A novel potential therapy based on a natural human protein significantly slows muscle damage and improves function in mice who have the same genetic mutation as boys with the most common form of muscular dystrophy. Now headed toward human trials, biglycan significantly slows the weakening of muscles in mice with the genetic mutation that causes muscular dystrophy. Biglycan causes utrophin,a natural muscle-building protein prevalent in young children, to collect in muscle cell membranes.