From the 1980s theme to Steve Harrington’s curled-up-to-the-gods hair, fans of Eleven, Mike, Lucas, and Dustin’s friendship have come to cherish every strange and weird thing that happens in Hawkins, Indiana — especially those visually peculiar trips to the Upside Down. There are so many things to love about Netflix’s original series Stranger Things — and Gaten Matarazzo‘s teeth is one of them! Dustin Henderson, the standout nerd of the friend group, is played by Gaten. IRL, the 15-year-old has a condition called cleidocranial dysplasia, a physical trait and personality quirk the Stranger Things team literally wrote into the script for his character.

“I don’t think we really understood who that character was and then we met Gaten and basically tailored the show to him,” show creator Matt Duffer told The Daily Beast.

Gaten’s real-life diagnosis paved the way for his character’s on-screen nickname, Toothless. It also gave Gaten the opportunity in one scene to shut down a bunch of rude bullies who were strong-arming his character about his teeth. But the coolest part about it? Gaten reveals that by writing CCD into the show, many people who also suffer from the condition have reached out to him, thanking him for giving them representation in one of the most-watched TV series of the 2017.

“It’s a very rare condition and not many people have it around the world. When they wrote it into the show, I [started] getting a lot of messages and emails online from people who have the condition, saying that it really helps them come out of their shells a little bit,” Gaten has said. “Because a lot of people have it much worse than I do and it affects them much worse than it does me. I’ve always liked to embrace the condition but other people don’t feel the same way.”

Ever since being cast on ST in 2016, Gaten has been outspoken — both in interviews and through his massive social media presence — about how CCD affects his life (and his character). He’s even been completely transparent about sometimes wearing fake teeth.

He captioned the below Instagram photo, “Just letting you guys know. These are fake teeth. #toothless.”

“[Fans with the condition] say that because this was in the show and this is the first time they’ve heard of it outside the doctor’s office, it made them feel really good and it inspired them,” Gaten continued.

“Those messages really inspired me and made me feel good and appreciate the Duffers even more. I look up to them like they’re my older brothers. I mean, they’re just great guys. They inspired a lot of people to come out of their shells and embrace what they have,” he added.

According to CCDSmiles, CCD is a rare genetic disease that affects a person’s skeletal development, defined by open fontanelles (or what’s called a soft spot), small or missing collarbones, and myriad dental issues.

“There’s a one in a million chance that you have of getting it – most likely you get it from a parent, but it just happened for me,” Gaten told People. “I have a very mild case so it doesn’t affect me as much, but it can be a very difficult condition to have.”

CCD can be accompanied by a lot of other serious health issues such as Osteoporosis, flat feet, and partially or fully missing clavicle bones. For some, dental issues are the least of the diagnosed person’s concern but Gaten noted he’s very lucky to have a mild form of the condition. People with dental issues from CCD often lose their baby teeth late, which causes their adult teeth to come in even later. Hence Dustin’s nickname — Toothless!

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