Face Blindness - hereditary prosopagnosia

One of the most striking consequences of damage to the medial occipitotemporal region of the brain can be the loss of the ability to recognize familiar faces. Patients know only that a face is a face, and can name its parts. There is a website devoted to this disorder. The accquired condition is rare, and inherited or congenital forms of prosopagnosia have been assumed to be even more rare. Kennerknecht et al., however, have now shown that in one group of 689 students, 17 (~2.5%) had congenital prosopagnosia. It turns out that this condition can easily go undiagnosed, because subjects develop alternate strategies for identifying people — they remember their clothes, mannerisms, gait, hairstyle or voice, and by using such techniques, many can compensate quite well. Bakalar, in a review of this work in the July 18 New York Times, notes that people with face blindness can typically understand facially expressed emotions — they know whether a face is happy or sad, angry or puzzled. They can detect subtle facial cues, determine gender and even agree with everyone else about which faces are attractive and which are not. In other words, they see the face clearly, they just do not know whose face they are looking at, and cannot remember it once they stop looking. A specific gene for the disorder has not been found, but evidence is mounting that the trait is inherited. The pedigrees that have been established so far are compatible with autosomal dominant inheritance.”