Muscle-Bound Boy Offers Hope for Humans

Scientists Work to Isolate Secrets of a Genetic Mutation That Could Alleviate Weakness Accompanying Disease and Aging

As soon as he was born, doctors noticed something odd about the boy: He had unusually large muscles, which bulged from his little arms and legs.

Today, the 4 1/2-year-old is extraordinarily strong: Most children his age can lift about one pound with each arm -- he can hold a 6.6-pound dumbbell aloft with each outstretched hand. Otherwise, the boy appears normal, at least so far.

But scientists say the child is much more than a curiosity -- he could help them develop new treatments for a host of muscle disorders, most notably muscular dystrophy, and perhaps find ways to prevent the inexorable frailty that accompanies aging. He is the first human confirmed to have a defect in a gene that scientists have suspected could lead to new approaches for building muscles in people.

"This will certainly intensify efforts to move forward aggressively on this research," said Se-Jin Lee, a professor of molecular biology and genetics at the Johns Hopkins Medical Institutions in Baltimore, who helped study the boy.

At least one drug company, Wyeth Pharmaceuticals, has begun preliminary testing of a drug designed to mimic the effects of the defective gene as a possible treatment for the most common form of muscular dystrophy, a devastating muscle disease that primarily afflicts boys.

At the same time, the discovery is raising concerns that athletes and body-builders will try to exploit the discovery to enhance their abilities, and some companies are already marketing products that claim to use the approach.

"Athletes find a way of using just about anything," said Elizabeth M. McNally of the University of Chicago, who wrote an article accompanying the findings in last week's New England Journal of Medicine. "This, unfortunately, is no exception."

The new research on the muscle-bound German boy follows work reported in 1997, when Lee and his colleagues used genetic engineering to create a breed of mouse with muscles at least twice as big as those of normal mice.

The rodents, dubbed "mighty mice," created a sensation. They also triggered a flurry of research by scientists hoping to use the work to help cure human ailments, including muscular dystrophy, cachexia -- a muscle-wasting condition that affects cancer and AIDS patients -- and perhaps the normal muscle weakening that comes with aging, called sarcopenia.

"That's a major health problem throughout the world. As people get older, and weaker, they are more susceptible to falling down and breaking bones, and those things have major health consequences," Lee said.

In agriculture, researchers hope it could lead to genetically engineered animals that would provide more meat. "If we could interfere with this gene in livestock, the idea was that we could improve meat production," Lee said.

In fact, scientists quickly determined that some breeds long prized for their massive muscles, such as Belgian Blue cattle, had naturally occurring mutations in the same gene the scientists altered to produce the mighty mouse.

The gene's instructions direct muscle cells to produce a protein known as myostatin, which regulates the growth of new muscle. When the gene is deactivated, muscles grow unusually large.

But while the findings in animals raised hopes that the gene played the same role in humans, there was no direct evidence of that.