At first glance, Gabby Williams looks like an infant in the arms of her parents. But the little girl from Billings, Mont., is actually 8 years old. Because of an extremely rare genetic disorder that dramatically slows down her aging process, Gabby is still totally dependent on her parents, who must change her diaper, feed her and help her with almost everything. Gabby's condition, seen only in a few other known cases, has intrigued researchers.

Gabby's mother, Mary Margaret Williams, 38, said her daughter has only gotten slightly longer in eight years.

"Gabrielle hasn't changed since pretty much forever. We have jumped into putting her in size 3-6 month clothes instead of 0-3 months for the footies," Mary Margret said. "Last time we weighed her she was up a pound to 11 pounds and she's gotten a few more haircuts. Other than that, she hasn't changed much."

Gabby is among a very limited group of people with the genetic disorder, so rare that scientists and doctors have yet to name it. The other two cases involve a 29-year-old man from Florida who looks like a 10-year-old and a 31-year-old woman from Brazil who is around the size of a 2-year-old.

Identifying the genes responsible for the condition could open up more research about the aging process.

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