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Gene mutation makes baby super strong
(Agencies)
Updated: 2004-06-25 09:00
Somewhere in Germany is a baby Superman, born in Berlin with bulging arm and
leg muscles. Not yet 5, he can hold seven-pound weights with arms extended,
something many adults cannot do. He has muscles twice the size of other kids his
age and half their body fat.
DNA testing showed why: The boy has
a genetic mutation that boosts muscle growth.
The discovery, reported in Thursday's New England Journal of Medicine,
represents the first documented human case of such a mutation.
Many scientists believe the find could eventually lead to drugs for treating
people with muscular dystrophy and other muscle-destroying conditions. And
athletes would almost surely want to get their hands on such a drug and use it
like steroids to bulk up.
The boy's mutant DNA segment was found to block production of a protein
called myostatin that limits muscle growth. The news comes seven years after
researchers at Johns Hopkins University in Baltimore created buff "mighty mice"
by "turning off" the gene that directs cells to produce myostatin.
"Now we can say that myostatin acts the same way in humans as in animals,"
said the boy's physician, Dr. Markus Schuelke, a professor in the child
neurology department at Charite/University Medical Center Berlin. "We can apply
that knowledge to humans, including trial therapies for muscular dystrophy."
Disease relief
Given the huge potential market for such drugs, researchers at universities
and pharmaceutical companies already are trying to find a way to limit the
amount and activity of myostatin in the body. Wyeth has just begun human tests
of a genetically engineered antibody designed to neutralize myostatin.
A
seven-month old baby with a genetic mutation that boosts muscle growth is
seen in an undated black and white image released by the New England
Journal of Medicine on Wednesday June 23, 2004. The discovery, reported in
Thursday's New England Journal of Medicine, represents the first
documented human case of such a mutation. The boy's mutant DNA segment was
found to block production of a protein called myostatin that limits muscle
growth. [AP] | Dr. Lou Kunkel, director of the genomics program at Boston Children's
Hospital and professor of pediatrics and genetics at Harvard Medical School,
said success is possible within several years.
"Just decreasing this protein by 20, 30, 50 percent can have a profound
effect on muscle bulk," said Kunkel, who is among the doctors participating in
the Wyeth research.
Muscular dystrophy is the world's most common genetic disease. There is no
cure and the most common form, Duchenne's, usually kills before adulthood. The
few treatments being tried to slow its progression have serious side effects.
Muscle wasting also is common in the elderly and patients with diseases such
as cancer and AIDS.
"If you could find a way to block myostatin activity, you might slow the
wasting process," said Dr. Se-Jin Lee, the Johns Hopkins professor whose team
created the "mighty mice."
Lee said he believes a myostatin blocker also could suppress fat accumulation
and thus thwart the development of diabetes. Lee and Johns Hopkins would receive
royalties for any myostatin-blocking drug made by Wyeth.
Boy's background, future
Dr. Eric Hoffman, director of Children's National Medical Center's Research
Center for Genetic Medicine, said he believes a muscular dystrophy cure will be
found, but he is unsure whether it will be a myostatin-blocking drug, another
treatment or a combination, because about a dozen genes have some effect on
muscles.
He said a mystotatin-blocking drug could help other groups of people,
including astronauts and others who lose muscle mass during long stints in zero
gravity or when immobilized by illness or a broken limb.
Researchers would not disclose the German boy's identity but said he was born
to a somewhat muscular mother, a 24-year-old former professional sprinter. Her
brother and three other close male relatives all were unusually strong, with one
of them a construction worker able to unload heavy curbstones by hand.
In the mother, one copy of the gene is mutated and the other is normal; the
boy has two mutated copies. One almost definitely came from his father, but no
information about him has been disclosed. The mutation is very rare in people.
The boy is healthy now, but doctors worry he could eventually suffer heart or
other health problems.
In the past few years, scientists have seen great potential in
myostatin-blocking strategies.
Internet marketers have been hawking "myostatin-blocking" supplements to
bodybuilders, though doctors say the products are useless and perhaps dangerous.
Some researchers are trying to turn off the myostatin gene in chickens to
produce more meat per bird. And several breeds of cattle have natural variations
in the gene that, aided by selective breeding, give them far more muscle and
less fat than other steer.
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