In most dystrophinopathies, which muscle groups are affected earliest?

• A. Proximal hip and thigh muscles
• B. Distal forearm muscles
• C. Facial muscles
• D. Calf muscles

Answer: (A)

Proximal hip and thigh muscles are the first to show weakness in dystrophinopathies. Dystrophin helps keep muscle membranes stable during contraction, and without it the muscles that generate the most force and are used for powerful, proximal movements—like hip girdle and thigh muscles—sustain damage early. This leads to early difficulties with tasks such as standing up from the floor, climbing stairs, and running. Calf enlargement due to fat and connective tissue replacement (pseudohypertrophy) is common and noticeable, but the strength loss starts in the proximal groups, not the calves themselves. Distal forearm muscles and facial muscles are typically affected later, which is why the earliest clinical picture centers on proximal weakness of the hips and thighs.