The young girl from Billings, Mont. is the subject of an upcoming TLC television series, "40-Year-Old Child: A New Case," which airs Monday, Aug. 19, at 10 p.m. EST.
Her medical condition, shared by just a handful around the world, does not allow her body to age the same way as others.
"Gabrielle hasn't changed since pretty much forever," her mother, Mary Margret Williams, 38, tells ABC. "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."
Richard F. Walker, a medical researcher working closely with Gabby, tells the news network that he is fascinated by what her condition can teach science about the process of aging.
"In some people, something happens to them and the development process is retarded," says Walker. "The rate of change in the body slows and is negligible."
The process of "developmental inertia" is essentially the medical term for what we recognize as aging. And Walker claims he may have identified the exact gene mutation responsible for stopping developmental inertia in people with Gabby's condition. Understanding which gene mutation is responsible for Gabby's condition can have major implications for science.
"If we could identify the gene and then at young adulthood we could silence the expression of developmental inertia, find an off-switch, when you do that, there is perfect homeostasis and you are biologically immortal," he says.
The idea of being immortal understandably doesn't appeal to everyone, but Walker clarifies that disease and accidents will still end human life. Being immortal, in this case, means that humans would remain physically and functionally able till their death.
The Globe and Mail recently explained how scientists have been working on the process of immortality and suggest that the average lifespan could rise by decades, perhaps to 120 years. Scientists at the Albert Einstein College of Medicine have tinkered with a protein in a tiny part of the brain called the hypothalamus that is thought to control the aging process.
It's worth noting that a recent survey of Canadians, published in the Journal of Aging Studies, found 59 per cent of respondents would welcome living 120 years “if science made it possible to do so in good health.”
As for Williams, despite not being given an expected lifespan for her daughter Gabby, she remains optimistic as a devout Catholic that when her daughter's time to go comes, it will be for the best.
"It's not something I worry about," says Williams. "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."