Face blindness ...

... You Don't Look Like Anyone I Know | Books and Culture.

Prosopagnosia ... is not a mental illness, not like the paranoid schizophrenia that Sellers finally claims as an explanation for her mother's behavior. The condition, both a genetic inheritance and an end result of Sellers' bewildering childhood, comes as an inability of the brain to put together the parts of the face; Sellers knows who her friends are, but when she sees them, noses and mouths don't register as belonging to that particular person. Even her mother's face is something that Sellers cannot visualize.