DURHAM, N.C. — Annabelle Green is a playful 2-year-old with a serious condition. Duke Medical Center is the only hospital in the world that will treat it. In her case, there is both medical and musical treatment.

Annabelle has a rare disorder called Sanfillipo Syndrome.

"It causes brain damage. It's a very horrific disease," said Jennifer Loves, Annabelle's mother.

Last month, Annabelle underwent a stem cell transplant. Without it, the disease is fatal. The disease has taken half of Annabelle's hearing. However, Loves said she was watching "Elmo Meets The Orchestra," when she became inspired to play music for her daughter -- something she had not done in years.

"It was not even in my consciousness that I was going to pick it up and start playing again," Loves said.

Loves said someone donated a viola for her to play for her daughter.

"It's stimulating all the way around, and I really believe that it helps," she said.

Annabelle hopes to leave the hospital soon. She still faces months, if not years, of treatment, but she and her mom cling to the sound of hope.

"I'm very optimistic," Loves said. "I'm extremely humbled by how strong my little girl is."

Duke Medical Center has performed 11 transplants on patients with the same condition as Annabelle, of whom five have died. Annabelle will be the 12th patient, and she may need another transplant depending on her test results. She will find out what they are next week.