Duchenne Muscular Dystrophy (DMD): An Overview

Definition

Duchenne Muscular Dystrophy (DMD) is a rare, inherited neuromuscular disorder that predominantly affects boys. It is caused by a mutation in the dystrophin gene, resulting in the absence of dystrophin, a protein essential for maintaining muscle fiber integrity. Clinical symptoms typically appear between 2 and 5 years of age and progress over time.

 Epidemiology:

DMD is an X-linked condition occurring almost exclusively in males. The global prevalence is approximately 7 per 100,000 males, with a birth prevalence of about 1 in 5,000 live male births. Despite being classified as a rare disease, DMD is the most common and severe form of childhood muscular dystrophy worldwide. Variations in prevalence across regions may be influenced by genetic factors, diagnostic practices, and consanguinity rates.

 Causes and Pathophysiology

DMD results from the inability of muscle cells to produce adequate dystrophin. Dystrophin protects muscle fibers from mechanical stress during normal movement. In its absence, muscle fibers become fragile and prone to damage, leading to progressive muscle degeneration. Over time, muscle tissue is replaced by fat and connective tissue, causing worsening weakness and functional decline.

As the disease progresses, involvement extends to:

• . Respiratory muscles, leading to reduced ventilatory capacity
• . Cardiac muscle, increasing the risk of cardiomyopathy

These complications necessitate regular multidisciplinary monitoring.

 Clinical Presentation

Typical clinical features include:

• . Delayed motor milestones (walking after 18 months)
• . Progressive proximal muscle weakness (pelvic girdle > shoulder girdle)
• . Difficulty with running, jumping, stair climbing, and rising from the floor
• . Positive Gowers’ sign
• • . Waddling gait and toe walking
  • . Calf pseudohypertrophy
  • . Frequent falls and reduced endurance

  Advanced stages may involve loss of ambulation, scoliosis, cardiomyopathy, respiratory muscle weakness, and mild cognitive impairment.

   

  Diagnosis

  Diagnosis is based on clinical assessment and confirmed through investigations:

  • . Detailed history and physical examination
  • . Markedly elevated serum creatine kinase (CK) levels
  • . Genetic testing to identify mutations in the DMD gene (gold standard)
  • . Muscle biopsy when genetic testing is inconclusive
  • . Ongoing cardiac and pulmonary evaluations to monitor disease progression

  
  

• Role of Physiotherapy

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• Physiotherapy is a core component of DMD management, aiming to preserve function, delay complications, and improve quality of life.

  Physiotherapy interventions focus on:

  • . Maintaining joint range of motion and preventing contractures
  • . Supporting functional mobility and participation
  • . Preserving respiratory function through targeted exercises
  • . Monitoring posture and spinal alignment
  • . Managing pain and optimizing comfort
  • . Educating families on orthoses, assistive devices, and home programs

  While DMD remains a progressive condition, physiotherapy contributes significantly to prolonging independence and functional participation

   Our Approach at The One Physiotherapy Center

  At The One Physiotherapy Center, we provide comprehensive assessment and early intervention for children with neuromuscular disorders such as Duchenne Muscular Dystrophy. Our specialized team delivers individualized, evidence-based treatment programs focused on maintaining mobility, optimizing function, and enhancing quality of life. We emphasize early intervention, family education, and continuous follow-up to support both the child and the family throughout the care journey.

   

  References

  Chang, M., Cai, Y., Gao, Z., et al. (2023). Duchenne muscular dystrophy: Pathogenesis and promising therapies. Journal of Neurology, 270(8), 3733–3749.

  Morales, A., & Mahajan, K. (2023). Dystrophinopathies. Stat Pearls Publishing.

  Crisafulli, S., Sultana, J., Fontana, A., et al. (2020). Global epidemiology of Duchenne muscular dystrophy: An updated systematic review and meta-analysis. Orpha net Journal of Rare Diseases, 15(1), 141.

  Ryder, S., Leadley, R. M., Armstrong, N., et al. (2017). The burden, epidemiology, costs and treatment for Duchenne muscular dystrophy. Orpha net Journal of Rare Diseases, 12(1), 79.

  Bushby, K., Finkel, R., Birn Krant, D. J., et al. (2010). Diagnosis and management of Duchenne muscular dystrophy, part 2. The Lancet Neurology, 9(2), 177–189.

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