Tiny Liver Transplant Patient to Taste First Thanksgiving

— -- Born with a rare metabolic disease that rendered eating protein poisonous, 3-year-old Kennedy Stevenson was never able to appreciate a good bite of Thanksgiving turkey.

But all of that is about to change thanks to a liver transplant she received two weeks ago from her mother's Facebook friend.

"She just ate a chicken finger for the first time ever," her mother, Donya McCoy, told ABC News today from Children's Hospital of Pittsburgh, where Kennedy underwent her transplant and will remain an inpatient through the holidays.

Kennedy wasn't so sure about the chicken, McCoy said, but she loved her first taste of chocolate milk.

"Her eyes got big and she just kept sucking the straw," McCoy said. "She didn't want to stop."

Kennedy was diagnosed with a rare metabolic disorder called S-adenosylhomocysteine hydrolase deficiency. It's so rare that only eight people have ever been diagnosed with it, six of whom are still alive today, McCoy said.

The enzyme deficiency prevents Kennedy from processing protein normally, leading to a buildup of other toxic substances in her system and causing degenerative neurological effects over time, said Dr. George Mazariegos, chief of pediatric transplantation at Children's Hospital of Pittsburgh. Although other doctors had changed Kennedy's diet to eliminate protein and make it "stricter than vegan," McCoy said they decided that a liver transplant was her best chance for survival because the deficiency was concentrated in her liver tissue.

In the two weeks since the transplant, McCoy said doctors told her the new liver was "kicking butt." Levels of the toxic byproduct that used to build up because Kennedy couldn't process protein are way down, even when she eats chicken and chocolate milk, McCoy said.

"She can now have turkey and stuffing," McCoy said. "It's just going to be really special that she can eat a Thanksgiving dinner."