There are at least two types of prosopagnosia.
One type is congenital or developmental prosopagnosia where there appears to be no brain damage. At this point it is a lifelong facial-recognition deficit that typically manifests early in childhood. It has a prevalence rate of 2.5 percent. Studies have shown this type to be completely compatible with compatible with autosomal dominant inheritance.
There is also an acquired form that exhibits after the brain has sustained some type of damage or injury, the type that Dr. Sacks addressed in his book. Interestingly, instances have been reported where acquired prosopagnosia spontaneously resolved on its own. More tomorrow