There's a reason nerdy preteen Dustin Henderson doesn't have any front teeth in seasons one and three of 'Stranger Things.'
According to CNN, it's because actor who plays him, Gaten Matarazzo III, has a rare bone condition.
He was born with cleidocranial dysplasia, or CCD, a rare disorder which primarily affects growth of teeth and collarbones.
Like many celebrities, Matarazzo is using his new fame to bring attention to the condition.