Duchenne muscular dystrophy (DMD) is a severe type of muscular dystrophy characterized by the rapid progression of muscle degeneration, leading to loss of ambulation and premature death. DMD primarily affects boys, with onset typically occurring between ages 2 and 5.

Genetics and Pathophysiology:

Mutations in the DMD gene, which encodes the protein dystrophin, cause DMD. Dystrophin is crucial for maintaining the integrity of muscle cell membranes. Without functional dystrophin, muscle fibers are susceptible to damage, leading to muscle degeneration and weakness. The DMD gene is located on the X chromosome, making the disease X-linked recessive. This implies that the disease primarily affects males with one X chromosome, while females with two X chromosomes typically carry the gene.

Symptoms:

Early signs of DMD include:

• Delayed motor milestones, such as walking later than usual, are common.
• Difficulty running, jumping, and climbing stairs
• Frequent falls
• Enlarged calf muscles (pseudohypertrophy)
• Gower's sign involves using hands to push off the thighs when rising from the floor.
• As the disease advances,
• Muscle weakness spreads from the legs to the arms, neck, and other areas.
• Scoliosis (curvature of the spine) may develop.
• Cardiomyopathy (heart muscle weakness) and respiratory issues become prevalent.

Diagnosis:

DMD diagnosis typically involves:

• Clinical evaluation: observation of symptoms and family history.
• Creatine Kinase (CK) Levels: Elevated CK levels indicate muscle damage.
• Genetic testing identifies mutations in the DMD gene.
• Muscle Biopsy: Examines muscle tissue for the absence of dystrophin protein.

Management and Treatment:

While there is no cure for DMD, various treatments aim to manage symptoms and improve quality of life, including:.

• Corticosteroids help slow muscle degeneration.
• Cardiac Care: Includes medications and regular monitoring.
• Respiratory Care: Non-invasive ventilation and cough assist devices.
• Physical therapy maintains muscle strength and flexibility.
• Assistive Devices: Braces, wheelchairs, and other mobility aids.

Recent Advances:

• Gene Therapy: Efforts are underway to deliver functional copies of the DMD gene or to use CRISPR/Cas9 to correct mutations.
• Exon Skipping: Drugs like eteplirsen enable cells to skip over faulty parts of the gene, producing partially functional dystrophin.
• Stem Cell Therapy: Research is ongoing to develop stem cell treatments to regenerate damaged muscle tissue.

Prognosis:

With advances in medical care, the prognosis for people with DMD has improved. In the past, many boys with DMD did not survive beyond their teens. However, with thorough management, individuals can now live into their 30s and beyond. Early intervention and multidisciplinary care are crucial for extending life expectancy and enhancing the quality of life.

Support and Resources:

Organizations like the Muscular Dystrophy Association (MDA) and Parent Project Muscular Dystrophy (PPMD) offer resources, support, and advocacy for individuals with DMD and their families. They provide information on clinical trials and research advancements, as well as connecting families with medical professionals and support networks.