I don't recall the name of the diagnosis, but it is a special kind of dwarfism/physical-and-mental evolutionary defect. It affects the brain and intelligence as well, making the person stay with the mind of a 5 to 10 year old all their life. Some maintain an intelligence close to a teenager's, however. There was this teen girl with the diagnosis who appeared to have a mentality close to her own age, but not quite there. She too had a short temper. They also get a lot of health issues very easily, like bad eyesight and damaged joints... and getting pregnant is possible, but lethal for them.
I saw a video with I think the same guy boxing some dudes and someone commented that it was a different type of dwarfism than what affects like Peter Dinklage and other people we think of when we think of midgets. Their's make their limbs short but the rest of their body is normal proportions, and this guys just makes him small. take this with a grain of salt it was a couple months ago I think