Are other diseases or disorders like CIPA that could cause people to perform superhuman feats?

CIPA doesn't cause people to perform anything superhuman, it just gives them the inability to feel pain which can be an extraordinary hindrance in everyday life. Imagine hurting yourself and not knowing it, say breaking a bone or obtaining a severe internal injury. It can be horribly debilitating and possibly deadly/ There have been cases of people with down's syndrome and other forms of mental retardation to have certain extremely heightened senses for certain subjects. These people are often called "savants." For example the movie Rain Man was loosely based off of a true story in which a mentally challenged man could not forget anything he was told. This didn't make him technically smart as he couldn't understand any information he remembered, but he could truly remember all of it and exactly as it was presented to him. Other savants have been known to be able to listen to highly complex musical works and flawlessly reproduce them on an instrument without practice. I remember also ...  more