other family members is of great importance.

DMD Symptoms: How to Spot Muscle Wasting in Children

DMD symptoms manifest in different ways parallel to a child's growth stages. During infancy, no obvious problems are usually observed, though some babies may experience slight delays in milestones like holding their head up or sitting. The most noticeable signs begin at the walking age. Children failing to walk independently by 18 months or tending to walk on their toes are among the first red flags. Such motor delays can be detected during routine doctor visits; therefore, keeping up with the childhood vaccination schedule and regular well-child check-ups is a critical step for early diagnosis.

By the time they reach three to five years of age, the symptoms become much more pronounced. Children struggle to run, jump, and climb stairs compared to their peers. Frequent falling and difficulty getting up from the floor are the most typical complaints. During this period, a characteristic movement called Gowers' sign is observed: to get up from the floor, the child first puts their hands on the ground, then walks their hands up their own legs, essentially climbing up their own body to stand straight. Additionally, a false swelling (pseudohypertrophy) is noticed in the calf muscles, making them look overly developed from the outside because the muscle has wasted away and filled with fat tissue. In later years, as the shoulder and arm muscles are also affected, lifting the arms becomes difficult.

The Diagnostic Process at the Hospital

The diagnostic process begins when parents notice differences in motor development and consult a physician. A pediatric neurologist performs a detailed physical examination to evaluate the child's muscle strength, reflexes, and walking pattern. In suspected cases, the first requested test is measuring the Creatine Kinase (CK) level in the blood. CK is an enzyme normally found inside muscle cells. When muscle fibers are damaged, this enzyme leaks into the bloodstream. While the CK level in a healthy child is usually below 200 U/L, in children with DMD, this value can reach into the tens of thousands.

Although a high CK value in a blood test proves muscle breakdown, a definitive diagnosis is made through genetic testing. Genetic analysis from a blood sample can detect deletions, duplications, or point mutations in the dystrophin gene. Genetic testing not only confirms the diagnosis but also identifies the exact genetic error, guiding potential future treatments. More invasive tests frequently used in the past, such as muscle biopsies or EMG (electromyography), are now rarely needed thanks to advanced genetic analysis methods.

DMD Treatment and Care Process

There is currently no definitive cure that completely eradicates the disease. However, thanks to advances in medical approaches, the duration of children's independent walking is extended, and their quality of life is significantly improved. Corticosteroid medications form the cornerstone of treatment. Started under a doctor's supervision, these drugs slow down muscle breakdown, preserve muscle strength, and help respiratory and heart functions remain healthy for longer. The dosage and duration of the medication are meticulously adjusted by a pediatric neurologist based on the child's weight, age, and side-effect profile.

Alongside medical treatment, physical therapy and rehabilitation are integral parts of the care process. Regular, gentle stretching exercises prevent stiffness (contractures) that can develop in the joints. Using special splints (orthoses) at night is recommended to prevent the shortening of areas like the Achilles tendon. Heavy weightlifting or exercises that overly fatigue the muscles should be avoided, as they can accelerate muscle breakdown. The treatment process is not limited to neurology; it requires a multidisciplinary approach where cardiology, pulmonology, orthopedics, and nutrition experts work together.

Complications and Risk Groups

In the later stages of the disease, muscle weakness affects the body's other vital systems, paving the way for various complications. The weakening of the heart muscle can lead to an enlarged heart, known as cardiomyopathy, and rhythm disturbances. Because this condition often develops silently starting from the early teenage years, it is essential for patients to be regularly monitored with echocardiography (ECHO). Deterioration in heart function can be controlled with early-initiated cardiological medications.

Another significant complication is the involvement of the respiratory muscles. The weakening of the diaphragm and intercostal muscles reduces the cough reflex and prevents the lungs from working at full capacity. Because the airways cannot be cleared, common winter illnesses in children and simple colds can turn into severe conditions like pneumonia in these patients. Furthermore, with the weakening of the back muscles and the transition to wheelchair use, the risk of developing spinal curvature (scoliosis) is quite high. Bone thinning (osteoporosis) due to steroid use and immobility is also among the frequently encountered problems.

When to See a Doctor?

If you notice a delay in your child's motor development compared to their peers, you should consult a pediatrician or a pediatric neurologist without delay. You should take the situation seriously, especially if one or more of the following symptoms are present:

• If your child is 18 months old but still cannot walk independently,
• If they consistently tend to walk on their toes after starting to walk,
• If they cannot run or jump by the time they are two and a half years old,
• If they need to support themselves with their hands on their knees when getting up from the floor,
• If they frequently stumble and fall, and have difficulty climbing stairs.

For patients who have been diagnosed and are being monitored, sudden onset of shortness of breath, chest pain, palpitations, extreme fatigue, bluish lips, or confusion require immediate medical attention. If you suspect a respiratory tract infection or feel an abnormality in the heart rhythm, you should immediately call 112 for emergency services or go to the emergency department of the nearest fully equipped hospital.

The Process at BHT CLINIC

In the management of muscle diseases that require complex and long-term follow-up, an experienced healthcare team and a fully equipped infrastructure are of great importance. In our Pediatric Neurology department, we stand by you at every stage from diagnosis to treatment with our expert physicians and multidisciplinary approach. At our hospital, all examinations, from genetic tests to cardiological evaluations and pulmonary function tests, are performed under one roof in a child-friendly environment.

In cases of unexpected respiratory distress or infections, we offer a safe intervention environment with our 24/7 emergency service and advanced pediatric intensive care unit. To plan your child's routine follow-ups, address your concerns about developmental delays, or get a second opinion, you can reach us through our call center at 0850 811 34 00. If you wish, you can easily complete your procedures via our appointment page and take the best step for your child's health.

Frequently Asked Questions

Is DMD seen in girls?

Because the disease is transmitted recessively via the X chromosome, the probability of it occurring in girls is extremely low. Even if girls carry the faulty gene, they usually do not show symptoms thanks to their other healthy X chromosome and merely act as carriers. In very rare genetic abnormalities, mild symptoms can also appear in girls.

What is the life expectancy for DMD patients?

While patients were often lost in their early twenties in past decades, this period has been significantly extended thanks to advances in medical care, respiratory devices, and cardiological treatments. With good, multidisciplinary care, patients can live into their thirties and forties.

What is Gowers' sign?

Gowers' sign is a typical maneuver a child performs when getting up from the floor to compensate for weakness in the pelvic and upper leg muscles. To stand up, the child places their hands on the ground, then grasps their own knees and thighs with their hands, pushing their body upward.

Can a DMD test be done in the womb?

Yes, if there is a known mutation in the family, prenatal diagnostic methods can be applied during pregnancy. Through procedures like chorionic villus sampling (CVS) or amniocentesis, the genetic structure of the baby in the womb can be examined to detect the presence of the disease.

What tests are performed on a child suspected of having DMD?

Following a physical examination, the first step is to check the level of the Creatine Kinase (CK) enzyme in the blood, which indicates muscle breakdown. If the CK value is very high, genetic blood tests (DNA analysis) are performed to make a definitive diagnosis and determine the type of mutation.

This article is for informational purposes only; please be sure to consult your physician for diagnosis and treatment.