An anonymous reader writes to tell us that a baby boy with unusually big muscles — caused by a gene mutation — is helping scientists to discover new muscular dystrophy drugs. "Myostatin was discovered in mice in 1992 in Lee's Johns Hopkins lab. In 1996 he proved its importance by showing that mice without the myostatin-producing gene got twice as big. The next year he discovered that the bulging Belgian Blue cow was a myostatin mutant, the first of eight prized cattle breeds later found to have the mutation. The company he had co-founded, MetaMorphix, is working on manipulating myostatin to beef up livestock. Wyeth picked up the rights to develop a drug for humans. Its experimental antibody drug produced bulked-up mice in 2002, and results of a trial in adults with muscular dystrophy are expected as early as March."