"Stranger Things" star Gaten Matarazzo underwent another surgery for cleidocranial dysplasia, a rare genetic disorder he was born with that affects the growth of his teeth and bones.
Matarazzo called the operation — his fourth — a "big one" but did not go into detail in an Instagram post on Wednesday.
The 17-year-old also urged his followers to learn more about the condition at the CCD Smiles website.
Cleidocranial dysplasia, also known as CCD, affects one in 1 million children and can be passed from a parent or caused by a random mutation, according to CCD Smiles.
The U.S. Department of Health and Human Services said common characters of the condition are dental abnormalities, underdeveloped or absent collarbones and delayed closing of the spaces between the skull bones. There isn't a specific treatment for CCD, but it can be managed with dental work and surgeries to correct any bone deformities.
Matarazzo has been very open about living with the condition and said during a 2018 appearance on "The Doctors" that he was born without collarbones and has more teeth than the average person although they don't grow in properly.
He said that early in his career, he lost roles because of his teeth and a lisp caused by the condition.
"That's one of the biggest reasons why I haven't been getting roles," he said. "I would go three times a week up for auditions and just 'No' constantly."
That changed when he was cast to play Dustin in "Stranger Things," which debuted on Netflix in 2016. Matarazzo said the show's creators Matt Duffer and Ross Duffer, known professionally as the Duffer Brothers, asked if they could incorporate his condition into the show.
"I think what the Duffer brothers, the directors of the show, what they really wanted to do was they really wanted to make sure that each character in the show was unique and they had something that was realistic and personal," Matarazzo said.