Updated

An autopsy has been performed on a 1-year-old Japanese boy who went into cardiac arrest aboard a flight about an hour before it landed at Honolulu International Airport.

The city medical examiner's office says there was no preliminary cause of death determined for Hyeondo Seo of Tokyo.

State Department of Transportation spokeswoman Tammy Mori says the child was traveling with his parents aboard China Airlines Flight 18 from Narita International Airport when he went into cardiac arrest Tuesday morning.

Mori says a doctor aboard the plane performed cardiopulmonary resuscitation but the child was unresponsive.

She says a medical team met the flight and took the boy to the Kaiser Permanente Moanalua Medical Center, where he was pronounced dead.