It is possible that the key to immortality is hidden in this delicate girl, who is only about 76 centimeters (2 feet, 6 inches) tall and weighs seven kilograms (15.4 pounds). Her arms and legs are as fragile as the branches of a young tree. Her laugh sounds like the whimper of a puppy; she has hazel eyes. And when Brooke Greenberg wants her mother she stretches out her tiny arms, shakes her head slowly, and twists her face into a lopsided moue.
"Come here, Brooke, yes, you are a pretty girl." Melanie Greenberg, 49, picks up the fragile looking child and gently strokes her back. "She loves being held," says Greenberg, a mother of four. Brooke's sisters are named Emily, Caitlin and Carly. Brooke is the second youngest. She will be 18 in January.
Other girls her age are driving, going out dancing and sleeping with their first boyfriends. But for Brooke it's as if time had stood still. Mentally and physically, the girl remains at the level of an 11-month-old baby.
"Brooke is a miracle," says her father, Howard Greenberg. "Brooke is a mystery," says Lawrence Pakula, her pediatrician. "Brooke is an opportunity," says Richard Walker, a geneticist with the University of South Florida College of Medicine. They all mean the girl from Reisterstown, a small town in the US state of Maryland, who may hold the answer to a human mystery. At issue is nothing less than immortality: Brooke Greenberg apparently isn't aging.
She has no hormonal problems, and her chromosomes seem normal. But her development is proceeding "extremely slowly," says Walker. If scientists can figure out what is causing the disorder, it might be possible to unlock the mysteries of aging itself. "Then we've got the golden ring," says Walker.
He hopes to simply eliminate age-related diseases like cancer, dementia and diabetes. People who no longer age will no longer get sick, he reasons. But he also thinks eternal life is conceivable. "Biological immortality is possible," says Walker. "If you don't get hit by a car or by lightning, you could live at least 1,000 years."
An Unprecedented Case
Brooke Greenberg was born prematurely on Jan. 8, 1993 at Sinai Hospital in Baltimore, Maryland. She weighed only 1,800 grams (about four pounds) at birth. It soon became clear that she wasn't normal. Almost all of her organ systems were altered. Her hips were dislocated, so that her legs pointed awkwardly toward her shoulders. She'd hardly been born before she was placed in a cast.
The first six years were torture for Brooke and her parents. On one occasion, seven holes in the child's abdominal wall had to be repaired. Because food kept entering her windpipe instead of her stomach, a gastric feeding tube had to be inserted. She fell into a 14-day coma when she was four. Then doctors diagnosed a brain tumor (the diagnosis later proved to be incorrect). "The Greenbergs had gone out already and made the preparations, buying a coffin and talking to the rabbi," pediatrician Pakula recalls.
Pakula practices in a medical building near the Greenbergs' house. He wears a tie adorned with cartoonish hippopotamuses. A tall stack of paper -- Brooke's file -- sits on his desk. "This can't be lost," says the doctor, placing his hand on the documents. He knows what a treasure the file represents.
The most surprising thing about Brooke is that she hardly ages at all. Her body stopped growing when she was two years old. She hasn't grown a centimeter or gained a pound. Pakula injected the girl with growth hormones, but nothing happened. He studied the medical literature and consulted specialists worldwide. "She was presented to everybody who was anybody in the medical world at the time," says the 77-year-old pediatrician, "but she didn't match anything any physician had seen before."
The Greenbergs waited and hoped -- one year, two years, 10 years -- but nothing happened. Their daughter's facial features have remained unchanged. There are no signs of puberty. "Brooke's nurses, her teachers, even her father can't consistently sort photos of her chronologically," says Pakula. Only the girl's hair and fingernails are growing normally.
'She's a Miracle'
At the family's house in Reisterstown, Howard Greenberg points to photos on the walls: Brooke at three, next to her one-year-old sister Carly, who was already bigger than she was at the time; Brooke in a playsuit on her 12th birthday; Brooke at 14, at her Bat Mitzvah, the Jewish rite of initiation.
Greenberg hurries from picture to picture. Brooke looks the same in all the photos. Her mouth is always slightly lopsided and her eyes just a tough too far apart. "She's a miracle." It's something that has to be said, again and again. "What's she missing in life? Nothing. She hasn't got a worry in the world. She isn't broken. We're the ones who are broken." This is the father's way of explaining away his daughter's condition. "If you look at it that way, it makes it much more bearable," he says later on.
At first Melanie Greenberg took care of Brooke on her own, but now she has help. Feeding Brooke through the tube takes 10 hours a day. She goes to a school for disabled children from 7:30 a.m. to 3:30 p.m. Much of the rest of the time she spends in her room, sitting in her bed and watching television, or bobbing back and forth in her light-blue baby swing.
"She can do this all day," says Melanie Greenberg, lifting her daughter into the air and carefully placing her on her thin little legs, with her feet twisted inward. "It was not easy, it was very hard," she says, "but I'm sure there is a reason for Brooke to be here. Something is in her, something that could help millions of people."
The Disassociated Body
Richard Walker, a retired professor of medicine and specialist in the biology of aging, lives in a house on a lagoon in the coastal town of Indian Rocks, Florida. He became aware of Brooke Greenberg in 2005. "I thought right away that she had a unique mutation in key genes that control development and aging," he says. Walker contacted the Greenbergs and convinced the father to let him take a sample of Brooke's blood so that he could study her genetic makeup. He examined the number and condition of the chromosomes. He analyzed the so-called telomeres at the ends of chromosomes, the length of which provides information about the age of cells. He filled tiny reagent reservoirs made of biochips with pieces of genetic material, and tested the activity of a wide range of genes.
The results are as sobering as they are fascinating. "We haven't found anything unusual so far," says Walker, "but that wasn't a disappointment; it was actually an incentive to keep on searching."
The girl's uniqueness lies precisely in the fact that her genetic material seems normal, whereas she is obviously not normal, says the professor. Despite the surprisingly unremarkable genetic analysis, complete chaos prevails inside the girl's body.
Her brain is hardly more developed than an infant's, but her bones have a biological age of about 10 years. Her teeth, including her baby teeth, are like those of an eight-year-old. The length of the telomeres, on the other hand, corresponds to her actual age. In addition, the development of various organ systems, like the digestive tract, is what the professor calls "disassociated."
"Different parts of her body are developing at different rates, as if they were not a unit but parts of separate organisms," Walker explains. He believes that there is only one explanation -- a failure of central control genes.
Normally, a carefully orchestrated genetic program allows a tiny egg cell to grow into an adult body. But if this master plan is impaired, the marvel of growth goes awry. Walker believes that this is precisely what has happened with Brooke. Genes that play an important role in physical development are either inactive or defective. "If we identify those genes, we might be able to understand the development and subsequently the aging of the body," says the scientist.
An Eccentric Theory
Walker believes that aging is merely the continuation of the body's development. He uses the image of a house to illustrate his point. First the house is built. When it's finished -- or, in the case of the body, when sexual maturity is reached -- the construction crew would normally leave the site. But in normal people the construction workers stay and keep building, according to a plan that's been fulfilled and a construction supervisor who says nothing but nonsense. Soon the crew builds things like contorted bay windows and shaky dormers. Supporting beams are suddenly sawed off, and then walls start falling. Finally the building collapses completely -- and death catches up with the body.
"Aging happens when developmental genes merely run out of meaningful information and subsequently cause chaos," Walker says. His idea is to simply shut off the master genes of development. This, he hopes, will put a stop to the aging process. If Walker is right, the consequences will be dramatic. A body manipulated in this fashion would no longer change, but would only perform repair work. Eternal life would be within reach.
All this talk has exhausted the professor. He sits in his heavy armchair and gazes out at the glittering water. A dinghy and a motorboat are tied to his private jetty directly in front of the deck, and a surfboard is lying nearby. The doctor sails, surfs and skis. He is 71. He loves his life.
Does he want to be immortal?
"Of course I want to live forever," he says. "I could study mathematics; I could learn so many more things. It would be the greatest gift in the world." Many people, says Walker, imagine that eternal life would be nothing but hardship and senescence. "But that's not how it would be," says Walker. Ideally development would be arrested just after a person reaches sexual maturity.
And the social consequences? Who would be allowed to live forever, and who wouldn't? Who would be allowed to have children?
Walker hesitates. "These are ethical questions, not scientific questions," he says. "These would be arguments made by philosophers and priests."
Walker's theories are controversial. The British biologist Aubrey de Grey, for example, holds his American colleague in high esteem, but believes that aging and development are not related. The Brooke Greenberg case, says de Grey, has "absolutely nothing to do with aging." He points to the phase of life between the ages of 20 and 40, in which the body hardly changes at all. "Is it likely that the developmental gene expression suddenly stops during this time and then starts up again? No, this is highly unlikely," he says.
De Grey favors the standard theory that the body's cells simply wear out over the years, and that they accumulate toxins and lose their ability to regenerate. He has identified seven causes of death, like cell loss or changes in genetic material, which he hopes to combat with stem-cell therapy or special injections.
But Walker doesn't challenge the criticism. "The deterioration of the body's cells is precisely a consequence of the unregulated activity of development genes," he argues. His theory is seductive in a sense. While biologists like de Grey tamper with the countless symptoms of growing old, Walker simply wants to do away with aging altogether.
"Imagine we could stop the degenerative changes of the body," he says enthusiastically. "The onset of age-related diseases like diabetes, Alzheimer's, dementia and many forms of cancer could be prevented."
To prove his theory, Walker needs people like Brooke Greenberg, in whom the developmental master genes fail. He's already discovered two similar cases. Six-year-old Gabrielle K., from Billings, Montana, born Oct. 15, 2004, also doesn't seem to be aging much at all. At the same time her chromosomes, just like Brooke Greenberg's, seem completely normal.
Nicky Freeman, a 40-year-man who seems to be trapped in a boy's body, lives in Esperance in Western Australia. His biological age is estimated at 10 years.
All in the Genes
Can Gabrielle or Nicky point the way to the fountain of youth? Walker doesn't know yet. He is focusing his attention on Brooke at the moment. He wants to sequence the girl's entire DNA, together with experts from Duke University in Durham, North Carolina. If they find mutations in Brooke's genetic makeup, Walker plans to identify the corresponding genes in laboratory rats and then block them. He reasons that if the genetically manipulated remain young, researchers will in fact have put a stop to their development.
"Brooke holds the key to everything," says Walker. He's anxious to press on with his work, because he feels that his time is running out. But Howard Greenberg is stalling. He has long felt that he is protecting a valuable treasure in his red brick house. He's even hired lawyers to examine the issue of the rights to Brooke's genome. The father knows time is on his side. Doctors tell him that with good medical care his daughter can live a long time.
In the Greenberg home, Melanie has now attached a bag containing a complete nutritional formula to her daughter's feeding tube. The brownish flood runs through a tube into Brooke's small body.
Howard Greenberg looks down at his daughter. Wearing a red-and-white striped T-shirt and white pants, the girl rocks back and forth in his baby swing, as monotonously as a pendulum.
"I always thought she would die way before me, but I don't think that anymore," says the 53-year-old after a pause. "Brooke can live forever. She'll always be here."