Jichi Medical University in Tochigi Prefecture said Thursday it successfully transplanted part of a father's liver to his 17-day-old girl, who weighed only 2.6 kg, last October.

The baby is the youngest and smallest recipient in terms of weight among some 4,600 liver transplants that have taken place nationwide so far, the university said. On a global scale, the baby was the world's third-youngest liver transplant recipient and the second-smallest recipient in terms of weight.

According to the university, the baby weighed 2.7 kg when she was born in Miyagi Prefecture. But she started to show abnormal symptoms such as vomiting blood and was diagnosed with "fulminant hepatitis of unknown cause."

With no other way to save her besides a transplant, the baby was taken to Jichi Medical University Hospital by helicopter.

Her liver, which had contracted to about 25 grams, or less than one-third of the normal weight, was taken out and a 95-gram section of her father's liver was transplanted.

The surgery took about 15 hours and ended successfully, the university said. Her weight has recovered to about 3.7 kg after overcoming accompanying medical problems and she was discharged from the hospital on Dec. 27.