"If she was 12 years old, I'd say 12 months old. If she was 14 I'd say 14 months old. She's going to be 18 years old. I can't say 18 months anymore because she doesn't look 18 months," said Melanie Greenberg, Brooke's mother.
Brooke weighs 16 pounds and is 30 inches tall.
"The only thing that grows on Brooke is her hair and believe it or not, her fingernails," said Howard Greenberg, Brooke's father.
Dr. Richard Walker, of the University of South Florida College of Medicine, has dedicated his life's work to unraveling the mystery of aging. He believes Brooke's aging gene is not turned on.
"If we can locate those genes in Brooke's DNA, then we can test them for their putative effects on development and aging," said Walker.
Brooke ages one year for every 20 years. A close examination of her chromosomes reveals very little, but doctors did find that different parts of her body age at different rates.
"She is basically a mosaic. She's not developing as a unit organism," said Walker.
Her brain is the age equivalent of an infant. She still has all of her baby teeth. Her bone age is 10 years old and certain cellular markers equal her chronological age.
If Walker can find the anomaly in Brooke, it could change the future for others.
"Their misfortune, their mutation gives us a way to localize the genes that we don't know cause aging in us," said Walker. "That damage is basically a marker. It's a flag. So say 'This is the place to look.'"
If found, Walker hopes it could stop cancer from spreading, slow Alzheimer's, and more.
"If we could stop the process of decay, slow as it is, then we would extend the productive years," said Walker. "What if we had an Einstein that spent another hundred years as a young man?"
Unraveling the mystery of aging through a child who can't grow up: "And how apropos, to put the secret of this in a little child," said Brooke's father, Howard.