Duchenne Muscular Dystrophy (DMD)

A genetic disease with a devastating impact

With DMD, new activities are gained over time and then lost over time, and that’s the most heartbreaking thing.

Patricia Furlong

President and CEO of Parent Project Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a devastating diagnosis for a family to receive.¹ It is one of the most common recessive genetic disorders, affecting around 1 in every 5,000 boys born each year around the world.^2,3*

While DMD is rare, its impact is severe and life-altering for affected children and their families. Caused by a mutation in the dystrophin gene – which encodes for a critical protein that protects muscles from damage – DMD causes progressive muscle weakness throughout the body, that eventually impacts mobility, breathing and the heart.³ As the incurable disease progresses, it results in death, usually between 21 and 40 years of age.^4†

The slow erosion of strength

The early signs of DMD are typically first noticed between 16 months to 3 years of age.^3,5 Muscles that should become stronger with age begin to fail, and those with DMD typically experience a range of symptoms including:³

Developmental delay

Children with DMD often achieve milestones like standing, walking or talking later than their peers.^3,5,6

Progressive muscle weakness

Everyday activities like getting up, standing, jumping, or climbing the stairs require more effort, and children with DMD experience frequent falls until eventually they are no longer able to perform these activities at all^3,5-7

Scoliosis and muscle contractures

Muscles become shorter and very tight, which can make it harder to move. As the back muscles weaken, abnormal spinal curvature can occur. This not only causes pain but can also worsen respiratory problems and impair mobility further^3,7

Weakening of the heart and lungs

As DMD progresses, the muscles of the heart and lungs can become weaker, leading to life-threatening complications. Teens and young adults with DMD often require heart medications and ventilatory support to continue to breathe^3,7

For boys living with DMD, even the simplest moments can become battles. Patricia Furlong is the President and CEO of Parent Project Muscular Dystrophy (PPMD), a patient advocacy organisation dedicated to supporting patients with DMD and their families. Listen as she describes her personal experience as the mother of children living with DMD.

Understanding the cause of DMD

DMD is an X-linked recessive condition that is passed down through families and primarily affects males. This is because the dystrophin gene that causes DMD is located on the X chromosome^3-7:

As boys only inherit one X chromosome, if that contains the gene mutation for DMD, then the child will have the disease⁷
As girls have two X chromosomes, as long as they inherit one normal copy of the dystrophin gene, they will usually experience either no symptoms or the symptoms will be mild. These girls are carriers of DMD and can pass the defective gene on to their children^7,8

While DMD is primarily thought of as an inherited disease, it is important to note that around 30% of DMD cases are due to spontaneous mutations in the dystrophin gene and affect families with no prior history of the disease.⁹

The diagnosis of DMD typically involves a combination of family history, clinical observations, blood tests, genetic testing, and in some instances, muscle biopsy.⁵

From onset to progression

DMD is a progressive disease that follows a distinct and devastating trajectory:^3-6:

The typical life expectancy of DMD is between 21–40 years.^4† Although there is currently no cure, treatment advances may allow children who are diagnosed today to live into their fourth decade.⁵

Behind the diagnosis: The psychosocial impact of DMD

DMD doesn’t just affect patients physically, it is a life-altering diagnosis that takes a profound emotional and psychological toll on patients and their families.^1,10 DMD comes with significant neurological and cognitive implications which are likely due to dystrophin deficiency in the brain:¹⁰

24–29% experience anxiety
17–27% experience depression
3–20% have autism spectrum disorder
11–32% have attention deficit/hyperactivity disorder (ADHD)
5–11% have obsessive–compulsive disorder (OCD)

Caring for a child with DMD is also a full-time job, that is both emotionally demanding and often financially damaging:

~ 50% of caregivers experience moderate or severe levels of anxiety or depression¹¹
Up to 49% of caregivers reduce their working hours or stop working completely because of their child’s DMD¹²
Sleep deprivation, impaired health and reduced work life productivity are common¹³

Listen to Patricia Furlong, President and CEO of PPMD, discuss the tremendous impact DMD has on patients and their entire families.

Watch the full interview with Patricia Furlong here.

DMD by the numbers

~1/5,000

boys born each year globally are affected by DMD²

~30%

of DMD cases are due to spontaneous mutations and affect families with no known family history⁹

12 years

By that age, most children have lost their ability to walk^3,6

100%

with no cure, DMD is fatal in all cases³

Addressing a key unmet need for patients and their families

For families facing a DMD diagnosis, treatment options today are not curative and cannot prevent disease progression. Corticosteroids are the current standard of care, which can help slow the progression of muscle deterioration, giving children more years of mobility and independence.^3,5,14 However, they come with significant side effects including:¹⁵

Weight gain

Behavioural changes

Delayed puberty

Increased risk of fractures

Cushingoid appearance

Stunted growth

Over time, the cumulative impact of these side effects can be significant. Families need to find a balance between preserving function and managing detrimental side effects, all while watching their child’s condition worsen. As a result, there is an urgent need for safer and more effective treatment options.^5,15

At Grünenthal, we are working to improve the lives of those living with DMD—by developing a new treatment option with the potential for better efficacy than the current standard-of-care, with a lower side effect burden for patients.

Footnotes

^* Global prevalence was 19.8 cases (95% confidence interval:16.6–23.6) per 100,000 live male births.²

^† Estimated mortality for those who receive ventilatory support.⁴
References

¹ Schwartz CE, et al. Characterizing the qualityoflife impact of Duchenne muscular dystrophy on caregivers: a casecontrol investigation. J Patient Rep Outcomes. 2021 Nov 20;5:124.

² Crisafulli S, et al. Global epidemiology of Duchenne muscular dystrophy: an updated systematic review and meta-analysis. Orphanet J Rare Dis. 2020 Jun 5;15(1):141.

³ Bez Batti Angulski A, et al. Duchenne muscular dystrophy: disease mechanism and therapeutic strategies. Front Physiol. 2023 Jun 26;14:1183101.

⁴ Landfeldt E, et al. Life expectancy at birth in Duchenne muscular dystrophy: a systematic review and meta-analysis. Eur J Epidemiol. 2020 Jul;35(7):643-653.

⁵ Bushby K, et al. Diagnosis and management of Duchenne muscular dystrophy, part 1: diagnosis, and pharmacological and psychosocial management. Lancet Neurol. 2010 Jan;9(1):77-93.

⁶ Emery AEH. The muscular dystrophies. Lancet. 2002 Feb 23;359(9307):687-95.

⁷ Venugopal V, Pavlakis S. Duchenne Muscular Dystrophy. Updated July 2023. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan. Available at: https://www.ncbi.nlm.nih.gov/books/NBK482346/. Accessed September 2025.

⁸ Cleveland Clinic. Duchenne Muscular Dystrophy (DMD). Updated June 2025. Available at: https://my.clevelandclinic.org/health/diseases/23538-duchenne-muscular-dystrophy-dmd. Accessed September 2025.

⁹ Cai A and Kong X. Development of CRISPR-Mediated Systems in the Study of Duchenne Muscular Dystrophy. Hum Gene Ther Methods. 2019 Jun;30(3):71-80.

¹⁰ Tizzoni F, et al. Living with Duchenne Muscular Dystrophy Beyond the Physical Implications: Cognitive Features, Psychopathology Aspects, and Psychosocial Resources—A Narrative Review. Brain Sciences. 2025 Jun 28;15(7):695.

¹¹ Landfeldt E, et al. Quantifying the burden of caregiving in Duchenne muscular dystrophy. J hNeurol. 2016 May; 263(3):906–915.

¹² Landfeldt E, et al. The burden of Duchenne muscular dystrophy: an international, cross-sectional study. Neurology. 2014 Aug5;83(6):529–536.

¹³ Landfeldt E, et al. Duchenne muscular dystrophy and caregiver burden: a systematic review. Dev Med Child Neurol. 2018 Oct;60(10):987-996.

¹⁴ McDonald CM, et al. Long-term effects of glucocorticoids on function, quality of life, and survival in patients with Duchenne muscular dystrophy: a prospective cohort study. Lancet. 2018 Feb 3;391(10119):451-461.

¹⁵ Fischer R, et al. A Mixed-Method Study Exploring Patient-Experienced and Caregiver-Reported Benefits and Side Effects of Corticosteroid Use in Duchenne Muscular Dystrophy. J Neuromuscul Dis. 2023;10(4):593-613.

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