Rando and Biressi knew that a similar, but much less pronounced, accumulation of connective tissue in muscle fibers occurs during normal aging. That process is governed by signaling proteins, which include the Wnt and TGF-beta protein families. Wnt plays a critical role in embryonic development and cancer; TGF-beta controls cell division and specialization. They wondered whether blocking the Wnt/TGF-beta pathway in the dystrophic mice would inhibit fibrosis in the animals’ muscles.