Compared with Duchenne, Becker muscular dystrophy typically has which characteristic regarding onset and severity?

• A. Earlier onset and more severe
• B. Similar onset and severity
• C. Later onset and milder symptoms
• D. No muscle weakness

Answer: (C)

Dystrophin gene mutations cause both Duchenne and Becker muscular dystrophy, but the amount of functional dystrophin left explains the difference in how the diseases present. Becker tends to have some dystrophin function preserved, so the disease progresses more slowly and symptoms start later. Clinically, this means Becker looks milder and appears after childhood, whereas Duchenne shows up in early childhood with rapid, more severe weakness. That’s why the correct description is later onset and milder symptoms.

An earlier onset and more severe course is characteristic of Duchenne, not Becker; a statement of similar onset/severity wouldn’t match Becker’s typically milder, later presentation; and while Becker does involve muscle weakness, saying there is no weakness isn’t accurate.