Gabby Williams is eight years old but has the skin of a newborn and only weighs 11 lbs. An ultra-rare genetic condition, for which doctors have no discernible explanation, keeps Williams from physically aging and has her parents caring for her nearly the same as the day she was born.

Williams shares her rare condition with only a handful of people around the world, including a 29-year-old man from Florida who has the body of a 10-year-old, and a 31-year-old Brazilian woman who appears no older than two. While the medical community hasn’t yet established a cause for Williams’ or the others' conditions, research into the genetic disorder has promising implications for overcoming the inertia of aging.

"In some people, something happens to them and the development process is retarded," said medical researcher Richard F. Walker. "The rate of change in the body slows and is negligible."

The Science Behind It

Walker has been researching Williams’ condition for the last two years. Retired from the University of Florida Medical School, Walker now performs his research at All Children's Hospital in St. Petersburg. He reports having spent his entire career studying the causes of aging. The patients he deals with live with other conditions such as deafness and the inability to walk, eat, or even speak. But most notably, they all age at one-fifth the rate of a normal person.

Williams’ case is particularly noteworthy given her feature spot in the 2012 TLC documentary, “My 40-Year-Old Child.” Since the show aired, Williams’ parents told ABC News, their daughter has stayed relatively the same.

"Gabrielle hasn't changed since pretty much forever," said her mother, Mary Margret Williams, 38. "She has gotten a little longer and we have jumped into putting her in size 3-6 month clothes instead of 0-3 months for the footies.”

“Last time we weighed her she was up a pound to 11 pounds and she's gotten a few more haircuts,” she said, but other than that, things have remained the same.

Walker attributes Williams’ lack of aging to what he calls decreased “developmental inertia.” Her body’s normal physiological changes and maturation haven’t occurred because of the genetic condition. Normally when people age, their bodies mature until age 20 or so, and then begin to erode, or succumb to developmental inertia.

"If we could identify the gene and then at young adulthood we could silence the expression of developmental inertia, find an off-switch,” said Walker, adding that “when you do that, there is perfect homeostasis and you are biologically immortal."

Finding The Fountain Of Youth

Part of the reason humans can’t live forever is that as chromosomes split during cell division, the telomeres capping the chromosomes begin to shorten. Scientists often liken telomeres to the plastic tip on the end of a shoelace, as they keep the frayed ends of the chromosome from fusing together and degrading the cell’s blueprint.

Broken DNA is dangerous, and because of this a typical cell has the ability to repair chromosomal damage. Without telomeres, the cell would mistakenly sense broken DNA in the frayed chromosome. Doing so would cause the chromosome to stop dividing along with the rest of the cell and eventually die.

The result of overcoming developmental inertia isn’t living forever. It simply means old age wouldn’t come with greater risks of cancer, disease, and illness.

“You wouldn't have the later years,” Walker said. “You'd remain physically and functionally able.”

Aging isn’t only a process of telomere-shortening. Scientists include other factors such as oxidative stress, glycation, and chronological age. Oxidative stress, like glycation, is the compounding pressure put on DNA and lipids from oxidants. Glycation differs in that glucose is the main culprit, binding to and inhibiting DNA, proteins, and lipids. Chronological age refers to the number of years a person has been alive, and it reflects an increased risk for disease and illness.

In Gabby Williams’ case, her chronological age has little bearing on her outcome, although doctors cannot say with confidence how long they think she will live.

Devout Catholics, her parents accept their daughter’s fate however God intends it.

"When He is ready to take her back, it will be sad," her mother told ABC News. "But what a glorious thing it will be for Gabby to go to heaven one day. I know it will happen, but I am not hoping it's any day soon."