What disease is the opposite of progeria?

Peter Pan Syndrome: We all would like to find the fountain of youth. If researchers can find out the genetic make up of Progeria, maybe we will get a clue. Peter pan refused to grow up and there are many adults who fit into that category. LIfe is what we make it. Enjoy every moment. Carpa diem!

None yet: There are at least three people who showed slower aging than normal. One, Brooke, was evaluated and her DNA examined. The genes responsible for Progeria were unaffected in her and the cause of her poor growth was never found, Another, now over 40 years old and depicted here, is physically like a ten year old but has no language and so far has had no etiology found for his growth

None: There isn't a disease known that is the actual opposite of Progeria.