Duchenne muscular dystrophy (DMD) is a progressive neuromuscular disorder that primarily affects boys and begins in early childhood. It is the most common of the severe childhood-onset muscular dystrophies and produces steadily worsening skeletal, respiratory and cardiac muscle weakness. For general context about related conditions see muscular dystrophy.

Signs and clinical course

Symptoms typically appear between ages two and five with delayed motor milestones, frequent falls and difficulty running or climbing stairs. Weakness progresses from the pelvic girdle to the shoulder muscles and trunk. Many affected boys lose the ability to walk during childhood or early adolescence and develop spine curvature; surgical and orthotic treatment is often needed for scoliosis. Later complications include weakening of breathing muscles and heart muscle (cardiomyopathy).

Genetics and cause

DMD is inherited in an X‑linked recessive pattern: the defective gene lies on the X chromosome, so boys with a pathogenic change are usually affected while carrier females are typically asymptomatic or mildly affected. About two thirds of cases are transmitted through carrier mothers and roughly one third arise from a new, spontaneous change in the gene. For brief information on carrier transmission see carrier mothers and on spontaneous events see new mutations.

Pathophysiology

The condition results from mutations in the DMD gene, which encodes the structural protein dystrophin. Dystrophin helps stabilize muscle cell membranes during contraction; its absence or severe deficiency makes muscle fibers fragile and prone to degeneration. Over time muscle tissue is replaced by fat and fibrotic tissue, reducing strength and function.

Diagnosis, management and prognosis

  • Diagnosis: clinical assessment, elevated serum muscle enzymes, genetic testing to identify mutations, and sometimes muscle biopsy.
  • Supportive care: multidisciplinary management includes physical therapy, mobility aids, braces, and spinal care to preserve function and comfort.
  • Medical treatments: corticosteroids can slow decline in strength; cardiac and respiratory complications are managed with standard heart and breathing therapies, including noninvasive ventilation when needed.
  • Emerging therapies: molecular approaches such as exon‑skipping and gene‑based treatments are under development and may be offered in specialized settings or trials.

Early diagnosis and coordinated long‑term care can improve quality of life and extend survival. Ongoing research aims to refine genetic and regenerative therapies that address the underlying defect rather than only symptoms.

For further reading and resources consult specialist clinics and advocacy organizations that maintain up‑to‑date guidance and support for families affected by DMD.