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Foundation Sciences · Genetics

Duchenne and Becker Muscular Dystrophy

⏱️ 30 mins read 📖 Genetics 🎯 MLA Relevance: High

Duchenne (DMD) and Becker (BMD) muscular dystrophies are X-linked recessive disorders of the dystrophin gene causing progressive muscle weakness.

📌 Learning Objectives

  • Describe the underlying mechanism of Duchenne and Becker Muscular Dystrophy.
  • Identify the key clinical features and complications of Duchenne and Becker Muscular Dystrophy.
  • Outline the appropriate investigations and management of Duchenne and Becker Muscular Dystrophy.
  • Discuss the implications for patients and families of Duchenne and Becker Muscular Dystrophy.
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Curriculum Mapped
UK MLA Curriculum

📋 Overview

DMD presents around age 3–5 with Gowers sign, calf pseudohypertrophy and proximal weakness; loss of ambulation by age 12. Cardiomyopathy and respiratory failure cause death in early adulthood without treatment.

🔬 Basic Science

DMD presents around age 3–5 with Gowers sign, calf pseudohypertrophy and proximal weakness; loss of ambulation by age 12. Cardiomyopathy and respiratory failure cause death in early adulthood without treatment.

🏥 Clinical Relevance

Corticosteroids slow progression; new therapies (e.g. exon-skipping) for selected mutations.

🧪 Investigations

Investigation depends on clinical context: relevant blood tests, imaging, and specific genetic or histopathological tests as appropriate. Refer to specialist services where indicated.

💊 Management

Management is condition-specific and typically multidisciplinary, combining medical therapy, surgical intervention where appropriate, supportive care, and family/genetic counselling.

Revision Resources – expand the sections below for high-yield notes, exam pearls, key facts and further reading.

🎯 MLA High-Yield Notes & Quick Revision ⌄
Common SBA themes: recognising the underlying mechanism, identifying classic clinical features, and choosing the first-line investigation or management step. Watch for inheritance pattern and characteristic associations.
duchenne becker dystrophin gowers sign x-linked
  • DMD is X-linked recessive; mothers are carriers.
  • Gowers sign and calf pseudohypertrophy are classic features.
  • Loss of ambulation typically occurs around age 12 in DMD.
  • Becker is a milder allelic variant with later onset.
  • Cardiomyopathy is common; baseline and follow-up echocardiography are essential.
⭐ Exam Pearls ⌄
⭐ High Yield
DMD is X-linked recessive; mothers are carriers.
Gowers sign and calf pseudohypertrophy are classic features.
Loss of ambulation typically occurs around age 12 in DMD.
Becker is a milder allelic variant with later onset.
Cardiomyopathy is common; baseline and follow-up echocardiography are essential.
💡 Clinical Pearl
Duchenne: Corticosteroids slow progression; new therapies (e.g. exon-skipping) for selected mutations.
⚠️ Exam Tip — Common Mistakes
Confusing the mechanism of Duchenne and Becker Muscular Dystrophy with related conditions.
Missing classic clinical features of Duchenne and Becker Muscular Dystrophy in SBA stems.
Failing to consider Duchenne and Becker Muscular Dystrophy in the differential diagnosis.
🔑 Key Facts ⌄
DMD is X-linked recessive; mothers are carriers.
Gowers sign and calf pseudohypertrophy are classic features.
Loss of ambulation typically occurs around age 12 in DMD.
Becker is a milder allelic variant with later onset.
Cardiomyopathy is common; baseline and follow-up echocardiography are essential.
🔗 Related Topics ⌄
🔬 X-Linked Disorders Foundation Sciences → 📚 Muscular Dystrophy 📚 Cardiomyopathy
📚 References ⌄
  1. GMC MLA Content Map
  2. NICE Clinical Knowledge Summaries
  3. BMJ Best Practice

Further Resources

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