Myostatin-related muscle hypertrophy is a rare condition characterized by reduced body fat and increased muscle size. Affected individuals have up to twice the usual amount of muscle mass in their bodies. They also tend to have increased muscle strength. Myostatin-related muscle hypertrophy is not known to cause any medical problems, and affected individuals are intellectually normal.
Skeletal muscle size in an individual with myostatin-related muscle hypertrophy is measured by ultrasound examination, DEXA, or MRI. Subcutaneous fat pad thickness is measured by ultrasound or with a caliper. Molecular genetic testing for GDF8, the only gene known to be associated with myostatin-related muscle hypertrophy, is available on a research basis.
Myostatin-related muscle hypertrophy is not currently known to cause any medical complications.