The first death in Northern Ireland due to second impact syndrome has been recorded at a 14-year-old boy's inquest.
The coroner at the hearing in Belfast said it was also "probably" the first such case in the UK.
Ben Robinson, from Carrickfergus, County Antrim, died after suffering concussion during a school rugby match.
The syndrome happens when a blow causes swelling to the brain before it has recovered fully from an earlier injury.
The schoolboy was in several heavy tackles before collapsing near the end of the game in January 2011.
He had been momentarily knocked out at the start of the second half of play.
His parents had argued he should have been taken off the pitch at that point in the game.
The coroner said this was the first recorded death due to second impact syndrome in Northern Ireland and probably in the rest of the UK.
She is sending a copy of her findings to the head of Irish Rugby and to the education minister.
The coroner said this was a case of great public interest and she believed everybody should learn from it.
The Carrickfergus Grammar schoolboy was seen holding his head before collapsing during the game against Dalriada and later died in hospital from brain injuries.
In a statement, the Irish Rugby Football Union (IRFU) and Ulster Rugby expressed their "deepest condolences" to the Robinson family and said player safety was a priority.
"Injuries of this nature are highly unusual in rugby," the statement said.
"The IRFU and Ulster Rugby observe all international best practices, as set out by the International Rugby Board. We have in place, and continue to develop, education and training campaigns to ensure player welfare is prioritised at all times."