Years ago, I remember seeing a Nova, or some such program, about a little boy in England, who had gotten an infection or something wrong with his brain when he was around 2 or 3, and on a ct scan, he only had brain tissue on the areas lining his cranium, with nothing but cerebrospinal fluid filling up the rest of the area where the brain tissue was supposed to be, and he was of normal intelligence. It was quite remarkable.
Well this little fellow is far beyond that.