- Causes mental retardation or severe developmental delays from birth.
- Can be healed by rapid cell regeneration. You know, the superpower that Claire from Heroes or Wolverine has.
- Wouldn't require the individual in question to use modern medical equipment to live, like a feeding tube.
- Has some sort of genetic or environmental component because I want two brothers of different ages to have it.
It's the healing factor that is tripping me up. Genetic disorders are obviously out. I understand that encephalopathy can be caused by a variety of things, but I'm not clear on the details. I'd like for the brothers to have the same problem.
Googled: causes of mental retardation, encephalopathy, brain damage.