Duchenne muscular dystrophy (DMD) is a rare, inherited condition that causes progressive muscle weakness and loss. It primarily affects boys and is caused by a genetic mutation that prevents the body from producing dystrophin, a protein essential for muscle strength and function. This guide explains DMD, its causes, symptoms, treatments, and how to manage living with it.

What is Duchenne Muscular Dystrophy?

DMD is a genetic disorder that leads to the gradual weakening and wasting of muscles. It is part of a group of conditions known as muscular dystrophies, which all involve muscle degeneration. DMD specifically affects skeletal muscles (used for movement), the heart, and respiratory muscles.

The condition is progressive, meaning symptoms worsen over time. While there is currently no cure, treatments can help manage symptoms and improve quality of life.

Background on Duchenne Muscular Dystrophy

• History: DMD was first described in the 1860s by French neurologist Guillaume Duchenne.
• Global Impact: It is one of the most common forms of muscular dystrophy in children and has significant effects on individuals and their families due to its progressive nature.

Causes, Incidence, and Prevalence

Causes

DMD is caused by mutations in the DMD gene, which provides instructions for making dystrophin. Dystrophin is a protein that helps protect muscle fibres from damage during movement. Without it, muscles weaken over time.

• The condition is inherited in an X-linked recessive pattern, meaning the faulty gene is located on the X chromosome. Boys are primarily affected because they have only one X chromosome. Girls can be carriers and may have mild symptoms but are rarely severely affected.

Incidence and Prevalence

• Incidence: Approximately 1 in 3,500 to 1 in 5,000 boys are born with DMD worldwide each year.
• Prevalence: Around 250,000 people globally live with DMD or related muscular dystrophies.

Who is Affected?

1. Age of Onset: Symptoms typically appear between the ages of 2 and 6 years old.
2. Gender: Almost exclusively affects boys; girls are usually asymptomatic carriers but may experience mild muscle weakness in rare cases.
3. Ethnicity: DMD affects all ethnic groups equally.

Geographic Distribution

DMD occurs worldwide without significant differences in prevalence between regions.

How Does Duchenne Muscular Dystrophy Impact You?

Symptoms

Symptoms of DMD usually begin in early childhood and progress over time:

• Early Symptoms (ages 2–6):
  • Difficulty running, jumping, or climbing stairs.
  • Frequent falls or clumsiness.
  • Enlarged calf muscles (pseudohypertrophy).
• Progressive Symptoms (ages 6–12):
  • Worsening muscle weakness, particularly in the legs and pelvis.
  • Difficulty walking; many children need a wheelchair by their early teens.
  • Weakness in arms and shoulders.
• Later Symptoms (teenage years onward):
  • Weakness in respiratory muscles, leading to breathing difficulties.
  • Heart problems (cardiomyopathy) due to weakening of the heart muscle.
  • Scoliosis (curvature of the spine) due to weakened back muscles.

Living With Duchenne Muscular Dystrophy

Living with DMD involves managing physical limitations while addressing emotional and social challenges. Many families require support from healthcare providers, therapists, and community organisations.

Expected Life Expectancy

Life expectancy for individuals with DMD has improved significantly due to advances in care. Many people now live into their late 20s or early 30s, with some reaching their 40s or beyond with appropriate treatment.

Managing and Treating Duchenne Muscular Dystrophy

Available Treatments

While there is no cure for DMD, treatments focus on slowing disease progression, managing symptoms, and improving quality of life:

1. Medications:
   1. Corticosteroids: Drugs like prednisone or deflazacort can slow muscle degeneration and improve strength temporarily.
   2. Heart Medications: ACE inhibitors or beta-blockers may be prescribed to manage cardiomyopathy.
   3. Exon Skipping Therapies: Newer treatments like eteplirsen target specific genetic mutations to help produce functional dystrophin protein.

2. Physical Therapy:
   1. Regular physiotherapy helps maintain flexibility, reduce contractures (stiffness), and support mobility.
   2. Stretching exercises can prevent joint deformities.

3. Assistive Devices:
   1. Wheelchairs or mobility aids improve independence as walking becomes more difficult.
   2. Braces or orthotics may be used to support weakened muscles.

4. Respiratory Support:
   1. Non-invasive ventilation devices help with breathing as respiratory muscles weaken.
   2. Cough assist machines can clear mucus from the lungs.

5. Surgery:
   1. Procedures may be needed to correct scoliosis or address complications like contractures.

Ongoing Clinical Research

Research into DMD continues to explore new therapies aimed at slowing disease progression or repairing damaged muscles:

1. Gene Therapy: Scientists are investigating ways to replace or repair faulty dystrophin genes using advanced genetic techniques like CRISPR-Cas9.
2. Stem Cell Therapy: Studies are exploring whether stem cells can regenerate damaged muscle tissue.
3. New Medications: Trials are underway for drugs targeting inflammation or fibrosis (scarring) in muscles.
4. For information on clinical trials related to DMD, visit clinicaltrials.gov.

Support Groups and Resources

If you or your child has been diagnosed with Duchenne muscular dystrophy, connecting with support groups can provide valuable information and emotional support:

1. Muscular Dystrophy UK (musculardystrophyuk.org) – Offers resources for patients and families living with muscular dystrophies in the UK.
2. Parent Project Muscular Dystrophy (PPMD) (parentprojectmd.org) – Focuses on education, advocacy, and research funding for individuals with Duchenne muscular dystrophy.
3. CureDuchenne (cureduchenne.org) – Supports research into treatments for Duchenne muscular dystrophy.
4. Rare Disease UK (raredisease.org.uk) – Provides resources for individuals living with rare conditions like DMD.

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Remember:

This information is intended for general knowledge and educational purposes only and does not constitute medical advice. It is essential to consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.

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