Former NFL star Demaryius Thomas suffered from stage 2 CTE when he died

• CTE is a degenerative brain disease that's common in former football players. It can only be diagnosed posthumously.

What they're saying: "His father and I hope all families learn the risks of playing football," said Thomas' mother, Katina Smith, per the release. "We don’t want other parents to have to lose their children like we did."

• Smith said she had noticed Thomas had isolated himself before his death. "He was just so young, and it was horrible to see him struggle," Smith wrote.

Details: The diagnosis was made at the Boston University CTE Center after Thomas' family donated his brain "to help raise awareness of CTE and encourage the football community to support research," the release said.

• Thomas is one of more than 300 former NFL players who have been diagnosed with CTE by the BU CTE Center research team.    

Of note: The CLF said although there was speculation Thomas's death may be related to an epileptic seizure, stage 2 CTE is not the likeliest cause of post-traumatic epilepsy.

• He is "far more likely" to have developed post-traumatic epilepsy from a car accident or a fall he experienced years before his death, the foundation wrote.

What they're saying: “I hope this is a wake-up call to high-profile current and former NFL players that CTE is rampant among them, and they need to get involved in creating real solutions," said Concussion Legacy Foundation CEO and co-founder Dr. Chris Nowinski, per the press release.