Gabby Williams has the facial features and skin of a newborn, and she is just as dependent. Her mother feeds, diapers and cradles her tiny frame as she did the day she was born.
The little girl from Billings, Mont., is 8 years old, but weighs only 11 pounds. Gabby has a mysterious condition, shared by only a handful of others in the world, that slows her rate of aging.
For the past two years, a doctor who has been trying to find the genetic off-switch to stop the aging process has been studying Gabby, as well as two other people who have striking similarities.
A 29-year-old Florida man has the body of a 10-year-old, and a 31-year-old Brazilian woman is the size of a 2-year-old. Like Gabby, neither seems to grow older.
Unraveling what these three people may have in common is the subject of a TLC television special, "40-Year-Old Child: A New Case," which airs Monday, Aug. 19, at 10 p.m. ET. The show is a follow-up to Gabby's story, which aired last year.
"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."
For the rest of the story: http://abcnews.go.com/Health/girl-ages-unravel-secret-eternal-youth/story?id=19974247