One of the youngest victims of severe head trauma linked to American football was a 25-year-old high school and college football star who died two years ago, researchers have discovered. Michael Keck suffered severe memory loss and temper tantrums before he died of a congenital heart defect.

A study of his brain by Boston scientists found clumps of abnormal tau protein scattered throughout his brain. It was one of the key signs of chronic traumatic encephalopathy (CTE), which is found in boxers and football players because of repeated trauma to the brain.

"It was the worst CTE I've seen in an individual this young" said Dr Ann McKee, a professor of neurology and pathology at the Boston University School of Medicine. "He started playing when he was quite young," McKee told NBC. "So he had 16 years of football behind him. That's a lengthy exposure. Brain injury is cumulative."

Keck, who started playing football at the age of 6 growing up in Kansas City, suffered 10 concussions by his third year in college when he attended Missouri State University. He became extremely sensitive to light, suffered severe headaches and was unable to concentrate on tasks. By the age of 25 he was no longer capable of working.

Because he long suspected his problems were due to football, he asked his wife to donate his brain to science for study after his death. McKee, whose study was published in JAMA Neurology, believes child athletes should avoid head contact.

"If you're going to play [tackle] football, put it off until the body matures completely, until the body size has caught up with head size, until the muscles are coordinated," McKee said. She added that she was "blown away" by Keck's case. "This case still stands out to me personally. It's a reason we do this work," she told the Kansas City Star. A young man, in the prime of his life, newly married, had everything to look forward to. Yet, this disease is destroying his brain."

National Football League (NFL) players have been battling for years with officials over better head protection and safety measures, and compensation for head trauma. The Keck case points out significant risks for amateur players as well. "Those are the people we probably need to know a lot more about," said Columbia University neurologist James Noble.