Muscle hypertrophy (MSLHP) is defined as an increase in muscle mass, as a result of an increase in the size of pre-existing muscle fibers. A myostatin mutation in a child with muscle hypertrophy has been identified. Myostatin, a member of the TGF-beta superfamily, is a potent negative regulator of skeletal muscle growth. Myostatin inactivation can induce muscle hypertrophy.
