Why does Becker muscular dystrophy usually progress more slowly than Duchenne muscular dystrophy?

Becker muscular dystrophy (BMD) typically progresses more slowly than Duchenne muscular dystrophy (DMD) because of differences in the production of the protein dystrophin.

While both conditions are X-linked genetic disorders caused by mutations in the DMD gene, the underlying pathology differs significantly:

• Duchenne muscular dystrophy: This form is characterized by the near-total absence of functional dystrophin. Without this critical protein, which protects muscle cell membranes during contraction, muscle cells become weak and break down over time, leading to rapid degeneration.12
• Becker muscular dystrophy: In contrast, individuals with this form of the disease still produce some functional dystrophin. The presence of this partial protein allows for better muscle cell stability compared to DMD, which accounts for the later onset of symptoms and the slower rate of disease progression.1

Because of this, individuals with Becker muscular dystrophy may remain functional well into adult life, whereas Duchenne muscular dystrophy typically results in more severe, early-onset muscle wasting and a significantly shorter life expectancy.12