In 2012, star soccer player Patrick Grange died of amyotrophic lateral sclerosis, or ALS, at the age of 29. His brain was donated to a hospital for analysis, and to the examining doctors’ surprise, what they found were traces in his frontal lobe of chronic traumatic encephalopathy, better known as CTE.

Grange is the first soccer player to receive this posthumous diagnosis. It’s also surprising given the sport he played. Ever since researchers began analyzing athletes’ brains for CTE in the 1920s, it’s traditionally been a hallmark disease of boxing and football, and occasionally hockey, as a product of the myriad sub-concussive blows to the head. Now soccer is lumped into the mix, and experts are pointing to the sport’s iconic header as the enemy.

In your average soccer game, a player may head the ball up to 12 times — to say nothing of the drills during practice. Traveling at upward of 50 mph, the ball strikes a player’s forehead with the same force as a punch from an amateur boxer. Outside of sports and physical abuse, this behavior is simply alien, Chris Nowinksi, director of the Sports Legacy Institute, told ABC News. “Getting hit in the head hundreds of thousands of time is not a normal part of life,” he said.

But for athletes who dedicate their lives, and later donate them, to sports, these repeated blows are business as usual. Michele Grange, Patrick’s mother, said her son began heading soccer balls when he was only 3. He would toss the ball to himself and bump it into the net, over and over and over. It was only after his brain was analyzed following his death — the proteins of CTE can only be found after death — that the Granges noticed how prevalent the CTE was in the early years, The New York Times reported. Grange would struggle to balance a checkbook and fail to notice the dangers of failing grades. He once took a soccer trip cross-country, but forgot to let his employer know he was taking time off. So he lost his job.

If they could do it over again, Grange’s mother told the Times, they would have prevented him from practicing headers too early. She and her husband caution other families whose children are serious about soccer to wait until the athlete’s teen years before taking up the risky strategy. “When I see the little kids playing soccer, even my grandson, for one thing it reminds me of better days,” she said. “But on the other, it makes you think of the consequences.”

Of which there are many, experts argue. By the time athletes’ brains stop developing, generally around age 25, many of their heads have already been exposed to some 20 years of constant sub-concussive force. Inside the skull, the brain sits in a bath of cerebrospinal fluid. This cushions the organ when it’s jostled around for one reason or another. But in sports the CSF can only do so much; repeated force causes the brain to crash into the inside of the skull, damaging the areas pounded most often.

In Grange’s case, Dr. Ann McKee, a neuropathologist at the VA Boston Healthcare System and the doctor who helped analyze Grange’s CTE, found the disease in the brain’s frontal lobe. On a four-point scale of severity, McKee pegged Grange’s injuries as a two.

“He had very extensive frontal lobe damage,” McKee told the Times. “We have seen other athletes in their 20s with this level of pathology, but they’ve usually been football players.”

Dr. Michael Lipton, an expert in magnetic resonance research at Albert Einstein College of Medicine at Yeshiva University, said the trend can only continue until research takes a hardline stance. Lipton and his colleagues recently conducted a study that found the more times a player headed a soccer ball over the course of a year, the more likely he or she was to display reduced cognitive function and exhibit signs of brain damage — a less-than-hopeful outcome for the world’s most popular sport.

“The thing that is unique about soccer,” Lipton told ABC News, “is people are doing this again and again and again.” And if Grange’s case is anything to go by, CTE will also appear, regretfully, again and again and again.