Prosopagnosia: an impairment in the recognition of faces; the inability to recognize faces caused by damage to the fusiform gyrus (the fusiform gyrus is part of the temporal and occipital lobes of the brain and is used to 1) processing of color information, 2) word recognition, and 3) face and body recognition).
Cotard's Syndrome ("Walking Corpse Syndrome"): a person believes that they are dead (literally or figuratively); this disorder is not listed in the DSM-IV; is said do be caused by a misfire in the fusiform face area (facial recognition).
In Season 1, Episode 5 of Hannibal, Georgia Madchen has both disorders and, because of her poor mental state, kills one of her friends and goes missing. Although Georgia has killed her friend, she is portrayed in a way that makes the audience feel sympathy for her. The typical media stereotype of portraying a person with mental illness as too dangerous to function independently in society is avoided. Georgia seeks help for her illness, well-knowing that she is a killer, but is sadly murdered before treatment can begin.
As for the illnesses themselves, both prosopagnosia and Cotard's Syndrome are caused by a misfiring in the fusiform gyrus (an are in the occipital and temporal lobe). This provides a connection as to why the chances of Georgia having multiple diseases of the sort increase exponentially when part of the fusiform gyrus is not correctly working.
A better pyschological understanding of this aspect of Hannibal provides the audience with a more realistic view on Georgia Madchen. One can now understand and sympathize with Georgia, because, although she did kill someone, she was looking for treatment to make amends for what she had done. The more accurate portrayal of someone with these illnesses also reflects upon the knowledge of the writer of Hannibal; clearly they did their research.