When you have a baby, you may look forward to watching them sit up on their own or happily await the first time they roll over. Those moments can be exciting for any parent. But if your child struggles or misses those developmental milestones, you could start to worry. If their delay is significant, your pediatrician may talk with you about muscular dystrophy (MD).

Muscular dystrophy is a group of neuromuscular genetic conditions that affect the skeletal muscles. These muscles connect your bones and control your movements. For people with muscular dystrophy, skeletal muscles break down and weaken over time.

Thankfully, recent research has produced treatments that help slow disease progression or reduce the impact of symptoms. These therapies work best when people start before they develop permanent muscle damage. That means early diagnosis — in infancy, if possible — is critical.

Learn more about how muscular dystrophy appears in babies and the early signs you should discuss with your pediatrician.

Early Muscular Dystrophy Signs in Babies

Many symptoms of MD appear in later childhood and into the teen years or 20s. However, several signs show up during infancy. Recognizing these signs quickly is vital. Early detection can lead to better, more effective treatments.

Keep reading to learn about the early signs of muscular dystrophy in infants.

1. Delayed Motor Milestones

Missing or reaching a motor milestone late may be a sign of MD. These developmental delays can show up as early as two or three months after birth. They occur most often in male infants with Duchenne muscular dystrophy (DMD). DMD is the most common childhood form of muscular dystrophy.

People with Duchenne and Becker muscular dystrophy (BMD) have a genetic mutation (variation) in the dystrophin gene. This gene produces the protein dystrophin that protects your muscles and helps them work well. Babies with Duchenne often have difficulty holding up their head and sitting up without help. They may start crawling or standing later than typical. Many do not start walking until after 18 months.

2. Low Muscle Tone and Muscle Weakness

According to the Muscular Dystrophy Association, muscle weakness is one of the first signs that an infant may have muscular dystrophy. In some cases, babies — especially those with congenital muscular dystrophy (CMD) — may also have hypotonia (low muscle tone) and feel “floppy” when held. However, in Duchenne muscular dystrophy, muscle weakness is typically more prominent than hypotonia.

In DMD, muscle weakness begins early, worsens over time, and follows a predictable pattern. It starts in the hips, pelvis, and shoulders before progressing to the thighs, lower arms, abdomen (stomach area), and back. As a result, children with Duchenne often struggle to stand up from the floor, a difficulty known as Gowers’ sign.

As children grow, muscle weakness makes crawling, walking, and climbing stairs increasingly difficult. According to Cedars-Sinai, most boys with Duchenne lose the ability to walk and require a wheelchair by the time they’re teens

3. Muscle Stiffness

While some babies with muscular dystrophy have hypotonia, others experience muscle stiffness, known as myotonia. This occurs most often in myotonic dystrophy and makes it difficult for babies to relax their muscles after contracting them. For example, they may struggle to release a caregiver’s finger after gripping it with their fist.

In contrast, DMD and Emery-Dreifuss muscular dystrophy can lead to muscle contractures — a different type of muscle stiffness that affects movement over time. Contractures develop when stiff, inflexible scar tissue replaces normal tendons, which connect muscles to bones. As a result, joints become stuck in certain positions, most often in flexion (bent positions). However, in some cases, contractures can also occur in extension (straightened positions), depending on the specific muscles affected.

4. Breathing and Swallowing Problems

Difficulty breathing or swallowing may be additional signs of muscular dystrophy in babies. Low muscle tone and weakness can affect the chest and diaphragm. As a result, they may have a weak cry or cough. Your baby may wheeze, and you may notice they have a harder time breathing while sleeping.

Breathing deeply may be difficult for babies with MD. So, they may take fast, shallow breaths. However, not all babies with muscular dystrophy have shortness of breath. Some children are sleepy much of the time and have trouble staying awake.

Babies with myotonic dystrophy frequently have trouble swallowing. Weak muscles in their mouth and throat make the process difficult. They are more likely to choke and develop lung infections like pneumonia.

Early Detection and Diagnosis Matter

Muscular dystrophy is a progressive condition that leads to irreparable muscle damage. Muscle weakness gets worse over time for every person with MD. Eventually, many people with the condition lose the ability to walk. However, several muscular dystrophy treatments are most effective before irreversible muscle damage happens. That’s why timely detection matters.

Duchenne diagnosis in most male children occurs between ages 4 and 5, according to research in Frontiers in Pediatrics — several years after symptoms first appear. Recognizing the early symptoms is vital. But, other diagnostic tools like genetic testing, muscle biopsies, and physical assessments are valuable methods for early identification.

Genetic Testing

Muscular dystrophy is a genetic condition. One study revealed that:

• Around 60 percent to 70 percent of DMD cases are caused by deletions — A section of the dystrophin gene is missing, disrupting the production of dystrophin.
• Between 5 percent and 15 percent are caused by duplications — An extra copy of part of the gene is present, which interferes with the gene’s ability to produce dystrophin.
• Around 20 percent are caused by point mutations (small insertions/deletions) — These small changes can prevent the dystrophin gene from being correctly read, which stops the production of dystrophin.

Genetic testing, particularly next-generation sequencing (NGS), has made diagnosing these mutations faster and more precise.

Genetic testing for your child offers three benefits. These tests can:

• Confirm their diagnosis and what type of MD they have
• Help you decide if you want to test your existing or future children for MD
• Identify therapies that specifically target and treat their type of MD

Muscle Biopsy

According to Johns Hopkins Medicine, muscle biopsy is one of the first tests doctors may recommend when someone experiences muscle weakness. It helps detect the level of dystrophin protein in muscle cells, making it an important tool for diagnosing DMD or BMD.

The procedure is relatively quick and simple. A healthcare provider removes a small tissue sample using a thin biopsy needle or a small surgical incision. The sample is typically taken from one side of the body, with the muscle chosen based on the degree of weakness and disease progression. Common biopsy sites include the biceps brachii (upper arm), deltoid (shoulder), or quadriceps (thigh muscle). The sample is then examined under a microscope to determine the level of dystrophin protein and assess muscle damage.

Physical Assessment

In addition to genetic testing and muscle biopsy, your child’s doctor may suggest several other physical tests to diagnose MD, according to NYU Langone Health, an academic medical center in New York City. Each test reveals more details about your child’s health, potentially leading to a faster, more accurate diagnosis.

These tests include:

• Blood test — This test looks for high levels of creatine kinase. The body releases high levels of this enzyme when muscle fibers break down.
• Electromyography — This test measures how well muscles respond to electrical impulses. Muscles don’t respond well in people who have muscular dystrophy.
• Nerve conduction study — This test determines how fast an electrical impulse travels through a nerve. People with muscular dystrophy have slower electrical responses in their muscles.

Identifying Muscular Dystrophy in Your Child

Talk with your child’s pediatrician if you notice any early signs of muscular dystrophy. They can recommend diagnostic tests and possible treatments to improve their symptoms and well-being.

Talk With Others Who Understand

On myMDteam, the social network for people with muscular dystrophy and their loved ones, members ask questions, give advice, and share their stories with others who understand life with MD.

Did your child experience any early signs of muscular dystrophy, such as delayed milestones, muscle weakness, or breathing difficulties? How did you navigate the diagnostic process? Share your experience in the comments below, start a conversation by posting on your Activities page, or connect with like-minded members in Groups.