Bulked-Up Boy Teaches Docs About Muscle Protein
Wed 23 June, 2004 22:03

By Gene Emery

BOSTON (Reuters) - Doctors are studying a 5-year-old German boy whose upper arms and legs are almost twice the size of his peers to learn what happens when the body does not produce a protein that limits muscular development.

The boy, whose mother is a professional athlete in Germany, is far stronger than other boys his age and lacks the protein, known as myostatin, doctors reported in Thursday's New England Journal of Medicine.

He appears healthy now, but researchers are concerned the child may eventually develop abnormalities in the heart, which is a muscle.

The discovery could help doctors find a chemical to increase muscle mass as a treatment for several medical problems, such as muscular dystrophy, or the muscle deterioration seen in the elderly and among people in the advanced stages of cancer.

Products that claim to regulate myostatin, most of them untested, are already being used by athletes and bodybuilders looking for an easier way to bulk up, Elizabeth McNally, of the University of Chicago, said in a Journal commentary.

But for now, the discovery confirms in humans what doctors discovered in rodents years ago -- that myostatin is an important regulator of muscle growth.

Deactivating the gene that makes myostatin creates "mighty mice" that are twice as muscular as their siblings.

"That gives us a great deal of hope that agents already known to block myostatin activity in mice may be able to increase muscle mass in humans too," said Dr. Se-Jin Lee of Johns Hopkins, a co-author of the study.

The child reportedly had an unusually strong mother, uncle, grandfather and great grandfather, according to the team of researchers led by Dr. Markus Schuelke of the Charite University Medical Center Berlin, in Germany.

The grandfather, for example, was a construction worker who could unload curbstones by hand.

While the cells of most people have two copies of the gene that makes myostatin, the doctors found that the boy's mother, the only person available for genetic analysis, had only one. The boy himself had no copies of the gene.

McNally said the research held great promise for the treatment of diseases that destroy the muscles but warned "the potential for abuse outside of the medical arena is substantial" and further studies of the long-term consequences are needed."