HOUSTON, Texas (KTRK) -- It's a genetic trait that may affect many of us without us even knowing it, and in the case of one young football player, it cost him his life.
Now his twin brother is doing everything he can to educate others and help save lives.
"It's a special bond that, you know, never ends," Devard Darling explains. "Life or death, you know, I'll always be close to my twin."
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Darling and his brother Devaughn dreamed of one thing growing up: playing football.
When they both got into Florida State, he says their next step was going to the NFL. But they had to get through a program they knew was brutal.
"Unwritten rules, can't get water, uh, trash cans around for people throwing up all the time," Darling said. "It was just that type of environment."
They both made it through tough training until the day his brother collapsed.
"I excused myself to go down and check on him, and by that time they were, you know, doing CPR on him. It was like a movie, you know, they pushed me out of the room and I started going crazy," Darling said.
"It was the worst, worst moment of my life. You know, I never would have thought in a million years, at 18 years old, I would've lost my twin brother."
His family learned Devaughn died of complications of sickle cell trait, which both boys discovered they had before college. And they found out certain things could be deadly.
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"Not being hydrated, and high elevation and heat, uh, you know, all this stuff that played into, into Devaughn's death."
Now Darling has created the As One Foundation in his brother's honor and its 10th annual fundraiser is coming up this Sunday.
"5K, 10K, run walk for the 10th annual," Darling said. "So it's going to be big. It's going to be fun."
The event takes place at Stude Park in the Heights at 7:30 a.m. Sunday.
You can register for the event at www.AsOneFoundation.org. Use code ABC13Discount at check out for a $6 discount.
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Former Texans player fighting to save athletes after twin's death