Pretty sure there were missing teeth.

Edit: not Otto. Might have been another prisoner. Or I’m confusing it with World War Z and how North Korea solved the zombie crisis by pulling everyone’s teeth.

Edit edit: ok, he’s the one I read about but these details aren’t in wikipedia and may be suspect.

They said Otto was deaf, blind, jerking uncontrollably and making “inhuman” sounds when they met him on a plane.

His teeth also looked like they had been rearranged with pliers, his father said.

https://www.mirror.co.uk/news/world-news/he-totally-deformed-otto-warmbiers-11242029