Navigating the Heterogeneous Progression of Duchenne Muscular Dystrophy

Summary for Physicians

Disease Progression in Duchenne Muscular Dystrophy (DMD)DMD
DMD progresses in stages, with initial motor milestone delays and a gradual loss of motor function. Key points include the following:

• Early delays in motor milestones like such as standing, walking, running, and climbing stairs.
• Maximum motor capacity typically achieved by age 6.5½, followed by a noticeable decline in function. Some children may lose the ability to walk as early as age 7 to -8 years, while others may progress more slowly.
• Wide range of progression: Some mutations (e.g.eg, those amenable to Eexon 44 skipping) may result in slower progression and less severe weakness.
• Dystrophin deficiency leads to muscle cell damage and affects multiple organs, including the heart, lungs, and digestive system, contributing to the disease's progressive nature.
• Respiratory and cardiac involvement develop with age, and early death was common before the use of steroids and other therapies.
• Prognosis improvement: With steroids and new therapies, life expectancy has increased, and newborn screening may further improve outcomes by enabling earlier interventions.