Early pathological signs in young dysf -/- mice are improved by halofuginone.

•Dysferlinopathies are a group of late-onset muscular dystrophies.•Impaired fusion of primary dysf −/− myoblasts from young mice.•Elevated fibrotic symptoms are found in dysf−/− mice at 4 weeks of age.•Early halofuginone treatment rescues dysf−/− mouse muscle histopathology.•Early halofuginone treatment improves myoblast fusion in dysf−/− mice.