Duchenne Muscular Dystrophy Diagnosis: How to Identify DMD
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Duchenne Muscular Dystrophy (DMD) Diagnosis

Duchenne Muscular Dystrophy (DMD) Diagnosis
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Published on October 17, 2024
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Duchenne muscular dystrophy (DMD) is one of the most severe forms of inherited muscular dystrophy.

This rare genetic disorder is due to the absence of a vital protein called dystrophin that helps the body maintain muscle cells, which results in rapid muscle degeneration and increasing muscle weakness. Symptoms begin in childhood, with patients eventually requiring a wheelchair and/or a breathing device.

Although there’s no cure for DMD, early diagnosis can help ensure timely access to treatment, counseling, and screening for complications, slowing disease progression and improving quality of life.

Here is an overview of how a Duchenne muscular dystrophy diagnosis works.

DMD Symptoms

DMD symptoms in a child may send a parent or caregiver to the doctor, or prompt a doctor to send a child to a specialist for a confirmed diagnosis.

Typically boys are affected by DMD rather than girls, and they often experience the first symptoms between the ages of 2 and 5. These may include:

  • Using hands to get up from sitting or squatting, a movement called Gower’s sign

  • Trouble with running, jumping, and climbing stairs
  • Enlarged calves, also known as pseudohypertrophy (“false enlargement”) because the muscles look bigger even though they are weaker

  • Waddling
  • Leg pain
  • Difficulty climbing stairs
  • Short stature
  • Learning problems, which can happen as the disease disrupts brain activity that is essential for memory formation and consolidation.

As the condition progress, children may experience:

  • Broken bones from falling
  • Greater need for a wheelchair
  • Curving of the spine (scoliosis)
  • Stiff joints that can’t move (contractures)
  • Tiredness (fatigue) and weakness
  • Shortness of breath or other breathing problems due to weakening of the diaphragm
  • Irregular heartbeat or other heart problems

Diagnostic Medical Exam for Duchenne

While the symptoms observed by parents or other adults provide clues that a child has Duchenne, an accurate diagnosis requires a physical examination from a doctor, as well as testing.

Because Duchenne muscular dystrophy is inherited, healthcare practitioners will ask detailed questions about the patient’s family health history — specifically if anyone in the family is known to have had DMD, any other type of muscular dystrophy, or any kind of neuromuscular disease.

The physician will check whether the parents have noticed any of the telltale symptoms, and also perform their own assessment.

By having a patient complete a short walking test, move from a lying down position to a standing one, and climb up and down a few stairs, a medical professional may observe symptoms and establish the level of muscle performance and disease progression.

Exercises that test strength or weakness in specific muscles in upper and lower limbs may be part of a physical evaluation.

Electrodiagnostic tests (EMG/NCS) may be included in a diagnostic workup. These use a machine that measures electrical signals in muscles and nerves to assess how they are functioning.

DMD Diagnostic Lab Tests

After evaluating symptoms that may suggest Duchenne, physicians will typically turn to lab tests that can confirm the diagnosis:

Creatine Kinase (or CK Level) Blood Test Doctors take a blood sample to measure levels of creatine kinase, an enzyme that leaks out of damaged muscle. Elevated CK levels usually means that muscle is being disintegrated by some abnormal process, such as muscular dystrophy.

Genetic Testing A lab analysis of the DNA (the molecule that contains genetic information) in a blood or saliva sample can reveal whether there are genetic mutations that prevent muscles from producing the protein dystrophin. If the test comes back with the terms “Positive result,” “Mutation detected,” “Pathogenic variant detected,” or similar, it is confirmation of a DMD gene mutation.

Muscle Biopsy By taking a minute tissue sample from the thigh or calf, doctors can look at the cells under a microscope and get a clearer picture of what is happening inside the muscle. Specialists look for endomysial connective tissue proliferation — a type of abnormal tissue growth in patients with DMD that is apparent long before any muscle degeneration can be observed.

They also will note any general degeneration, abnormal cell death of muscle cells (necrosis), regeneration of myofibers (cells that make up skeletal muscle and rise with muscle injury), and replacement of muscle with adipose tissue and fat.

A biopsy involves injecting a numbing medicine, such as lidocaine, into the skin and muscle at the biopsy site, to reduce pain. The biopsy site may be tender for two to three days after the procedure.

Electrocardiogram (EKG) and Echocardiogram (Echo) DMD almost always affects the heart, and an EKG to check heartbeat and electrical signals can reveal characteristic symptoms of the disease. Abnormal rhythms suggest heart muscle damage.

While an EKG provides details about the heart’s electrical activity, a doctor may want to look more closely at the structure of the heart using an echocardiogram, which uses high-frequency sound waves (ultrasound) to make pictures of the organ. Studies have shown improvement in the early diagnosis of DMD-related cardiomyopathy with advanced echocardiogram techniques.

With DMD, cardiac function worsens, and heart failure can develop. Based on EKG and echocardiogram readings, doctors may prescribe medications that help heart function.

DMD Screening Tests for Babies

A few states (such as Ohio, Minnesota, New York, and Massachusetts) now mandate genetic testing for Duchenne muscular dystrophy in all newborns as part of a standard array of blood tests. Other states may follow suit.

Parents interested in genetic testing for their newborn may also want to check out Parent Project Muscular Dystrophy’s genetic testing program, Decode Duchenne, which provides free genetic testing to eligible individuals.

Doctors That Can Diagnose DMD

Primary care physicians and pediatricians are often the first healthcare professionals to identify signs of Duchenne.

A consultation with an expert, such as a pediatric neurologist or neuromuscular specialist, is likely needed to confirm a Duchenne muscular dystrophy diagnosis.

Specialists who have years of experience with DMD can more readily recognize its symptoms and guide patients toward treatments, such as corticosteroids, which can decrease the rate of declining strength.

They can also direct patients to physical and occupational rehabilitation professionals who can teach children strengthening exercise programs and activities, orthopedic surgeons who may treat severe tightening of the muscles (contractures) and scoliosis (curvature of the spine), pediatric cardiologists who can evaluate heart function, and mental health specialists who can assist with the emotional strains of this illness.


The Takeaway

  • Symptoms of Duchenne muscular dystrophy often appear at a young age, and recognizing these signs is the first step in diagnosing DMD.
  • A detailed physical exam by a doctor, along with a series of lab tests, will help confirm whether a patient has DMD.
  • Genetic testing soon after birth is becoming more widespread as public health officials recognize that early detection and treatment can slow patients’ disease progression and improve their quality of life.

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Anna-Hurst-bio

Anna C.E. Hurst, MD, MS, FACMG

Medical Reviewer
Castle Connolly Top Doctor
Anna C. E. Hurst, MD, is a medical geneticist with board certification in clinical genetics and pediatrics. She is an associate professor in the department of genetics at University of Alabama at Birmingham (UAB) and an adjunct faculty member at the HudsonAlpha Institute for Biotechnology. Prior to medical school, she received a master’s degree in genetic counseling, which inspired her interest in the communication of genetic information to patients and families with rare diseases.

Dr. Hurst is a physician for the UAB Undiagnosed Disease program, Turner syndrome clinic, and general genetics clinic, and she provides hospital consultations for inpatients at UAB and Children’s of Alabama for general genetics and inborn errors of metabolism. She also is the medical geneticist for the Smith Family Clinic for Genomic Medicine in Huntsville, Alabama.

Hurst's research focuses on expanding the availability of genomic sequencing for children with complex healthcare needs. She also has an interest in how the patient’s physical exam and facial features can be clues to a rare disease diagnosis (dysmorphology) and serves on the scientific advisory board of Facial Dysmorphology Novel Analysis. She has published over 45 peer-reviewed articles in the field of medical genetics, largely focused on the clinical delineation of rare disease phenotypes. She also serves as an associate editor for the American Journal of Medical Genetics.

Hurst is also passionate about education and serves as the program director of the UAB genetics residency programs (categorical, pediatrics-genetics, and internal medicine-genetics) and medical director of the UAB Genetic Counseling Training program. She is an officer with the Association of Professors in Human Medical Genetics.
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Don Rauf

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Don Rauf has been a freelance health writer for over 12 years and his writing has been featured in HealthDay, CBS News, WebMD, U.S. News & World Report, Mental Floss, United Press International (UPI), Health, and MedicineNet. He was previously a reporter for DailyRx.com where he covered stories related to cardiology, diabetes, lung cancer, prostate cancer, erectile dysfunction, menopause, and allergies. He has interviewed doctors and pharmaceutical representatives in the U.S. and abroad.

He is a prolific writer and has written more than 50 books, including Lost America: Vanished Civilizations, Abandoned Towns, and Roadside Attractions. Rauf lives in Seattle, Washington.

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Resources
  1. Venugopal V et al. Duchenne Muscular Dystrophy. StatPearls. July 10, 2023.
  2. About Duchenne. Duchenne.com.
  3. Duchenne Muscular Dystrophy (DMD). Muscular Dystrophy Association.
  4. Duchenne Muscular Dystrophy in Children. Cedars Sinai.
  5. Duchenne Muscular Dystrophy. National Organization for Rare Disorders. July 15, 2024.
  6. Walters J. Muscle Hypertrophy and Pseudohypertrophy. Practical Neurology. October 2017.
  7. Duchenne Muscular Dystrophy (DMD) Diagnosis. Muscular Dystrophy Association.
  8. Duchenne Muscular Dystrophy. Cleveland Clinic. July 25, 2022.
  9. Witherspoon J et al. Two-Minute Versus 6-Minute Walk Distances During 6-Minute Walk Test in Neuromuscular Disease: Is the 2-Minute Walk Test an Effective Alternative to a 6-Minute Walk Test. European Journal of Paediatric Neurology. January 2019.
  10. Lerario A et al. Quantitative Muscle Strength Assessment in Duchenne Muscular Dystrophy: Longitudinal Study and Correlation With Functional Measures. BMC Neurology. September 13, 2012.
  11. Duchenne Muscular Dystrophy Diagnosis. Stanford Medicine.
  12. Is It Duchenne? Diagnosis. Parent Project Muscular Dystrophy.
  13. Duan D et al. Duchenne Muscular Dystrophy. Nature Reviews Disease Primers. February 18, 2021.
  14. Klingler W et al. The Role of Fibrosis in Duchenne Muscular Dystrophy. Acta Myologica. December 2012.
  15. Pizza FX et al. Regenerating Myofibers After an Acute Muscle Injury: What Do We Really Know About Them? International Journal of Molecular Sciences. August 2023.
  16. Muscle Biopsy. UTHealth Houston/McGovern School of Medicine.
  17. Prakash N et al. Cardiac MRI and Echocardiography for Early Diagnosis of Cardiomyopathy Among Boys With Duchenne Muscular Dystrophy: A Cross-Sectional Study. Frontiers in Pediatrics. March 14, 2022.
  18. Feingold B et al. Management of Cardiac Involvement Associated With Neuromuscular Diseases: A Scientific Statement From the American Heart Association. Circulation. August 24, 2017.
  19. Duchenne Muscular Dystrophy (DMD) Added to Minnesota’s Newborn Screening Panel. Minnesota Department of Health. January 26, 2024.
  20. Muscular Dystrophy Added to New York State’s Newborn Screening Panel. Parent Project Muscular Dystrophy. October 25, 2023.
  21. Duchenne Muscular Dystrophy Added to Massachusetts’ Newborn Screening Panel. Parent Project Muscular Dystrophy. August 27, 2024.
  22. Birnkrant DJ et al. Diagnosis and Management of Duchenne Muscular Dystrophy, Part 3: Primary Care, Emergency Management, Psychosocial Care, and Transitions of Care Across the Lifespan. The Lancet Neurology. May 2018.
  23. Duchenne Muscular Dystrophy. Johns Hopkins Medicine.