Reminds me of the book Far From The Tree. The deaf have formed proud communities but have also spawned zealous subcultures that are effectively cults. Some seriously suggest that deaf children should be taken away from unafflicted parents.
Probably not what you're thinking about, but book three or four in the Ender's Game series (Orson Scott Card) has a community of very OCD people (women?), which are revered as being holy. During the book it is discovered that the cause is genetic, not from the divine. A cure is developed, which almost all of the community take, but the head priestess refuses to get the cure, insisting on believing that she is divinely touched and remaining enslaved to OCD compulsions.
