Myostatin (MSTN) is a transforming growth factor-ß family member that normally acts to limit skeletal muscle mass. Mice engineered to lack myostatin exhibit about a doubling of skeletal muscle mass throughout the body. Moreover, pharmacological agents capable of inhibiting myostatin
signaling can cause significant muscle growth when administered systemically to normal adult mice. The sequence of myostatin has been highly conserved through evolution, and naturally-occurring mutations in the MSTN gene leading to increased muscling have been identified in cattle, sheep, dogs, and humans. Beneficial effects of myostatin loss have been demonstrated in numerous experimental models of muscle degenerative and wasting conditions as well as metabolic diseases. Based on the results of these preclinical studies, several pharmaceutical and biotechnology companies have entered clinical trials with myostatin inhibitors to attempt to improve muscle growth and function in patients with muscle loss.
Myostatin (also known as growth differentiation factor 8, abbreviated GDF-8) is a myokine, a protein produced and released by myocytes that acts on muscle cells' autocrine function to inhibit myogenesis: muscle cell growth and differentiation. In humans it is encoded by the MSTN gene. Myostatin is a secreted growth differentiation factor that is a member of the TGF beta protein family.
A technique for detecting mutations in myostatin variants has been developed. Mutations that reduce the production of functional myostatin lead to an overgrowth of muscle tissue. Myostatin-related muscle hypertrophy has an incomplete autosomal dominance pattern of inheritance. People with a mutation in both copies of the MSTN gene in each cell (homozygotes) have significantly increased muscle mass and strength. People with a mutation in one copy of the MSTN gene in each cell (heterozygotes) have increased muscle bulk, but to a lesser degree.